I posted a review of the Jackery 1000Wh solar generator earlier this month with my overall impression being that it is a very well designed and built power supply which can power even the hungriest astronomy setup for 8-10hrs without needing a recharge. While the Jackery can be recharged fastest with an AC outlet using the supplied charging cable, it can also be recharged quickly during the day using Jackery's Solar Saga 100w solar panels. Here I review the results of over a month's testing of a pair of 100w solar panels along with the generator both at my home observatory and during a 3 night trip to a dark site.
Jackery makes two versions of their solar panels, a 60w and a 100w model. While I tested a pair of the 100w models, they share design features with the 60w model as described here with the differences being size, weight and power output. Both panels use Monocrystalline solar cells with up to 23% efficiency and a voltage output of 18V and a current of 5.55A. The panels have over voltage, short circuit and surge protection built in. They have an operating temperature range of 14 deg F to 149 deg F. They come with a 24 month warranty but an included registration card will extend that to 36 months. The 100w panel is 48in x 21in x 0.2in when fully extended to capture the sun's rays. For transport and storage it conveniently folds in half. A pair of magnets cleverly embedded in plastic at two corners of the panel help to keep the panel folded when not in use or during transport. It also has a built in rubber carrying handle and weighs only 9.1lbs. All of these smart design features make it very easy to transport and set up in the field.
Each half of the full panel has a kickstand which stays put with velcro for travel and can be extended to support the panel when charging. The panels have a protective laminate layer for dust and weather resistance. A zippered pouch on the backside holds the 3m charging cable which is hard wired to the panel. The 8mm connector on the other end plugs into the charging port on the Jackery when charging the generator. Each panel also has a 5V 2.4A USB-A and a 5V 3A USB-C charging port on the backside so that a cell phone or tablet can be charged directly from the panel with the proper charging cable. Overall, I am impressed with the quality of the build and cleverness of the design making it easy to use. I give Jackery an A+ for design smarts and convenience.
I ran a series of tests with the 1000Wh solar generator using my typical astrophotography imaging setup over 4 weeks at my home observatory and in a three night field test at a dark site location. In between tests I had multiple occasions to recharge the generator with the pair of 100w solar panels under varying sky conditions including best (full sun) and worst (overcast) case skies along with the in between cases of partial sun and clouds. To use two solar panels a Y adapter cable which is supplied with the 1000Wh generator is used to combine the outputs of both solar panels which are then fed into the generator's input port. It is not absolutely necessary to use both solar panels but the recharging time will be significantly reduced with two panels instead of one. I should point out that all of these took place in late September and early October as we moved into fall and the sun is lower in the sky and the days are roughly 11hrs long.
The first thing I checked was the output of each solar panel. Keep in mind the output power of a solar panel varies with sun intensity and angle of the panel relative to the suns rays. Maximum output is seldom achieved, and when it is it is not sustained over long periods unless you re-align the panel due to changing solar intensity and angle. The meter on the Jackery 1000Wh generator showed that panel #1 was charging at a rate of 87/88w on a sunny day which is well within what other reviews have shown. Next I tested the second panel but its output was only 42/43w. Clearly the second panel was not performing up to spec. I contacted Jackery and they made arrangements for the second panel to be returned to them and a new one sent in its place, but since I was headed to a dark site for new moon in a week I asked them to wait until after my excursion to replace the second panel and forged ahead with the panels I had on hand. On a very sunny day the input to the generator with the pair of panels connected in parallel with the Y adapter cable varied from 118w to 125w over the course of the day as it charged from 20% to 100% in just 7 hrs. This rate of charge says that it should take ~ 8.75hrs to fully recharge the battery from 0% to 100%, which is in line with the advertised time of 8hrs.
Not all days will be sunny so I checked how well the panels worked during several days with very little direct sunlight. The second solar recharge took place during the massive CA wildfires including three of the largest in the state's history very close to my home. With smoke filled hazy skies the entire day, the panels were able to recharge from a SOC of 23% to 100% in approximately 9.5hrs. The input to the solar generator typically read between 80w and 90w for much of the day. Apparently, enough UV light made it through the smoke particles in the sky. I was quite surprised.
For the third solar recharge I picked a day with periods of partial sun, high thin clouds, but mostly a steady overcast condition. The output power of the panels fluctuated from 0w to 122w but hovered mostly around 22-48w throughout the day. In this case the two 100w panels could only provide enough power to recharge the generator from 18% SOC to 67% SOC in 9 hours. The Jackery panels are not unique in this regards as no solar panel can provide much output if the sun doesn't shine. But I was impressed that even under these gloomy skies I was able to recharge the generator by almost 50%. Odds are that if the day is that overcast we would not expect a clear night for astronomy so this would not be a problem.
The charging rate was very linear with the SOC increasing just over 9% per hour of solar exposure up until the final 1% percent. This is nice in that, if the sky conditions are expected to remain fixed throughout the day, one can make a fairly accurate estimate of how long it will take to recharge under different sky conditions.
During my 3 night field trip to do astrophotography during the new moon I had the opportunity to recharge the panels after the first two nights. The first night I spent 8 hours imaging resulting in the generator dropping to 28% SOC. With full sun the next day I was able to fully recharge the generator as well as top off my laptop battery with Jackery's pass through charging option in a bit over 6 hours. Pass through charging allows the generator to be recharged at the same time it is supplying power to a load. The second night I imaged for only 6 hours and was easily able to recharge the generator in less than 6 hours in full sun. With this setup I could have easily imaged 8 hours a night indefinitely, fully recharging the generator, laptop and my cell phone during the day with the solar panels so long as I had ~7 hours of sunshine.
Once I returned from my field trip I returned the under performing panel to Jackery with a prepaid voucher and quickly received a replacement. The first thing I did was to test it against the first panel under fully sunny skies. This time both panels consistently output 96/97w of power in tests on two different sunny days. This is exceptionally high compared to what I have read for any 100w solar panels on the market. Obviously the sun's intensity and angle or both are extremely important to obtaining maximum power output. I could easily improve the output by ~10w carefully adjusting the azimuth and angle of the panels.
Next I checked the output with the pair of panels connected in parallel with the Y adapter. The configuration produced 129w of input power to the generator which remained steady over time. Why not 192W you might ask yourself. If you read my review of the solar generator you will see that with the supplied AC adapter the input power was 164w. Then why the difference with the two 100w panels? Well, I read in one review that the Jackery limits the total input current and since the AC adapter supplies current at 24V that would mean that the current limit is 164w/24V = ~7A. Considering that the solar panels supply current at 18V, and assuming the same current limit of 7A that would set the maximum input power at 18V x 7A = 126W which is very close to what I measured. The net result is that one does not get the full advantage of the two 100w solar panels due to this current limitation which is disappointing.
The input power limit of ~126w led me to the next test measuring the total recharge time with a single 100w panel. I monitored the panel output hourly and used that opportunity to adjust the position of the panel to maximize its output, thereby keeping above 90w for most of the time. Since the days are shorter now and the sun is lower in the sky I had to run the test over two days to fully recharge the generator from 1% to 99% SOC. It took a total of 10.5hrs to recharge completely, which is a rate of 9.3% per hour and the rate was very steady all the way up until 99%. 9.3% of 1000w is 93w which is consistent with my observation of the fact that the output remained above 90w for most of the charging period. Also, 93w x 10.5hr = 977Wh which is also consistent with the fact that the SOC went from 1% to 99%, or 98% of 1000Wh = 980Wh. So, I suspect that during the typical star party season with the sun rising earlier and setting later than it does in Nov, one could fully recharge the 1000Wh generator with a single panel in one day.
Overall, I was suitably impressed with the build quality, design smarts and obvious capabilities of the Jackery Solar Saga 100. My truly on complaint is the price. At a price of $299.99 the Jackery 100w solar panels are more expensive than other folding panels. However, none of the other folding panels I have reviewed on line appear to have as durable, compact and ergonomic design as the Jackery. Nonetheless, it is best to keep an eye out for one of Jackery's sales to get the best possible price.
High efficiency solar cells
Lightweight with handles
Sturdy, durable design
Embedded USB charging ports
No protective case
Hard wired charging cable
If you want to find out more about Jackery's products here is a link to their official website jackery.com As a Jackery Affiliate I can earn from qualifying purchases when you link from this site and it will not cost you any more than if you linked directly on your own.
I have been powering my astronomy rig in the field using either two 100Ah lead acid deep cycle batteries or my Yamaha EF2000is generator for a dozen years. While relatively cheap, batteries are heavy (50-60lbs), can only be discharged to 50% of capacity, are not voltage regulated, need to be maintained monthly, and do not have built in meters, USB charging, AC output, etc. At $1000 a generator is expensive, heavy (~50lbs), does not have either DC or USB outputs and is not permitted at most star parties. So I decided it was time to look at Li based power with solar recharging. Why Li? Because the power to weight ratio is much, much better than lead acid batteries, Li batteries have a higher depth of discharge (DoD) than lead acid batteries without damage and they maintain their voltage through most of the discharge cycle. The obvious downside to Li based power is the higher initial cost.
At first I considered 100Ahr LiFePO4 batteries like the well regarded Battleborn batteries marketed primarily to the RV and boating industries since I am planning to use these to add solar to my new RV in the coming year. But after much research I decided that a "solar generator" rather than a standalone Li battery is a much better match for astronomy applications. What is a solar generator? It is a Li battery with a battery management system (BMS), DC, AC and USB outputs, power input/output/SOC meter, an LCD display, power charging ports and a solar charge controller all built into a single lightweight, rugged and portable unit. There are many different suppliers of solar generators available today which are primarily marketed to the outdoor adventurer. Many solar generators use Lithium Nickel Manganese Cobalt Oxide (NMC) chemistry instead of LiFePO4
because of its nearly 2 to 1 advantage in energy density to weight ratio. I zeroed in on the solar generators from Jackery after reading many positive reviews about their design, features and performance. Their line of solar generators includes 160Whr (13.9Ah @ 12V), 240Whr (20Ah @ 12V), 300Whr(25Ah @ 12V), 500Whr (41.7Ah @ 12V) and 1000Whr(83.5Ah @ 12V) models with prices ranging from $139.99 to $999.99 with frequent sale pricing. These provide plenty of options for different astronomy needs. I contacted Jackery and suggested that amateur astronomers might be a market for them and they were kind enough one of their 1000Whr generators with a pair of their 100w solar panels for me to put to the test with my astronomy rig. Below are the results of more than a month of extensive testing in my backyard observatory and on a 3 night star gazing adventure in the field.
The Jackery comes well packaged with the generator shipped triple boxed. The PS1000 generator includes an AC charger in a soft carrying case, a car charger cable, an adapter to connect two solar panels in parallel for faster charging and a user manual. It enjoys free shipping, a 30 day free return and a 2 year warranty. Inside the box I found a registration card which enables a warranty extension to 3 years. The generator is solidly built using rigid ABS plastic casing and sports a smart functional design. With dimensions of 13.1 x 9.2 x 11.1 in. (L x W x D) it is only slightly larger than my lead acid batteries and fits nicely between the tripod legs of my mount. It's molded handle and weight of only 22lbs makes it a breeze to transport. Everything one needs to access is conveniently located on the front of the generator including:
1) a 10A DC cigarette adapter socket with dust cap;
2) a 5V 2.4A USB-A output ;
3) two 3A USB-C outputs;
4) a USB-A Quick Charge 3.0 output;
5) three 110V AC outputs from the internal 1000w pure sine wave inverter;
6) 8mm and Anderson Power Pole inputs to recharge the generator;
7) an LCD display which shows power output, input and battery % SOC and is low enough intensity as to not disturb fellow astronomers.
8) On/Off buttons for the power outputs and the display.
A small LED light is mounted on the side. The Jackery can be recharged with the included AC charger, with optional solar panels or by car.
I conducted a series of tests of the Jackery using my Software Bisque MyT mount, Celestron C11 OTA, Celestron focuser, ASI1600MC camera, Orion SSAG guide camera (not shown in the accompanying photo), Astrozap dew heat strap, TEMP-est cooling fans, and a Pegasus Power Box Advanced (PPBA). I used a cigarette adapter to 5.5mm x 2.1mm cable to supply power from the Jackery to the PPBA which in turn distributed power to the MyT, dew heater and focuser. The cameras and fans drew their power from the MyT. Since the MyT requires 48V I used a DC-DC up converter on the output of the PPBA to transform 12V to 48V rather than using the less efficient AC adapter. I use The Sky X (TSX) to control everything except the PPBA which is controlled by its own application. I did run one test using the Jackery's AC outlet to power the MyT without any problems but that method unnecessarily wastes power in the conversion process.
Since the first month of testing occurred during the massive wildfires here in CA I could not actually image. Instead, I ran everything exactly as I would during a regular imaging session with the ASI capturing dark frames to the laptop, the fans running, the guider taking dark frames and the heater powered at 50%. Since a laptop is typically the most power hungry device used and not everyone uses the same laptop, if they use one at all, I decided to run 3 different test setups:
1. Everything but the 15.4" laptop powered by the Jackery through the PPBA.
2. As in 1 but with the laptop powered through the Jackery's AC inverter.
3 As in 1 including a BeeLink mini-pc powered by the Jackery through the PPBA. The Beelink ran TSX and I used my laptop on its internal battery linked to the Beelink via Team Viewer as a monitor only to minimize power consumption.
For these tests I tried not to discharge the generator batteries below 20% SOC to be very conservative in terms of long term battery lifetime. The manufacturer specs the batteries to > 500 full discharges to 0% SOC so you could increase all of my total times below by 25% if you are comfortable using the full capacity of the Jackery. Here are the test results:
Test #1: I was able to achieve a total run time of 27hrs over 3 successive sessions before reaching a SOC of 20%. That is enough power for 3 nights of 9 hour imaging sessions without the need for a recharge in between, although a recharge is always possible. I noted that the ouput voltage of the Jackery remained steady at 12.9-13.1V all the way down to 20% SOC.
Test # 2: To extend the session as long as possible, I disconnected the laptop from the Jackery when it reached a SOC of 25% and let the laptop run on its own internal battery until it reached ~5% and the Jackery reached 20%. This powered everything for 9hrs, sufficient for a long overnight imaging session powering everything with the Jackery. Considering that the Jackery was able to be fully recharged with 2 solar panels in 7.5hr , one could run indefinitely this way so long as a reasonable degree of sunshine is available during the day. Alternatively, the Jackery could be recharged in 6-7hrs with an AC outlet.
Test#3: For this test I only used my laptop on its internal battery to check in on the BeeLink via Team Viewer occasionally. As I show below, the BeeLink which has no monitor consumes much less power than a 15.4" laptop so I was able to run for 8hrs and only draw the Jackery's SOC down to 59%. At that rate of power consumption I should be able to run for 15.6hrs without dropping the Jackery below a 20% SOC. That is nearly enough power for 2 nights of 8hr imaging without the need to recharge in between. Or I could use the extra power of the Jackery to keep my laptop powered using it as a monitor to check on imaging progress from time to time.
Actual Field Tests
While the tests at my home observatory are telling, there is nothing like an actual test in the field. So, just after the October new moon and with clear skies at last I headed to a dark sky site along the central CA coast. I did not use the SSAG since I wasn't guiding and I also did not need the heater. However, for all three nights I powered my laptop with the Jackery as in Test #2 above for a completely self contained test of the Jackery. The first night I powered everything up at 6:17PM, just before dark and rough aligned on the crescent moon. As it turns out, my first night would be one of frustration as I learned after running a 120 point TPoint model that my PA was way off. It took a second TPoint run for me to realize that my daytime mechanical alignment was so far off that I had to rotate the entire mount and tripod and adjust the gross altitude pin on the mount to have any hope of an accurate PA. After 2 more TPoint runs I finally got a good PA and was able to begin imaging the M74 galaxy in Pisces at f/10. I typically dislike first nights in the field given my history of such self-inflicted wounds. My frustration actually provided a good power test since the mount spent a great deal of the first 4 hrs slewing back and forth across the sky more than 500 times. I powered down at 2:15 for a total run time of 8hrs with the laptop still fully charged and the Jackery at a SOC of 28%. In other words, I could have run for another 2 hours if I had been able to stay awake. During the next day I fully recharged the Jackery with the solar panels in about 6hrs so it was ready for the following night.
I ran for 6hrs on the 2nd night completing my image collection of M74 and finishing with 50% SOC, easily recharging once again with the solar panels during the next day. The final night I ran for another 6 hrs finishing with 47% SOC as I imaged the edge on spiral galaxy NGC891 in Andromeda. Overall, the Jackery performed as I had expected allowing me to image for as long as 8-10hrs had I been able to stay awake, fully recharging each day with two 100w solar panels to be ready for the next evening. I was also able to use the Jackery during the day using its pass through charging feature to keep my cell phone recharged. Pass through charging allows the Jackery to simultaneously charge a device like the cell phone or laptop, while it is itself being recharged by solar or AC power. It will take correspondingly longer to recharge the generator depending upon the power used to recharge the connected device.
Power Use Case Analysis
Since everyone uses different equipment for their setups, I used the PPBA to measure the power requirements for each individual device and built the power consumption table shown below. Since my camera does not have cooling, I borrowed an ASI294MC Pro with cooing from a friend and measured the power requirements for three different degrees of cooling. Not surprisingly, the biggest power draw by far is my laptop and that is with the display turned down, Bluetooth and WiFi turned off. The camera cooler and dew heater on full are the next biggest power hogs. I find that I can usually run my heater at 50% with a dew shield and not have any dew problems, but others may find they need to run full power. Also, smaller OTAs will require smaller heater straps and correspondingly less power. The MyT mount power increases during slews but as I found when running TPoint in my field tests, 15w is a good average power consumption to estimate the total power needs for this mount if running by DC. In the past I measured the current requirements for a number of different mounts (CGE, CG5, Nexstar 6", ETX80 and IOptron Cube) and found that they use significantly less power than the MyT ranging from 2w to 6w during tracking. The ASI1600 is typical of cameras, including guiders, which operate on 0.5w or less without cooling. I do not have a powered filter wheel or camera rotator but I suspect that the power draw from those is negligible since they are used sparingly through the course of the night.
Taking these numbers into account, the following table summarizes the power required for each of my test cases and the corresponding maximum capable run time for discharges to 20% and 0% SOC of the Jackery. I added an additional case called "Hypothetical" which is identical to my Field test with the laptop powered by the Jackery up until the last 2 hours, but I added the additional power requirements of the dew heater at 50% power (10w) and a camera cooler at 100% power (20.5w) to get a total power requirement of 112w. One can see that for a setup that draws between 40 and 60w, fairly typical of an imaging rig using a mini-pc or a separately powered laptop, the Jackery 1000 can supply multiple nights of power without a need to recharge in between. Even in the most power hungry 'Hypothetical" case the Jackery 1000 can supply power for a long night of imaging.
As noted above, the Jackery has a regulated power output. In my tests, the output voltage remained between 12.9 and 13.1V all the way down to 15% SOC showing excellent power stability. Another thing to note is that the drop in SOC was very linear with time, falling by the same % each hour all the way down to 15%.
Like all other solar generators that I have investigated, Jackery specs the battery life to >500 full cycles after which the full capacity of the batteries will drop to 80%, or 800Wh for this particular model. At that point it will still supply 80% of its original capacity so one would still be able to get continued use out of it but the total run time would be shorter than during the first ~500 or more cycles.
The Jackery can be used to power devices over the temperature range of 14deg F to 104deg F which will cover the typical star party season but might be a problem for hardy soles who like to observe away from home during frigid nights. Recharging of the Jackery requires a temperature above freezing, 32deg F, but I read of a clever trick where the generator is placed inside a cooler so that it stays warm enough under its own heat while recharging at temperatures below 32deg F. These are limitations typical of Li-chemistry batteries and it should be noted that the BMS will prevent the battery from being used outside these conditions so it cannot be accidentally damaged. Maintenance of the generator is simple requiring a discharge to 50% SOC and recharge once every 3 months.
I am thoroughly impressed with the build quality, performance and ease of use of the Jackery PS1000 as a source to power a typical astro-imaging session through a long night under dark skies. With the option to recharge within 7hrs by AC outlet and 8hrs by twin solar panels, if not less, I can look forward to eliminating those heavy lead acid batteries and avoid annoying my friends with my generator running through the night. The biggest downside to the PS1000 is its price. However, when I look at the cost of two 75Ah AGM batteries needed to match the Jackery's power, plus a quality pure sine wave inverter, MPPT charge controller for solar charging, power meters, USB charging sockets, cases, etc. I believe the cost of a DIY system easily exceeds $600 not counting the assembly effort. And one still has to carry two 50lb home built power supplies and connect them in series. Another consideration is that the Jackery can double as a backup generator in case of a power outage. The PS1000 will keep my refrigerator running for 9hrs before needing a recharge and, unlike my Yamaha generator, I can use it inside my house. For those with lesser power needs, say 40-60w the $499.99 Jackery 500 would be a lower cost option to achieve a 7-8hr imaging session. And for visual observers, the much less expensive 160 and 240w models would be more than sufficient for their power needs.
I gave the folks at Jackery feedback on how they might make their generators more user friendly to the astronomy community. First, they might consider a 5.5mm x 2.1mm or an Anderson Power Pole DC output in addition to the cigarette adapter output. Or they could supply a cigarette adapter to 5.5mm x 2.1mm or Anderson Power Pole extension cable to make it easier to for us to connect the Jackery to our equipment. However, it was easy to find a cigarette to 5.5mm x 2.1mm power cord on Amazon that serves the purpose.
The Jackery generator can be recharged with one or two of the Jackery Solar Saga panels in parallel or, with an MPPT to 8mm adapter with any solar panel under 30V and 10A. I plan to do a separate review of their solar panels in another blog soon so look for that soon.
High capacity and DoD
Extremely light weight
Well designed and simple to use
Simple to add solar recharging
Single 12V output
No 5.5mm x 2.1mm or Anderson Power Pole output
500 cycles to 80% remaining capacity
If you want to find out more about Jackery's products here is a link to their official website jackery.com As a Jackery Affiliate I can earn from qualifying purchases when you link from this site and it will not cost you any more than if you linked directly on your own.
It is apparent that more and more amateur astronomers are interested in Electronically Assisted Astronomy (EAA) based upon the many posts on the Cloudy Nights forum asking for help to get started. EAA, using a camera with short exposures to view Deep Sky Objects in real time, has been around since the late 90s when the first video cameras like the SBIG STV were used instead of an EP at the focus of a telescope to greatly enhance the views of Deep Sky Objects. You can read about the history and evolution of EAA in my blog here " A History of Camera Assisted Viewing". While the CN forum is a great source of information, particularly for newcomers to EAA, that information is not organized in one compendium which is easy to access and use. So, while I still recommend anyone new to EAA to take advantage of the many experienced and helpful folks on CN, I hope to put together in a series of blogs the fundamental information needed to successfully and more easily get started at EAA.
The very first and most important question one has to answer is which type of camera, analog or digital, is best for them. For most people and most use cases my recommendation is to go digital as that is the direction things have been heading for the last 5 years and will continue to advance in the coming years. However, there are significant reasons why someone would want to start with an analog camera and we cannot simply dismiss those.
The Case for Analog
If you are a person who absolutely does not want to use a computer then your only choice is to use an analog camera. While analog cameras can be used with a computer, they also work without one which is not the case for digital cameras. An analog camera without a computer is about as simple as it gets and has the added advantage that it requires a minimum amount of power to operate since laptops tend to be very power hungry devices. The simplest configuration includes a telescope, a camera attached to the telescope in place of the EP, a small LCD monitor connected to the camera video output, and a power source with cables to connect the power to the mount, camera and monitor. If you are working in your own backyard you can use a 3-5A AC power transformer to power everything from an AC outlet. If you are working at a dark site without AC power you can use a battery to supply the necessary power. The nice thing about this simple setup is that you can use a very small, lightweight Li battery which can even be attached to the scope along with the monitor. Analog cameras use less than 400mA of current, a 9" LCD monitor less than 300mA, and a Celestron SE, AVX or CGE mount will use less than 500mA. So an 8.3Ah battery like the one from Talentcell that I use for my simple setup will last an entire night or two before needing a recharge. This type of setup is often used for family viewing or Public Outreach events where several people at once can view the object on the display screen while the astronomer discusses interesting facts about the Deep Sky Object. It is also useful for anyone with a seeing impairment since the image can be displayed on as large of a monitor as one desires. I have used a 34" LCD TV for my public outreach but that requires a bigger battery and a DC to AC inverter to operate.
The back of the analog camera has a 12VDC power input, a video output to send the images to the display and a set of 5 buttons which are used to adjust the camera settings. There is typically another input called an Auto IRIS which is not used unless the camera is setup to use this input for either hand control or computer control of the camera menu. Otherwise the camera menu is accessed and controlled by the 5 small buttons on the back of the camera while watching the On Screen Display (OSD) of the menu on the LCD display. The video out uses a BNC connector so it is necessary to have a cable with a BNC connector on the camera end and an RCA connector on the other end to connect to a display device.
An example of an OSD is shown here. Many analog cameras are simply re-badged security video cameras, while others are security cameras with a few modifications such as increased exposure times and cooling of the sensor to reduce background noise. That means that the camera menu is designed for security applications and not for astronomy. So the menu is not intuitive and it takes a bit of a learning curve to understand how the settings apply to an astronomy application. Also, the menu consists of many layers which are accessed by clicking on one item and finding an expanded display hidden within. This can be confusing to some people at first but eventually becomes rote. It also takes some time to learn which settings need to be adjusted and what values for these settings are typical. Suppliers of these cameras offer guides for typical settings to get you started. And, you can read my blog on de-mystifying the OSD here: "Making Sense of Video Camera OSD Menus".
As I mentioned, an analog camera can be used both without and with a computer. There are software programs, some free, which can be used with the Mallincam video cameras like the Xtreme and Xterminator to control the camera menus and to capture and display the video image. For this to be possible the camera has been modified to connect to the computer. This is done with an RS232 cable connected on one end to the computer control input on the camera and on the other end to the computer through a USB adapter like the Keyspan from Tripp Lite. This replaces the buttons on the back which can be tricky to manipulate in the dark, with gloves, especially as the scope rotates about the sky and the orientation of the buttons changes.
While computer control of the camera is very useful, the biggest advantage of the computer is the ability to use the same software to enhance the image by using a live image stacking feature. Stacking is done in the computer as it takes successive image frames from the camera, aligns them and combines them into a stack during a live viewing session. As each new frame is added to the last, the image improves as background noise is reduced and more detail begins to emerge. This provides an enhanced live view of Deep Sky Objects. To connect the video output of an analog camera to a computer a digital capture device is required. This takes the analog signal from the camera video output, digitizes it and sends it to the USB input of the camera where the software recognizes it for display, stacking or capture. While there are many of these devices out there it can often be a challenge to find one that works. The one I have used religiously without any issues is the Pinnacle Dazzle device. While more expensive than others it just works.
It should be noted that digital cameras can also use a computer both for camera control and live stacking. In fact, when used with a computer a digital camera requires only one cable for both power, control and viewing compared to 3 for an analog camera.
With the two suppliers of the CCDs used in analog cameras having decided to stop production in favor of CMOS sensors used in digital cameras there are just a few suppliers of analog cameras still available. You can still get the Xtreme and Xterminator from Mallincam and the much less expensive Revolution Imager II from a number of different suppliers. The Revolution Imager II does not come set up to use computer control but does come with a hand control which simulates the buttons on the back of the camera making it much easier to manipulate the OSD and also allows one to do this remotely. There are many options of older, but very good, analog cameras which can be found on the used camera market. In summary, you would choose an analog camera if you really do not want to use a computer or want the option to use it both without and with a computer.
The Case for Digital
I recommend a digital camera for anyone just starting out. The era of analog cameras is waning and there will not be any new entries. On the other hand, new digital cameras become available as new CMOS sensors are released. The digital cameras available today provide much better images than any of the analog cameras. That is because digital cameras use sensors with many more pixels, between 1 and 61 Mpixels, compared to analog cameras which have less than 0.6Mpixels. Most digital cameras used for EAA have between 11 and 16 Mpixels . This combined with the fact that digital cameras use much smaller pixels than analog cameras, 3.75 to 4.6 microns compared to 8 to 9 microns, results in much higher resolution and a much larger field of view from digital cameras.
In addition, the pixels in digital cameras are square whereas they are slightly rectangular in analog cameras. Between the size and shape of the pixels, digital cameras produce much rounder and pin point stars. Also, video sensors tend to produce a dark halo around stars resulting in a "raccoon eye" appearance for the stars viewed with a video camera. Putting this all together, the images from digital cameras are far superior and more natural looking than from the best analog cameras.
Another big advantage of today's digital cameras is their extremely low read noise, on the order of 1.5 electrons. This helps with stacking since there is no disadvantage in taking many very short exposures to stack instead of few long exposures. This stacking strategy is very common as the short exposures reduce demands on the quality of the polar alignment and tracking precision. Shorter exposures also mean that field rotation, i.e. apparent rotation of the stars as the earth turns on its axis, is much less of an issue. This makes it much more practical to get by with an Alt-Az mount instead of requiring the use of a more expensive EQ mount.
In contrast to analog cameras, digital cameras require only a single cable to connect to a computer. This USB cable provides power to the camera, allows the computer to control the camera settings and downloads the image from the camera for display and capture on the computer. Like analog cameras these digital cameras use less than 500mA of current. If the camera has a cooler for the sensor a separate power cable identical to that for an analog camera is necessary. Power from an AC transformer or DC battery capable of supplying 3-5A is required to handle the current load.
While the image from a digital camera is naturally displayed on the computer screen, it can be shared on a 2nd, larger monitor for viewing by a group such as for Public Outreach. With the right software the image can also be wireless displayed on a tablet as well. Of course, the additional monitor will require power as well.
Many digital cameras come with their own proprietary software designed to provide camera control and include features to live stack images and even process images like in traditional astrophotography but on the fly while watching the image improve with time. Sharpcap is a more universal software program which works with most cameras either natively or through an ASCOM driver. It provides a seamless interface to the camera. The good thing about Sharpcap is that it is free, although there is a pay version which has lots of useful additional features. Sharpcap does have a steep learning curve, but it is written specifically for astronomy cameras so it is much more intuitive than the OSD menus of video cameras. Plus there is a well written manual and some on line tutorials to help one get started. Some of the proprietary software is easier to master quickly but may lack many of Sharpcap's added features. While Sharpcap will also work with analog cameras it cannot control the camera settings.
The other important point to consider in choosing between analog and digital cameras is your future intention. If, like so many who practice EAA, you think you would like to try astrophotography in the future, you will want the higher image quality and wider field of view of a digital camera. There is no comparison between the best images taken with an analog camera and an average image taken with a digital camera. In fact, with a program like Sharpcap, one can do both live stacking for live viewing while also saving the individual images to be used later for traditional astrophotography processing.
So, unless you need to go computerless, I strongly suggest getting a digital camera.
Next issue of "Beginning EAA" will address Mounts.
You can find some of the products shown in this blog along with some others I would recommend in the links provided below. I only list products which I use myself or know to work well. As an Amazon Associate I can earn from qualifying purchases through my site with no additional cost to you. This helps to defray the cost of this website.
Last year I purchased a SB MyT telescope mount to use when I travel to dark sites. The one annoyance to me with SB mounts (MyT, MX+, ME) is the fact that they are designed to work with 48V instead of 12V like almost every other mount along with cameras, focusers, filter wheels, heaters, coolers, etc. This is not a problem when one has AC power available as the mount comes with a very good 110VAC to 48VDC transformer. However, one seldom has access to AC power in the field. While using an DC to AC inverter is an option, inverters are an inefficient way to power a mount especially considering that power out in the field can be a precious commodity.
Software Bisque recommends the 56VDC EGO battery for use with their mounts in the field because their mounts can operate at voltages between 48v and 60V. But again, since almost every other piece of equipment we typically use for astronomy works on 12VDC, I prefer not to add another battery type, to the list of equipment I need to carry with me in the field. And the EGO battery, charger and SB adapter are fairly expensive.
The solution for me and many others is to use a DC-DC voltage boost converter which will take a 12VDC input (actually many take a range of input voltages) and convert this to 48VDC output. This allows me to stick 12VDC power for all of my power needs in the field. There are quite a few different converters available on Amazon for ~$15 to $30. I initially purchased the SMAKN for under $30. The MyT AC transformer supplies a maximum of 1.6A at 48V or 77W so this converter is more than sufficient for the application.
The manufacturer lists the following features for this unit:
1. Embeded Smart Chips provide protection from (1) Over current; (2) Over heating; (3) Short Circuit; (4) High voltage
2. High conversion efficiency and stability with synchronization rectification technology. Up to 95% efficiency.
3. SMT technology
4. Aluminum casing with silicone seal for waterproof, dust proof and anti-shock performance.
The input wires, red + and black -, are 14 AWG while the output wires, yellow + and black -, are 16 AWG as the input current will be 4X the output current in proportion to the voltage boost of 12V to 48V.
I first tested this on the bench with a dummy load to measure the voltage output of the converter and to make sure it was a steady 48V and that the unit did not overheat under extended use. The output of the converter is 48.5V which compares well with the no load output of the SB AC transformer of 47.9V. The converter does not get hot, but does get slightly warm to the touch under extended use. The voltage remained steady within +/-0.3V during extended testing. I was also able to measure the efficiency of this unit to be 95-96% in line with the manufacturer's specs.
Since the converter comes with 2 pairs of pigtail wires I had to decide how to connect the input of the converter to my power supply and the output to my mount. I considered hard wiring the pigtails to the appropriate cables on either side, but then decided to use Anderson Power Pole connectors instead. You will need the 30A version connectors because of the larger gauge of the power input wires. I ordered a 14AWG cable with Anderson Power Pole connectors on one end and a 2.5mm x 2.1mm connector on the other end for the connection between the power supply and the DC-DC converter. For the output, I made my own cable with 16AWG wire and 30A Anderson connectors on one end and a locking 5.5mm x 2.1mm DC connector on the other end. I attach the DC-DC converter to the leg of my tripod and run the wires from there to the power supply and up to the mount.
Since I like to have spares when it comes to any critical component that can fail in the field, I purchased a slightly different converter, the 3A, 144W version from Aweking for ~$25, as the backup. At 144W this is still more than sufficient for use with the MyT. Looking at the two side by side it is apparent that these are built in the same factory, but to slightly different specs, and sold by different distributors on Amazon. The only observable difference is the writing on the backsides identifying the current/power rating and the name of the company distributing
them. The Aweking unit performed identically to the SMAKN unit on the bench.
Next I tested each converter separately to power the mount over several different days. I supplied power to the voltage converters through my Pegasus Power Box Advanced which provides a constant view of the current and voltage drawn as well as a time log of the same and watt-hours. I could find no discernible issues running the mount with the DC/DC converter instead of the AC transformer. I am sold on this approach as a viable field power option.
While I was at it, I was able to log the power draw of the mount under different conditions. I share that here for those trying to figure out what size battery they need to power the MyT. I am using a Celestron C11 Edge with a Stellarview 50mm guide scope mounted with an ADM rail along with an ASI1600MC camera, a SSAG guide camera and Celestron motorized focuser. Total weight should be around 40lbs and is well balanced. Tracking draws 12-16w of power (0.9 to 1.25amps at 13.25V) depending upon the orientation of the OTA. Slews in one axis consume 25-35w (1.9 to 2.6 amps at 13.25V) and high speed slews in both axes take as much as 62w (4.9 amps at 12.7V). Hopefully this is helpful data for others wanting to use their MyT in the field with a 12V battery.
You can find the products listed in this blog in the links provided below. I only list products which I use myself or know to work well. As an Amazon Associate I can earn from qualifying purchases through my site with no additional cost to you. This helps to defray the cost of this website.
I have been using my faithful Celestron CGE mount for nearly 11 years since I got back into astronomy in 2008. I originally bought the CGE in a package with my trusty C9.25" SCT and both have performed wonderfully for me over the years. When I got aperture fever and bought a C14 Edge I also bought a Software Bisque MX mount to handle the bigger load. The MX has its home in my backyard observatory and that is where it will stay as it is too big for me to take to dark sites. However, I did take my C14 with me into the field mounted on the CGE. Despite the fact that the C14 is too heavy for the CGE I was still able to practice camera assisted viewing without too much trouble since most exposures were very short. The combination made for an amazing short exposure EAA rig bringing out great detail and color in short order, especially using the Hyperstar at f/1.9.
However, as time went on and I began to get the astrophotography bug it became clear that the C14 was not suited to the CGE. Oh, I could get some decent images from time to time with the pair when I used my Hyperstar and did not push the exposure too long. But I would more often than not get noticeable star trailing. At the same time it became clear to me that the C14 was getting much too heavy for me to carry into the field. I could no longer attach it to the CGE without help. So, as I wrote in a blog here last Nov, I finally sold my C14 and bought a C11 Edge in replacement. At 28lbs, the C11 is not light, but it is much lighter than the 46lb C14. And I still have a large aperture scope in the C11 to pursue my interests in astrophotography.
It was also clear to me that the time had come to move on from the CGE even though it is still a wonderful mount for its class. The C11, especially with added accessories would be pushing the load limit of the CGE. So I decided to follow the MX at home with a MyT for field use. This way I could concentrate on The Sky X as the software to run my mount whether at home or in the field and optimize my understanding of all of its features rather than switching back and forth like I had been with the NextRemote and TSX software to date.
I ordered the MyT in Feb along with its corresponding tripod and received them both in March. Fortunately I purchased both before a substantial price increase of the mount. With the Covid virus shutting down all star parties I set up the mount with the C11 inside my backyard observatory. To simulate field conditions I used the tripod on the wooden floor of the observatory instead of using my pier. Not ideal for vibrations but good enough for testing. While the mount is still not light at 34lbs, it is still quite manageable. And since the tripod sits lower to the ground the lift is not all that high. The tripod itself is very light and compact.
Even though I had been using TSX since 2012 there was much I found that I really did not understand until I started using it with the MyT. My first objective was to get a TPoint model and accurate polar alignment. I found a couple of good YouTube video tutorials to help by Charles Walker www.youtube.com/watch?v=4pbgJ24_01I and another one by Richard Wright www.youtube.com/watch?v=6cy9pKSLwXk&t=5s . I highly recommend either of these to help walk you through the process, especially since the manual has multiple different descriptions which can be very confusing to the beginner. While I had done TPoint models before, I really did not understand how to get the best out of them until I watched these tutorials and tried it myself.
The other thing that was new with the latest version of TSX was support for my ASI camera which was not there in the previous Camera Add-On. This meant that I could do an automated TPoint run which is light years ahead of doing it manually. Another improvement is the addition of the Accurate Polar Alignment feature which is run after the TPoint model and Super model are complete. The best way to describe it is that it is pretty much the same as the Celestron All Star Polar Alignment which slews to a star, allows you to center the star with the hand control, then moves to the location where the star should be if accurately polar aligned requiring you to use the mechanical Alt and Az adjustments to re-center the star and completing the Accurate Polar Aligment. The MyT behaves so much better with the mechanical adjustments than the CGE. There was a lot of cross talk between the two adjustments on the CGE making it difficult to get the star precisely center. But with the MyT there is virtually no cross talk between axes, which is what I expected when I shelled out $6K for this mount. With this done I have been able to get 90 to 120sec unguided images at f/10 without noticeable star trailing.
I still have a lot more to do such as PEC training, learning to use the automated focusing application in TSX and then guiding. But with Covid it seems that I have time to work on each of these one by one in no particular hurry. So far I am happy with my decision to switch to the MyT for field use. My CGE is still available for a second solid mount if needed. Now all I need is for the star parties to return so I can take this new rig out for a test spin.
Never Over-Tighten Your Hyperstar
I used the Hyperstar almost exclusively on my C14" Edge telescope with great success for years. Then one time I found that the Hyperstar would not unscrew from the secondary holder. No matter what I tried the Hyperstar was firmly attached to the secondary holder threads and would not come off. In fact, the more I tried to entice the Hyperstar loose I only succeeded in making the secondary holder spin in the corrector plate. Oh boy! What now? I reached out to Dean at Starizona who was a great help in solving my problem. He explained that the gasket that Celestron uses between the inside of the corrector plate and the secondary holder does not have sufficient grip and slips if the Hyperstar is tightened too much, as it was in my case. The solution, remove the corrector plate to get access to the backside of the secondary holder to release the Hyperstar. Once done, just replace the original gasket with a stickier one from Starizona and re-assemble. Well I did that but apparently I did not get the corrector plate centered on the primary mirror as well as I should have. How did I know that? Just look at this image I took of M33 and you will see that the stars in the corners are elongated in the direction of center indicating a collimation problem. Adjusting the secondary using the three screws was not sufficient to improve the collimation since the problem was that the secondary was no longer centered on the primary mirror. I read on CN about a technique using the circular rings formed by the primary mirror, baffle tube, secondary mirror and corrector when you look down the center of the optical tube as a guide to getting the corrector plate centered. The objective is to adjust the corrector plate using the screws on the outside of the optical tube (for Edge only scopes) until the ring of the corrector plate is centered. I tried this but found it too difficult to maintain a steady enough line of sight down the center of the tube to be certain how much I needed to adjust the corrector. I even tried setting up my iPad on a tripod to photograph the set of rings as shown in a YouTube video. But even this was not very successful for me. Apparently, this method does work for many people, but it wasn't going to work for me.
The moral of the story ... snug is good enough for the Hyperstar!
The HoTech Laser Collimator to the Rescue ... Not Quite Yet
That led me to purchase a used HoTech Advanced CT Collimator on Cloudy Nights. The HoTech kit consists of a collimator plate, a Reflector Mirror with removable cap and a tripod adapter. There are four lasers on the back side of the collimator plate, one in the center and 3 at 120 degrees apart at a radius of several inches from the center. The laser in the center provides a cross-hair pattern for alignment of the plate to the telescope primary mirror. The 3 other laser provide parallel beams of light to simulate a distant star. The collimator plate has concentric alignment rings on its face for accurate collimation of the scope. The tripod adapter is used to attach the collimator plate to your own tripod and provides tilt of the collimator plate in two axes. The Reflector Mirror is inserted into the visual back or focuser to reflect the laser beams back to the collimator. If using the HoTech to collimate an SCT without Hyperstar this is all that is needed. When collimating with Hyperstar the optional Hyperstar upgrade kit is required as discussed below.
Before attempting to use the CT Collimator I read a CN thread which indicated it was a good idea to check that the lasers on the collimator were themselves collimated before attempting to collimate the SCT. The thread provided a convenient method to do that using a paper target with a cross hair, a circle and 3 spots 120 degress apart where the lasers are positioned on the HoTech Collimator. The procedure is described here and works quite well.
Using this method I came to the conclusion that one of my lasers was slightly off collimation. In principal, having found the offending laser I could adjust the laser myself to get it back in collimation. However, I was concerned that it was more likely that I might make it worse so I decided to send the collimator back to HoTech for adjustment. My only cost for the service was the postage. When I got the collimator back I set it up in my garage with the same paper target and verified that all three lasers were lined up where they should be.
While waiting for my collimator to be aligned at HoTech I came up with another method to check the laser alignment using a small mirror instead of the paper target. Lining up the HoTech collimator 15 feet from the mirror and square to it enables the 3 laser spots to reflect off the mirror back onto the collimator. If the reflected laser spots all reflect back onto the lasers on the collimator, everything is in alignment. The advantage of this method is that the distance is effectively doubled providing greater precision.
If you buy the HoTech Advanced CT collimator new you should not have this issue, but it is probably a good idea to check either using the paper target on the wall or the reflection from a good mirror. The originator of this CN blog insisted that I should not use a mirror as imperfections in the mirror would throw off the lasers. I understand that argument but if the reflected laser spots return to their origins as they obviously do in the image below after David at HoTech re-collimated the lasers, imperfections will not cause out of alignment lasers to appear in alignment.
Mastering the HoTech Advanced CT Collimator
Having certified that my collimator was in collimation I proceeded to the task at hand, to collimate my 14" SCT. Anyone who has used one of these will tell you that the initial step in the process is the most time consuming, tedious and most confusing step. And it is the most important step to get right. Once you get this done correctly, the rest is easy. Conceptually the first step is simple. Get the CT collimator plate in the same plane and on axis with the primary mirror. That is done by first attaching the HyperStar Reflector Mirror Assembly to the Hyperstar. The Assembly consists of an adapter ring, Reflector Mirror and a target cap. Next attach the collimator to a tripod with the included holder. The holder provides tilt adjustments along two axes which will be used to help align the collimator to the primary mirror.
The following steps are performed with the collimator switched to Mode 1 using the center laser only to shine a cross hair pattern onto the telescope. Upon reflection from the primary mirror, this produces a clipped cross hair pattern on the collimator plate as seen in the image above. Next, adjust the height and distance of the collimator relative to the scope so that the cross hairs are centered and symmetric to one of the rings on the collimator. It is not necessary that the tips of the cross-hairs fall exactly onto one of the rings on the collimation plate, only that they be symmetric to the center of the plate. If the room is dark enough, you can also see a diffuse doughnut of red light from the laser collimator. Either the doughnut or the cross hairs can be used to do the alignment. Once either the cross hair or the doughnut is aligned, both will be aligned. I should note, that you will also move the telescope up and down or left and right to help align the collimator to the primary mirror. As the instructions say, repeat this process one or two more times but with smaller adjustments to get the alignment as spot on as possible. Also, it is best to set the collimator as far away from the front of the telescope as possible for higher precision. Typically it should be outside the Back Focal Length which is the point where the cross-hairs converge to a spot in the center of the collimator.
You will notice that the inner edges of the cross hair (and doughnut) are clipped. This is due to the shadowing of the Hyperstar (or secondary). Likewise the outer edges of the cross hairs define the outer edges of the primary mirror.
I should note that it is much better to do this process with the scope pointed upward, say 45 degrees, as it would be while observing. The weight of the mirror will cause a slight shift in position inside the optical tube when elevated which will change the collimation slightly if this procedure is done with the telescope pointing horizontally. I did this and found that unless you have a very tall tripod or a 8" and smaller SCT you will have to put the tripod on a table and tilt the collimator to the same angle as the scope. When set up like this, the process is even more confusing in terms of moving the tripod around to get co-planar alignment of the collimator and the mirror. But, eventually I succeeded. Having aligned the collimator plate to the primary mirror the hard part is done. You may have to re-check that you have not disturbed this alignment in later steps and re-adjust if needed.
The next step is to make sure that the Hyperstar (or secondary if not using the Hyperstar) is centered on the primary mirror. Switch to Mode 2 which turns on the three lasers at 120 degree angles around the collimator plate. This creates three laser spots on the Reflector mirror target cap. Adjust the telescope focuser until all three dots converge into a single dot. If three spots are not all visible on the Reflector mirror target cap you will have to go back one step to realign the collimator to the primary mirror. Next, remove the Reflector mirror cap to allow a second smaller cross hair pattern to reflect from the Reflector mirror onto the corrector plate. This cross hair shows the tilt angle of the Hyperstar focal plane to the primary mirror. Adjust the push-pull pins on the Hyperstar to center this cross hair on the corrector plate.
The last step is to center the Hyperstar on the optical axis of the primary optical axis. Put the Reflector mirror cap back onto the Reflector mirror. The three laser spots should still be converged into a single spot. Next, this spot needs to be centered on the Reflector mirror cap. This is done on an Edge by loosening the screws on the front of the optical tube which hold the corrector retaining ring in place and then making use of the 3 adjustment screws on the outside of the optical tube to center the inner edges of the cross hairs on the same circle. If you do not have an Edge, you have to adjust the corrector manually until the secondary is properly centered.
This completes the collimation process with the HoTech Advanced CT Collimator. The final step is to do a star test on a night with good seeing. Minor adjustments of the Hyperstar push-pull pins may be necessary to fine tune the collimation using the standard procedure for star collimation.
When not using the Hyperstar, the process to align and center the secondary is different but is detailed in the HoTech Collimation manual and YouTube video which can be found in the links listed below. Also, when not using the Hyperstar, there is the added step of aligning the focuser to the optical axis. This procedure requires that the Reflecting Mirror supplied with the collimator be installed in the focuser and the secondary mirror removed so that a second cross hair pattern reflected by the Reflecting Mirror appears on the collimator screen. When this cross hair is centered on the collimator plate by adjusting the appropriate screws on the focuser, the optical alignment is complete. .
The final proof of good collimation was obtained by taking an image with the Hyperstar of a galaxy with lots of stars visible out to the edges of the field of view. Since much time had passed since I had imaged M33 to discover my collimation problem, it was no longer visible. So M101 was chosen as the test target since the FOV of the image has plenty of stars out to the edge to check for coma. As you can see in the image below, the stars are much improved at the four corners indicating much better collimation.
While the HoTech Advanced CT Collimator is both expensive and requires a steep learning curve, it works extremely well allowing collimation during the day time or on a cloudy night. Unlike a star test, it also provides the ability to check the centering of the Hyperstar (secondary) and the alignment of the focuser to the optical axis of the primary, both of which can cause problems with star shapes when they are out of alignment.
If you choose to use the CT Collimator, remember to be patient the first time you do it and use the helpful documentation in the links below. Good luck!
HoTech has made a very helpful video which shows each step of the collimation process but with the secondary mirror in place, not the Hyperstar. It can be found here: www.youtube.com/watch?v=4BDwa0RVZw0
The complete written collimation instructions with illustrations, for both the Hyperstar and non-Hyperstar setups can be found on the "Helpful Links" page of this web site.
There is also a CN thread showing a clever homemade jig to help make the collimation process easier which can be found here:
There are many different names used to describe the activity of using an analog video camera or a digital USB camera to enhance the view through the lens or reflected from the mirror of a telescope. Electronic Assisted Astronomy or, EAA, is probably the most commonly used name and is the name used for a popular Cloudy Nights forum. But it is in my opinion a bit too general since the "Electronic" part of the name could simply mean a tracking mount, Night Vision equipment (as it does for the CN forum), some form of computer control, a WiFi connection, etc. The term "Near Real Time Viewing" is also commonly used since the effect is to see great detail in galaxies, nebulae, etc. in a matter of a few or tens of seconds. Video astronomy was the name used in the early days since, until recently, the most commonly used cameras by far were analog video cameras like the Mallincam, Stellcam and Samsung to name a few. But the name I like best is Camera Assisted Viewing since it goes to the heart of the activity which is to use a camera to collect light during short exposures of a few seconds or tens of seconds thereby greatly enhancing the detail seen compared to looking through the same telescope but with an eyepiece. The camera could be a video camera like those mentioned above, a digital camera like those from ASI, QHY or Starlight Xpress or even a DSLR. Often software like Sharpcap will be combined with the camera to provide on-the-fly stacking and processing to further improve what can be seen in seconds to minutes.
So, regardless of what we call this, I have wondered where and how did it all begin?
In the Beginning: Camcorders
The image of Gil Miles using a CCTV in 1961 to view the moon live on a TV screen signals the possibilities which were to come to fruition in the coming decades. Video astronomy would not only allow amateur astronomers to observe much more than they could with an eyepiece, they could do this in more comfort and they could simultaneously share the view with others. This particular photo is amusing when one notices the formal attire Gil is wearing while comfortably seated in his armchair. We have come a long way in the last 58 years in more ways than one.
It was not until Sony introduced the first consumer camcorder in 1983, the Betacam, that video astronomy finally was within reach of the average amateur astronomer. With the aid of a camcorder, armature astronomers were able to enhance their views of the moon and the planets and capture video to be viewed later or processed to make pretty images. However, because of the size of these early camcorders (they generally also housed a VHS or Beta tape recorder) they needed to be mounted onto a tripod or hand held at the eyepiece of a telescope for afocal imaging. Over time camcorders became smaller and lighter and easier to use with a telescope and some had detachable lenses so that the camera could be mounted at prime focus of the telescope. But camcorders were still limited to bright objects like the planets, the moon, double stars and lunar occultations because of their low light sensitivity (1-5 lux), short exposures (1/60th sec.) and lack of manual control of the exposure and gain settings. In addition, camcorders had auto focusing, which made them even more of a challenge to adapt to astronomy. Indeed, Dennis di Cicco reported in his review of the Canon L1 camcorder in Sky &Telescope April 1992 that he could only record a trace of the bright core of the Orion Nebula through a 200mm/f1.8 lens. Nonetheless, intrepid amateurs showed the advantages of adapting camcorders for astronomy as the age of Camera Assisted Viewing began.
In 1994 the first commercial webcam, the QuickCam, was introduced for $99. In contrast to camcorders, webcams were not only inexpensive, they were also much smaller and lighter and more easily adapted to astronomy. And, they came with a USB cable and software for easy connection to and control by a computer. The QuickCam and the Philips ToUcam were two of the more popular early webcams using Sony's 1/4" ICX098BQ CCD detector with 350K total 5.6um square pixels. In contrast to the camcorder, webcams had a maximum exposure of 200 msec which was nearly an order of magnitude longer than that of a camcorder. While offering the amateur astronomer improvements over the camcorder, the webcams did have their limitations. Since they were designed for terrestrial use, they required mechanical modification to enable attachment to a telescope. This involved surgery to remove its lens and add a c-mount adapter. And the small size of the detectors used in webcams greatly limited their field of view, making it sometimes difficult to find and center the object of interest. Ultimately, with sub-second exposures (0.2 sec.), small chips (1/4"), small pixels (5.6 microns), poor sensitivity (initial Lux values of 10 to 20), webcams were limited to bright celestial objects like the moon and the planets. Despite this, webcams quickly made their mark as premier planetary imagers. By taking advantage of their 60 to 90 fps image capture rates amateurs could collect thousands of images of a planet in a few minutes which they would post process later. Using free software like Registax to automatically select and align the better images produced during brief moments of exceptional seeing, amateurs were able to produce images rivaling those of professional astronomers with much larger and better telescopes only a decade earlier. As this approach gained traction, the Quickcam and Unconventional Imaging Astronomy Group (QCUIAG) was formed in 1998 as an online forum where new methods, cameras, modifications and images could be shared among like minded video astronomers.
It did not take long for some enthusiasts to push the envelope and figure out how to modify these webcams to achieve longer exposures and begin using them to successfully view and image some of the brighter Deep Sky Objects (DSOs) like star clusters, galaxies and bright nebulae. In 1999 Dave Allmon found that by clipping a single wire in the Connectrix webcam he was able to take long exposures which he demonstrated with images of 5 sec to 180 sec duration of the Andromeda galaxy. Unfortunately this capability was a quirk of the Connectrix camera and could not be applied to other Webcams. Then in the summer of 2001 Steve Chambers is credited with pioneering a series of modifications to a wide variety of webcams allowing long exposures, replacement of the standard CCD with larger and more sensitive CCDs and disabling of the amplifier to minimize noise. While amateur astronomy is flush with do-it-yourselfers, not everyone has the skills or desire to make their own modifications. Enter the commercially modified webcams from the likes of Atik (ATK-1C, ATK-2C), SAC (SAC7, SAC7b), Celestron (NexImage), Meade (Lunar and Planetary Imager and Deep Sky Imager), and Orion (Starshoot Solar System and Deep Space). The ATK-1C and NexImage were commercial modifications of the ToUCam. All of the commercially modified webcams were designed with housings to fit into standard 1 1/4" eyepiece holders, many had passive cooling designs and some even had fans to better reduce the appearance of warm pixels. They also came with larger chips for larger fields of view and larger pixels for improved light sensitivity. And all provided longer exposures than unmodified webcams pushing practical exposures into the range of minutes. This finally made it possible to create images of DSOs by collecting hundreds of exposures of a few tens of seconds which could later be stacked and processed with software like Registax. See for instance, Stephen Chambers and Stephen J. Wainright, Sky &Telescope Jan. 2004. At this point it was possible to do Camera Assisted Viewing of brighter DSOs with a webcam, but this limited capability was already being made moot by the availability of integrating video cameras from SBIG, Adirondack and Mallincam leaving webcams as the mainstay for lucky imaging of the solar system rather than the key to Camera Assisted Viewing of DSOs. A complete review of Webcams and their applications to astronomy can be found in Robert Reeves 2006 book, "Introduction to Webcam Astrophotography".
As the search for ever improving capability evolved in the 90s, amateur video astronomers eventually began experimenting with low-light video surveillance cameras. While larger than webcams these cameras came with higher sensitivity, detachable lenses and c-mounts allowing them to fit nicely into 1 1/4" eyepiece holders. They were typically used with a frame grabber and a VHS recorder to capture thousands of frames which could later be stacked in software to produce excellent solar system images, some say better than what could be obtained with long exposure film cameras.
In 1994 two amateur astronomers in upstate New York, John Cordiales and Jim Barot, saw the value in these video surveillance cameras and launched their own company, Adirondak Video Astronomy. One of their first products was the Astrovid 2000 in 1996 which sold for $595. This camera used a Sony 1/2" B&W CCD, ICX038DLA, and had an exposure range of 1/60 sec to 1/10,000 sec making it well suited to solar, lunar, planetary and occulations but not DSOs. A big advantage of the Astrovid 2000 was the fact that it provided for manual adjustment of the shutter, gain, gamma and contrast through a wired hand control providing the needed control over the image settings and also making it possible to change camera settings without disturbing the telescope. David Moore published a detailed review of the Astrovid 2000 in Sky & Telescope Aug. 1999. While still not ready for DSO viewing, John and Jim would soon play a pivotal role in reshaping the nature of video astronomy.
Then in 1998 a Texas company, Supercircuits, introduced two very inexpensive video surveillance cameras, the PC-23C and PC-33C, a B&W and color model, respectively. Because these cameras could be purchased for only $80, they quickly became very popular in the video astronomy community. These re-badged Topica TP-505D/3 cameras from Taiwan used 1/3" Sony CCDs and had a maximum exposure of only 1/30 sec. Unlike the Astrovid 2000, the Supercircuits cameras had auto exposure and auto gain mading the cameras challenging to obtain the needed exposure for small, high contrast objects like the planets. In his Skywatch March-April 1999 review of the PC-23C, Rod Mollise noted the excellent views he achieved of Saturn and Mars, including a clearly defined and razor sharp view of the Cassini Division. But, he noted, " For 'real' deep sky work you do need an integrating CCD camera..." Even though these inexpensive Supercircuits cameras were not capable of viewing DSOs, they were quite capable at capturing images of the solar system and the B&W version was a favorite tool for asteroid occultations.
Similar to Topica, another Taiwanese company, Mintron, and a Japanese company, Watec, began developing and selling video surveillance cameras in the 90s. Cameras like the Watec 902H ($500) with its 1/2" Sony ICX249ALL CCD also found their way into the amateur astronomy community even though the manufacturers were not initially aware of this application for their products. But with exposures still limited to 1/60sec (NTSC) and 1/50sec (PAL) these cameras were also not useful for viewing DSOs. Nonetheless, both Mintron and Watec cameras would be key to shaping the nature of Camera Assisted Viewing over the next decade, if primarily through several innovative amateur astronomers who saw the value of this new technology.
While the 90s brought a new technology, video surveillance cameras, to the forefront of amateur astronomy, maximum exposures of 1/30 sec limited the cameras, like the webcams, to the solar system, asteroid occultations, lunar meteor impacts, double stars and bright open clusters. To take advantage of this new branch of astronomy, a Yahoo Video Astro Group was formed by Jim Ferreira in the spring 1999 providing an on line forum for discussion of video cameras and equipment for lunar, solar and planetary astrophotography, and eventually DSOs. That forum continues to this day.
Integrating Astro Video Cameras
In the Beginning: The SBIG STV
The first video camera designed and marketed for real time viewing of DSOs is probably the SBIG STV. This dual purpose guider and video camera was introduced in 1999 with with the capability to perform exposures of 1 msec to 10 min. In their 2000 book, "Video Astronomy", Steve Massey, Thomas Dobbins and Eric Douglass called the arrival of the STV a "first glimpse into the exciting future of video astronomy." The longer exposures afforded by the STV suddenly made it possible to view images of DSOs in real time without the need to capture thousands of individual frames for stacking and processing later. An exciting new age in amateur astronomy had arrived.
The key to longer exposures is the ability of the camera to integrate the light captured by the CCD over many 1/60 sec (NTSC or 1/50 sec PAL) exposures effectively creating a single longer exposure. This long exposure is stored in the camera's buffer and continuously output to the monitor at standard video rates, 30 frames/sec NTSC or 25 frames/sec PAL. When a new long exposure is ready it is transferred to the buffer and output in the video feed for viewing until the next long exposure replaces it. Thus, one can view an image continuously on the monitor while the camera takes the next long exposure.
The STV is an all-in-one system with a CCD camera attached by an electrical umbilical cord to a large control box just under 12" x 10" x 3". The camera uses a sensitive B&W 1/3" CCD sensor from Texas Instruments, TC-237. The STV gives the user manual control of exposure, gain, brightness and contrast providing the user with complete control over the camera, unlike camcorders and security cameras like the Supercircuits PC-23C and similar cameras of the day. With the STV it was now possible to view all of the Messier objects with exposures in the range of a few seconds to minutes. In many ways the STV was way ahead of its time considering that it also came with a Thermo Electric cooler, automatic dark frame subtraction to minimize noise, complete control of the camera's settings, image display and image capture with or without a computer and a feature called "Track and Accumulate". The "Track and Accumulate" feature allowed the camera to internally align and stack up to 10 frames in real time to dramatically improve SNR reducing noise and improving feature detail. The STV also had the ability to store images in the on-board internal memory for later display or download to an external computer. Optional accessories included a 5" B&W LCD monitor, color filter wheel and a focal reducer with an extension tube capable of reducing an f/10 system to ~f/6 and f/3.75. The focal reducer could also turn the camera into a wide field finder "eFinder" with a FOV of 2.7 degrees. Alan Dyer gave a thorough review of the SBIG STV in the Jan. 2001 Sky &Telescope.
However, at a price of $1995 for the base unit and $2395 for the Deluxe with the LCD display, this camera was out of reach of many amateurs who continued to look for a cheaper alternative. The STV was discontinued in 2006 due to the lack of key component availability, but used systems can occasionally be found for re-sale on Cloudy Nights.
A Couple of Guys in Upstate N.Y.: The Stellacam
In the meantime, a number of forward looking amateur astronomers were working on adapting existing security video cameras from companies like Mintron and Watec for astronomical use. As mentioned above, Adirondak Video Astronomy was one those and although their Astrovid 2000 was not suitable for real time viewing of DSOs, things changed in the fall of 2001 when they introduced the Stellacam for $595. While this camera had the same CCD as the Astrovid 2000 the key difference was the capability to integrate up to 128 x 1/60 sec image frames for a maximum exposure of 2.1 sec. This extended exposure capability, while not as long as that of the STV, was sufficient to make it possible to view many DSOs in real time that were not possible previously with cameras like the Astrovid 2000, Supercircuits PCs, modified webcams and camcorders. The Stellacam was in reality a re-badged Mintron MTV 12V1 with the IR filter removed to increase sensitivity at the important Halpha wavelength. It also had a different rear panel than the stock MTV 12V1. Instead of the 5 buttons to navigate the camera on screen menu, the BNC video and S-Video connectors, a power input port and a green LED, the Stellacam had a single multi-pin connector for the cable to connect to a wired hand control. Unlike the more sophisticated hand control for the Astrovid 2000, the Stellacam's hand control was a small metal box with five buttons and a resistor network inside so the user could to emulate the camera menu buttons on the back of the camera body. This box also had an input for camera power and a BNC connector for the video output from the camera. This enabled a single wire from the camera to the observer several feet away. While the STV heralded a new world of possibilities, the Stellcam, even with its limited exposure, opened up that new world to many more astronomers at 1/3 the cost of the STV.
The Stellacam was followed by the Stellacam EX in 2002 ($695) and the Stellacam II ($795) in 2003 further improving the depth and detail of DSOs which could be viewed in real time. The EX was another re-badged Mintron security camera, the MTV12V1Ex. It was still limited to 2.1sec exposure but with the more sensitive 1/2" Sony ICX248 CCD it could provide much more detail than the Ex. It came with the same hand control as the non-Ex camera. In his review of astronomical video cameras available at the time in Sky & Telescope Feb 2003, Johnny Horne noted that both the Stellacam and Stellacam EX were "sensitive enough to put the Triffid Nebula directly on a TV screen in real time."
With the Stellacam II, Adirondak switched manufacturers from Mintron to Watec, re-badging the Watec 120N which had the even more sensitive Sony 1/2" ICX418 CCD. But the biggest improvement with this camera was the capability to increase internal stacking to 256 frames for a maximum exposure of 8.5 and 10.2sec, respectively, for the NTSC and PAL versions of the camera. The Stellacam II was supplied with a much more sophisticated wired hand control than either the Astrovid or the Stellacam Ex. Most likely the new hand control was manufactured by Watec itself, since one could purchase the exact same camera and remote directly from Watec. This remote had rotary knobs for adjustment of the exposure integration (1X , 2X, 4X, ... 256X) and Gain along with a sliding switch to change the Gamma. An optional wireless hand control was available instead of the wired hand control eliminating one extra wire from the camera to the observer.
The last of the Stellcam series, the Stellacam III ($1295) based on the Watec 120N+, was released in 2006. It had the same CCD as the Stellacam II but now had an unlimited maximum exposure which made the Stellcam III the ultimate an astronomer could ask for. Now, the ability to view DSOs was more limited by the mount polar alignment, tracking capability and light pollution rather than the upper limit of the camera exposure. The Stellacam III had the same wired and wireless hand control options as the Stellcam II. But it also introduced Thermo electric cooling (TEC) of the sensor with the addition of a Peltier cooler like the STV to help reduce thermal noise. In his 2005 book, "Visual Astronomy Under Dark Skies", Antony Cooke called the Stellacam line of cameras "true astronomical video pioneers."
Around 2010, the Stellacam line of cameras was taken over by John Lee's CosmoLogic Systems. Cosmologic had provided the Peltier cooling for the Stellacam III and the wireless remote for Adirondak's camera. When Cordiales decided to leave the business, Lee stepped in, at least for a short time. It seems that the change in ownership, the fact that Stellacam never introduced a color camera and stiff competition from another innovative amateur astronomer ultimately led to the disappearance in the Stellacam line earlier this decade. Used Stellacams can still be found in the Cloudy Nights or Astromart classifieds, but have long since been supplanted by much more capable and even less expensive video cameras.
A Guy Even Further North Joins the Fun: The Mallincam
In the meantime, up in Canada a fellow named Rock Mallin began tinkering with video cameras for astronomy in earnest in 1994 and introduced his 1st commercial camera, the Mallincam I (MC I) in 1999. This first camera also used a B&W 1/3" CCD and had a maximum 1/2 sec. exposure which limited its use to the solar system and lunar occultations. It was not until late 2002 or early 2003 that the Mallincam II was introduced with the ability for exposures of 2.1 sec, long enough to display many DSOs in real time. It used the same Sony CCD as the Stellacam and the Mintron 12V1 and appears to be a modified version of the Mintron. It is likely the MC II that Terence Dickenson reviewed in Sky News Nov/Dec 2003 remarking that " On the deep sky, the Mallincam really shines." The MC I and MC II appear not to have widespread distribution and may have only been used by a handful of amateurs in Canada. But this would change dramatically as Rock released a succession of analog video cameras with key improvements over the next decade. His MC II Color camera introduced in late 2003 or early 2004 was the first commercially available long exposure astronomy video camera with color capability and a major game changer for deep sky camera assisted viewing. The MC Hyper in 2004-2005 extended exposures up to 12 sec with its "hyper" circuitry. The Hyper Plus introduced in 2005 and reviewed by Gary Kronk in Astronomy, July 2010, extended the maximum exposure to 56 sec and appears to be the first Mallincam camera with Peltier cooling. It is likely that with the Hyper and Hyper Plus cameras, the Mallincam line really took off. The VSS and VSS+ in 2007-2008 pushed the maximum exposure to just under 2 min. and also were equipped with a Peltier cooler. With the Xtreme in 2009 the maximum exposure was now 100 min., certainly beyond any real time viewing threshold. The B&W versions of the Hyper Plus, VSS, VSS+ and Xtreme all used the Sony ICX428, while the color versions used the ICX418, all 1/2" format. The Xterminator introduced in 2014 with the extremely sensitive Sony ICX828 CCD was the last of the new analog cameras from Mallincam. Rocks cameras ranged in price from $249 for the Micro kit to $600 for the MC Jr Pro model up to $1750 for the Xterminator. The Mallincams have been some of the most popular, if not the most popular cameras in the post Stellacam era. Many of these cameras are still available today along with a line of digital CMOS cameras for both real time viewing and astrophotography.
From Down Under: The GSTAR
While Stellacam and Mallincam were well established in the video astronomy community in North America, down under an Australian company launched by Steve Massey in 2002, MyAstroShop, began marketing its GSTAR line of astronomy video cameras. Steve eventually released 3 analog video cameras over the years, all re-badged Mintron cameras. The GSTAR EX was first with the 1/2" Sony B&W ICX429AL CCD and a 2.56 sec maximum exposure. This was followed by the GSTAR EX Color, most likely a re-badged Mintron72S85HP-EX with the 1/2" Sony ICX249AK and 5.12 sec maximum exposure. The last video camera in the GSTAR series was the GSTAR EX2 ($579) with the 1/2" Sony B&W ICX429 CCD also with a maximum exposure of 5.12 sec. It appears that all of the GSTAR analog video cameras are now discontinued but have been replaced with CMOS digitial cameras as the hobby has moved in that direction. Steve's cameras had their IR filters removed like both the Stellacams and Mallincams. Unlike the Stellacams and Mallincams at that time, the GSTAR cameras could be controlled by a computer with the free GSTAR-COM software. An optional 10 meter RS232 to DB9 cable was needed to connect the pc to the camera through the camera's Aux port. In addition to the camera shop, Steve has advanced the hobby by authoring several books, including two books on video astronomy in 2000 and 2009.
The Stock Security Camera: Mintron, Watec and Samsung
While it does not appear that Mintron actively marketed their cameras to the astronomy community, that did not stop astronomers from seeking out their latest cameras for such use. This included the MTV12V1 and 12V1-EX which were used in the Stellacam, Mallincam and GSTAR line of cameras to name a few. Other Mintron security cameras like the 12V6HC-EX color camera also found their way to the back of telescopes through word of mouth on one astronomy forum or another. In Astronomy Now Dec 2007, Ade Ashford reported that he was able to see the dust lanes in the spiral arms of M31 with a Mintron 12V1-EX attached to his 105mm f/4.2 AstroScan.
At some point, Watec began to realize that their cameras were being used for astronomy and began to advertise them as such. Their 120N and 120N+ with wired remotes were sold direct to astronomers as well as re-badged by Adirondak and sold as Stellacams. Like the Mintrons, amateurs sought out any promising camera from the likes of Watec over the years.
In 2008 Samsung introduced its SDC425 video security camera with a 1/3" color Sony CCD and the capability for 4.2 sec exposure integration for the comparatively low price of $175. In 2009 the Samsung SDC435 (later renamed the SCB200) was released with a 1/3" Sony ICX638 color CCD and an exposure of 8.5 sec for just $99. This became a very popular camera given its price and reasonable capability for deep sky viewing. The SCB4000 with the 1/2" Sony ICX428 CCD was released in 2009 for $347 and it also had a maximum exposure of 8.5 sec. These cameras have a plastic IR filter placed in front of the CCD which is easily removed since it is held in place with two small screws. The Samsung's were never marketed for astronomy and apparently never re-badged and resold to the hobby, but could be purchased direct from security video camera suppliers. They were much larger than the Mintron and Watec cameras and are still popular today, although the above versions are no longer in production.
A Late Arrival: The LNTech300
In 2013, word spread of a new, small form factor security video camera manufactured in Hong Kong and available on-line from a number of Asian re-sellers. Like the Samsung, this camera was not directly marketed to the astronomy community, but awareness within the ranks soon made it a very popular camera. That and the fact that it could be purchased for a mere $69 yet had the capability for exposures of 20.5sec PAL and 17.1sec NTSC. Not only that, but this camera had the capability to internally stack up to 5 successive images on the fly, a process called 3D-DNR, which greatly helped increase SNR and smoothed out the noise and enhanced the detail. The LNtech300 used the 1/3" Sony ICX810 and 811 CCD for NTSC and PAL, respectively. Since this camera was not sold directly as an astronomy camera, one had to either ask the re-seller to remove the IR filter glued on top of the CCD or remove it themselves, which many did. The main limitation of this camera was the fact that it used a 1/3" CCD at a time when most amateur astronomers were already used to the 1/2" format and were looking to the possibility of even larger sensors in the future. The main advantage was its low cost making it appealing to anyone just entering the hobby.
Mallincam came out with a rebranded version of the LNtech300 called the Micro Ex in late 2013. This camera was identical to the LNtech300 except in two important ways. First, the IR filter was already removed from the CCD. Second, the Micro had some internal wires spliced so that the Auto Iris connector could be used with the proper cable to control the camera menu by a computer and free SW which emulated the buttons on the back of the camera. This was a very nice feature for those who wanted to use the camera with a computer. A DIYer could easily make the same modification to the LNtech300 which many did. In fact, one can find threads on the Cloudy Nights forum for this and another modification to provide WiFi control of the camera as well.
End of the Line: The Revolution Imager
The LNtech300 was re-badged and sold along with several useful accessories by Orange County Telescopes starting in Sept. of 2015 as the Revolution Imager. It used the PAL version of the CCD, the ICX811, which provided a maximum exposure of 20.5sec. While most camera suppliers included a C-mount adapter, a power cable or power transformer and maybe a video cable with their cameras, the Revolution Imager kit was unique in the completeness of the included accessories. For $299 you received the camera with the IR filter already removed, a C-mount adapter, power and video cables, plus an external 1.25" IR filter, a 0.5X focal reducer, a 7" LCD display, and a rechargeable battery all neatly arranged in a padded soft carrying case. The user need only supply the telescope and a clear night sky. The Revolution Imager was reviewed by Rod Mollise in his Dec 13 2015 Astro Blog where he concluded that the Revolution Imager was not only inexpensive but a "very capable camera." Unfortunately the LNtech 300 supply from the Asian re-sellers was exhausted by late 2015 or early 2016 and with it the last of the Revolution Imager cameras.
Fortunately, Mike at OCT was able to source a new analog video camera by May of 2016 which he called the Revolution Imager 2. This camera comes in a square rather than a rectangular case format but with the same ICX811 sensor. However, the firmware for this camera differed from the RI I such that the maximum integration was x256 and not x1024 like the RI I. Thus the longest exposure was 5.1sec. However, the 3D-DNR allowed averaging of 6 successive frames instead of 5 which gives a 30.6 sec total average signal. The RI 2 is still available today from OCT and a number of astronomy retailers.
And Then There Were: Orion, PD, Polaris, ITE, SC2000
While the cameras mentioned so far probably account for the vast majority of video cameras used for deep sky viewing, I would be remiss not to mention some others. One of these, Orion Telescopes, marketed their offerings as the StarShoot Deep Space Video Camera I and II. Both cameras were simply re-badged Mintron 72S85HN-Ex-R color cameras with a 1/2" Sony ICX248AKL (NTSC) or 249AKL (PAL) CCD and an integration of 256X. The only difference of the DSVC II appears to be an added serial interface for computer control. Polaris USA marketed several different Mintron cameras without modification including their most popular model the Matrix (Mintron MTV12V1) and their color model the Polaris DX-8263SL, a re-badged Mintron MTV63V1. ITE appears to have sold three different cameras, the Deep Sky Pro, a re-badged the MIntron 12V1, the Deep Sky Pro EX, probably a re-badged Mintron 12V1Ex, and a color camera called the Color Eye Pro. In the U.K. Phil Dyer is still a major supplier of video cameras. These include the B&W Mintron MTV2285HC-Ex with a 5 sec exposure which he calls the PD2285C-Ex. Phil also has a color camera which is a modified Huviron (Korea) security camera with an ICX638 (NTSC) or ICX639 (PAL) Sony CCD with up to 20sec maximum exposure. Several of these cameras are discussed in Adrian Ashford's Dec 2003 Sky & Telescope article on integrating video cameras.
In early 2015 yet another deep sky video camera option came to light with a posting on the Cloudy Nights EAA forum by "photo444". He documented a DIY project to build a camera from the pc board containing the CCD and electronics which he purchased from SecurityCamera2000 for just $23. A wired remote was included which was easily attached to the appropriate points on the camera board with push on connectors. Originally, these cameras came with the typical IR filter which removes some of the useful IR light from deep sky objects. However, it was not difficult to remove by applying heat to the glass filter with a soldering iron. Fortunately, the DIY project became a lot easier when it became clear that one could request the board camera without the IR filter directly from the supplier. Then all that was required was to build a simple enclosure and attach the board camera, feed through the wire harness for the remote and connect a C-mount adapter to the face of the box. The original idea came from another poster on Cloudy Nights, "David B in NM", who had suggested it to "photo444". This board camera compared favorably in performance with the LNtech300. It used the 1/3" Sony ICX638 and ICX639 CCD and had a maximum exposure of 1024X. This camera set off a wave of similar extremely inexpensive but capable DIY board cameras. More information and images cane be found on the Cloudy Nights forum by searching "SC2000" on the EAA forum and by reading the blog on this web site do-it-yourself-board-camera-for-35.html
Its Not All Hardware: Software Plays Its Part
Indeed, while the focus to this point has been on the development of the ever improving hardware that collects the photons necessary to view deep space wonders, software may be the unsung hero that has had its own ongoing role in the advancement of video astronomy. Software's contributions can be divided into two important categories: 1) camera control; 2) image capture.
A major challenge for newcomers when trying to operate one of the video cameras is the fact that the camera settings are designed for video surveillance applications, not for astronomy. Hence, the menus can look like Greek to the uninitiated with many of the functions completely irrelevant to astronomy applications. On top of that, important camera settings can be buried several layers deep within the menu. A more in depth discussion of this challenge can be found here making-sense-of-video-camera-osd-menus.html . Fortunately, some very helpful individuals have come to the rescue and created free software which put all of the relevant camera settings in an easy to view, understand and modify format. Two such examples are the GSTAR-COM software developed for the GSTAR and Stephan Lelonde's Mallincam Control software developed for the Mallincams. Both are free and both require that the camera be connected to the pc with the appropriate cable which can be obtained from the camera supplier. These simple to navigate and effectively organized menus leave out the camera functions one would never use for astronomy and make it much easier to navigate through the control settings needed for astronomical viewing. While these programs made controlling the camera much easier they did not provide for image capture and processing.
As video cameras became more popular and amateur astronomers craved to go deeper, minimize noise, remove hot/warm pixels and save images more sophisticated software began to appear. In 2010 Robin Glover released a program called Sharpcap which was originally developed to simplify camera control and image capture for Webcams in place of existing programs like AMCAP. In 2012 Sharpcap was revised to work with additional cameras which eventually grew to include Basler, ZWO, Starlight Xpress, QHY, Celestron, Point Grey, almost all Webcams, cameras with an ASCOM driver and most frame grabbers. Sharpcap provides a simple layout with a live image along with camera controls all in a single screen view. Over the years Robin has added new features to the camera making it extremely useful for real time image viewing, processing and capture. These include on the fly dark frame subtraction, flat frame correction, image stacking, histogram adjustments, polar alignment, plate solving, focusing aids and more. There are both free and license versions of Sharpcap, with the later containing many of the more advanced features. Sharpcap may now be the most used software for real time viewing.
Chris Wakeman and Steve Massey developed a program called GSTAR-Capture in 1998 for automated and manual capture of video AVI files. It included the ability to capture single frames and had faint object enhancement features including dark frame subtraction. A revised version, GSTAR 4 Capture was released later which added a favorite object, location and equipment database and the ability to record Universal time, RA, DEC, filter used, telescope, and focal length. This version also included a live histogram, occultation time stamping plus the GSTAR-COM camera control for a compete camera control and capture software package.
Also in 2012 William Koperwhats developed the Miloslick software ($49) for many of the Mallincam cameras (Xterminator, Xtreme, VSS, VSS+, etc.). Like Sharpcap, Miloslick provides simple to understand camera controls along with a live image view. And like Sharpcap it provides image capture sequencing, on the fly dark frame subtraction, image stacking, histogram adjustments and more. Lodestar LIve is yet another similar program, developed by Paul Shear in 2014 specifically for the SX Lodestar, providing many of the same image capture and on the fly processing functions as Sharpcap and Miloslick but only for the Lodestar. Eventually Starlight Xpress (SX) bought the software and renamed it to Starlight Live and expanded its compatibility to several other SX cameras.
The Digital Revolution
In 2015 Sony announced that it would cease production of CCDs by 2017 and concentrate on the less expensive CMOS technology which was beginning to match CCD performance and is widely used in commercial digital cameras. While security camera based analog video cameras capable for deep sky observing are still available from Mallincam, Mintron, Watec, Samsung, OCT and PD, there have been no new analog astronomy cameras coming onto the market since the Revolution Imager II and it is not likely that there will be. Instead there has been steady growth of the CMOS based digital cameras from the likes of ZWO, QHY, Starlight Xpress, ATIK, Altair Astro and Rising Tech. Mallincam, GSTAR, and OCT also have new digital cameras for real time viewing as well. Almost all of these cameras use CMOS sensors and all have much higher resolution and larger sensors than the analog cameras. When coupled with the latest software like Sharpcap (and others), real time viewing of the deep sky has evolved tremendously from its roots decades ago. That history is still being written, but you can read more about the early days of this digital revolution on my blog here: the-digital-revolution-in-camera-assisted-viewing.html
The Video Astronomy Innovator Hall of Fame
If I were to make a list of those who have played a significant role in shaping the last 20+ years of amateur video astronomy the following would be my candidates.
Steve Chambers: For leading the charge for extended exposure webcams
Jim Ferreira: For creating the Yahoo Video Astro group and expanding the hobby
SBIG Team: For setting the bar in 1999 with the STV
John Cordiales & Jim Barot: For popularizing the modified security video camera
Rock Mallin: For the 1st color video camera and continuous camera innovation
Steve Massey: For his books on video astronomy and his GSTAR line of cameras
Mike Fowler at OCT: For providing a low cost video camera kit for the beginner
Stephan Lelonde: For providing one of the first camera control programs for free
Robin Glover: For Sharpcap with real time on the fly processing
William Koperwhats: For developing Miloslick SW for the Mallincam cameras
Jim Turner: For creating the live broadcast site Night Skies Network in 2009
photo44 & David B in NM: For popularizing the DIY board camera
My first telescope was a 60mm Unitron refactor which I bought with money saved from my paper route when I was about 14 years old. At f/15 this refractor was designed for solar, lunar and planetary work which I did visually from my heavily light polluted back yard in Pittsburgh, PA. Dreams of deep space objects and trying my hand at astrophotography would have to wait many decades until I purchased my second scope, a 9.25" Celestron SCT. The SCT is a versatile telescope design which can be used for solar, lunar and planetary work at its native f/10 or higher with a barlow, or for deep space objects with a focal reducer at f/6.3 and lower. My 9.25" was used primarily for Camera Assisted Viewing (CAV),or EAA. It has good optics, is light weight, provides excellent aperture/cost and mine seemed not to suffer much from mirror flop or mirror shift. I have posted many images on this web site taken with the 9.25" and a variety of video cameras. (Keep in mind that CA or EAA is not about true astrophotography but is focused on real time viewing with a camera. It is understood that images captured with a video camera will never compete with those captured with a true astrophotography camera. Instead, the images serve as a "postcard" of each DSO visited and viewed in much greater detail with the camera in real time than what would be visible with an eyepiece only).
It only took a couple of years for me to succumb to "aperture fever" and order a second SCT, the Celestron 14" Edge with Hyperstar. The C14 obviously has a much larger aperture than the C9.25 which allows it to collect ~2.3X as much light. This allowed me to get much more detail and much higher magnification when viewing and imaging deep space objects. And with Hyperstar, which my particular C9.25 does not have, the C14 can achieve a focal ratio of 1.9 providing a very fast optical system which is ideal for CAV. See the photo below of the Sculptor Galaxy NGC253 taken with a Mallincam Xtreme video camera with the C14 Hyperstar at f/1.9. The exposure time was a mere 14sec, yet the image shows amazing detail for such a short time due to the very fast optics and the high sensitivity of the sensor in the Xtreme. With performance like this I referred to the C14 as my "Big Gun". Initially I planned to use the C14 only in my home observatory since it is nearly twice the weight of the C9.25. But, darker skies called and I began taking the C14 with me to my typical star parties, GSSP and CalStar. The "Big Gun" has been my companion at nearly every one of these star parties since 2012.
As my interest in CAV led me to more traditional astrophotography with CMOS cameras like the ASI 224MC and 1600MC, the C14 was the natural choice for an OTA. As I mentioned above, it's ability to go from f/11 (the C14 Edge is native f/11 instead of f/10) to f/7 withe the very expensive Edge focal reducer and to f/1.9 with the even more expensive Hyperstar adapter, makes the C14 a very versatile scope for astrophotography. Below is one of my first attempts at traditional astrophotography using the C14 in hyperstar mode with an ASI1600MC. The image is a stack of 116 x 30sec subs with dark frame subtraction and a stretch of the data to obtain the final image.
At 46 lbs not counting any extra mounting plates, the C14 is a challenge to mount and de-mount without assistance. The fact that most of the weight is at the back end makes it even more difficult to maneuver into place. With age and after surgery on each of my shoulders, it was clear that my " Big Gun" needed a new home. While sorry to see it go, I was lucky to find a very experienced astrophotographer in my local astronomy club who could not only handle this massive scope physically, but could also put it to excellent use.
While I still have my C9.25 I was not ready to completely give up on large apertures. So I immediately used the proceeds to purchase a C11 Edge which is only slightly heavier than my C9.25. I hope to be able to use this smaller, yet fairly large scope for many years to come as I work on my attempts to master traditional astrophotography. I expect to post images with this new scope, on this web site in the near future.
The introduction by ZWO of their camera, the ASI1600, in early 2016 has been a game changer for Camera Assisted Viewing (CAV), also known as Electronically Assisted Astronomy (EAA) or Near Real Time Viewing. This camera was the first astronomy camera to use Panasonic's latest CMOS sensor, the MN34230. The 4/3 format sensor has 16.3 Megapixels (4644 x 3506), each 3.8 microns square with a total chip size of 17.6 x 13.3mm. The larger chip size has a diagonal of 22mm which provides a much larger field of view compared to the cameras commonly used for CAV . Compare this to the analog cameras from Mallincam which have less than 0.5 Megapixels and diagonals of only 6 and 8mm depending upon the camera model. Even the recent CMOS cameras like the ASI224 only has 1.2 Megapixels and a diagonal of 6mm, much smaller than the ASI1600.
And with 3.8 x 3.8 micron pixels it provides high resolution images for excellent image detail. Additionally, this sensor supports extremely low read-out noise on the order of 1 electron which made stacking many very short exposures much more practical. This reduces the demand on the quality of the polar alignment and the mount tracking for a successful CAV session. With such a large sensor and 16 million pixels, this chip supports binning 1x1, 2x2, 3x3 and 4x4 which trades resolution for sensitivity by making the "effective" pixel size larger. This is also useful in tailoring the image scale (arc-sec/pixel) to different optical setups.
Panasonic's new sensor was quickly incorporated into new cameras from ZWO, QHY, Mallincam and others and soon took the CAV community by storm making these the new hot cameras to have. ZWO was the first to incorporate this sensor into its ASI1600 camera which came in both uncooled Color ($699) and Monochrome ($899) versions. The uncooled color camera is now discontinued, but still can be obtained on the used market. They later came out with a cooled Monochrome version ($1280) called the Pro with 2 stage cooling down to -40deg, a 256MB DDR3 memory buffer to help avoid lost frames during high rate data transfers, a USB3.0 port and a USB2.0 Hub to connect accessories such as a filter wheel, guider and a focuser. The camera also has an autoguider port in case you want to use it as a guide camera.
QHY and Mallincam soon followed with similar cameras of their own incorporating this new Panasonic sensor. The QHY163 comes in color ($899) and monochrome ($1199) versions and also includes 128MB of DDR memory, a USB 3.0 interface, guide port, two stage cooling to -40C cooling and a sealed chamber with a heated window to prevent dew from building up. Mallincam's SkyRaider DS16 comes in 3 versions, color ($999), monochrome ($1299), both with a fan for passive cooling and TEC version ($1700 color, $1900 monochrome) with active cooling. They all have a USB 3 interface, a sealed chamber, DDR memory and a full featured software, Mallincamsky, for camera control, capture, live stacking and dark frame subtraction. The TEC version includes a USB Hub and a heated window for dew prevention. Both the ZWO and QHY cameras use the free software Sharpcap which performs all of the same functions as Mallincamsky and much more if you pay for the Pro version, but that is a topic for another blog.
There are still more versions of cameras incorporating the Panasonic 4/3 chip, but I will not list all of them here.
These new cameras appear to have had two major impacts on the way we do real time viewing.
First, if you read the threads on the Cloudy Nights forum, you will see that many amateur astronomers have moved away from the long exposures of 30 sec to minutes common with the security type astronomy cameras like the Mallincam Xtreme and Xterminator or the Revolution Imagers 1 and 2. With such low read-noise it is now practical to use programs like Sharpcap to stack many very short exposures of a few seconds on the fly to get as good or better image after 30sec to minutes but with less demand on the quality of the mount and the polar alignment. In fact, Alt-Az mounts become even more practical for CAV with such short exposures and the use of an on-the-fly stacking program. This can both minimize the cost of the setup and reduce the overall hassle in getting a good polar alignment. Obviously, a better mount and more time spent on a good polar alignment will improve the experience, but less so with exposures of 2 to 5 sec which is now practical with this new sensor.
Second, since the pixels are square not rectangular stars are round unlike their appearance with CCD analog cameras and they do not have the black halo common to stars in images taken with analog cameras. Also, with pixels about 1/3 the size of the pixels in analog cameras much more detail can be seen in galaxies and nebular with the new sensor. Images obtained are of much higher quality than ever before. The net result appears to be a move by many CAV folks more and more in the direction of traditional astrophotography. It has become increasingly the case that dark frame subtraction and even flat frames are both employed with on-the-fly stacking to get the best possible image. The ideal case is to be able to view the image in real time to get the immediate enjoyment of observing deep sky objects, while saving individual frames for later post processing to obtain an astrophotography quality image. In fact this can be done with Sharpcap using the Live Stacking feature while selecting the option to save individual frames in FITs or PNG format for later post processing.
As is always the case, time marches on and even newer products come to market. It appears that the successor to the ASI1600 is the ASI294 with the Sony IMX294 CMOS chip. It too is a 4/3 sensor with extremely low read noise. Even thought it has less pixels at 11.7 Megapixels, the major new advantage of the ASI294 is it's much deeper well which provides a significant advantage for dynamic range. Perhaps a topic for a later blog.
I have been using the ASI1600MC for the last two years and am very happy with it. However, only the mono versions are still available. My astro buddy uses the ASI294MC color cooled version and has had great success with it. You can find the products listed in this blog in the links provided below. As an Amazon Associate I can earn from qualifying purchases through my site with no additional cost to you which helps to defray the cost of this website.
Until recently the only way to view deep sky objects in real time with the assistance of a camera was with one of the many analog cameras like those from Stellacam, Mallincam, Altair Astro, Samsung and a few others. These security cameras re-purposed for astronomy have very sensitive CCDs which can collect enough light in a few seconds to a few tens of seconds to provide stunning views of a wealth of deep sky objects. Some of these cameras have been modified to provide improved astronomical performance. These may include extended exposure, reduced amp glow, sensor cooling, remote control and more, while other cameras like the Samsungs have no astronomy modifications at all. In either case, they provide the user with many important advantages over the traditional view through an eye piece such as:
Since these are analog cameras, they provide a video signal which can be viewed directly on any video monitor, LCD or television with a video (RCA) input. All that is needed is the appropriate cable and connector. Images can also viewed on a computer if the video signal is connected to the computer through a video capture device like the Pinnacle Dazzle or EzCap. Using a computer has the added advantage of allowing the user to capture images, as well as, utilize fancy software programs to stack frames on the fly, remove hot/warm pixels with dark frame subtraction and perform other miraculous feats to greatly improve the detail in the image being viewed live.
Somewhere around 2009, people discovered that the Starlight Xpress Lodestar guide camera was actually a very good camera for viewing deep sky objects in real time. This camera uses the PAL version of the same very sensitive CCD sensor as the Mallincam Xterminator, the Sony ICX829. While the Xterminator is another analog camera, the Lodestar is a digital camera with a USB output which can be connected directly to a computer without a video capture device. And, unlike the analog cameras which need separate cables for power, signal and control, this digital camera uses the single USB cable for all three functions. On the other hand, since the output is digital it cannot be connected directly to an LCD or other analog display device and needs a computer to control the camera and view its output. The Lodestar is controlled with Paul Shears software, Lodestar Live (now called Starlight Live) which also provides the ability to view, capture, stack and stretch images live while watching them improve in depth and detail. Despite these capabilities, most real time viewers seemed happy to continue to embrace their analog cameras including several newer and better cameras like the aforementioned Mallincam Xterminator, the LnTech300 ( also sold as the Revolution Imager 1) and the Revolution Imager 2.
Then, in 2015 a company in China called ZWO introduced an astronomy camera with a CMOS sensor, the Sony IMX224. Their ASI224, like the Lodestar, is a digital camera but with much higher resolution than the Lodestar and all of the analog cameras while maintaining very good sensitivity. The ASI224 is controlled with a software program called Sharpcap, which has all the same features as Starlight Live and more. Even though the ASI224 has a small sensor, 1/3", it has 1.27 Mega pixels, more than double the Lodestar and all astronomical analog cameras. And, its square 3.75 micron pixels are less than half the size of the typical analog camera pixels which provides more detail and more realistic looking stars, i.e. round instead of square. In addition, the read out noise of the ASI224 is so low as to make it much more practical to perform live stacking of many very short exposures (2 to 5 sec) with a program like Sharpcap. This minimizes the demands on mount alignment and makes it more practical to use Alt-Az mounts for real time deep sky viewing. The relatively inexpensive ASI224 (originally $350) fast became a favorite of many who had been using the analog camera and soon other manufacturers like Mallincam, QHY, Rising Tech, Orange County Telescopes, Altair Astro came up with their own versions of cameras with the Sony IMX224 CMOS sensor.
Within just a few months, two other digital astronomy cameras for real time viewing became available. One is the well regarded camera from Atik named the Infinity. This camera uses the Sony ICX825 CCD sensor with 1.4 Mega pixels which are slightly larger at 6.45 microns than the IMX224. This is also a 2/3" sensor which provides a much larger FOV at 11mm diagonal compared to the ASI224 at 6mm. It comes with the highly acclaimed Infinity software with all of the same great features for live viewing as the Lodestar software. In fact, the Infinity was the first ATIK camera marketed as a "video camera". Even with a substantial price tag of $1000, the Infinity became very popular particularly as it is noted for its ease of use, especially for beginners.
Around the same time StarLight Xpress came out with their own camera using the ICX825 sensor called the Ultrastar which uses the Starlight Live software just like the Lodestar. And it was not long till Mallincam came out with their version of an ICX825 camera called the StarVision. While the Infinity, Ultrastar and StarVision use CCD sensors as opposed to a CMOS sensor like the ASI224, they all are digital cameras with a single USB output. With these cameras widely available in late 2015 or early 2016, one could say that the floodgates were suddenly opened to digital cameras for real time astronomy.
Not to be outdone, ZWO came out with another digital camera in the spring of 2016, the ASI1600 camera utilizing the Panasonic 4/3" CMOS sensor with 16 Mega pixels. This was a quantum leap in field of view compared to the 1/3" IMX224. The ASI1600 came in color, B&W, cooled and uncooled versions. Atik followed with their own version of this sensor called the Horizon. Both cameras have extremely low read noise, making them ideal for stacking of very short exposures. It was not long before Mallincam also came out with a camera, the DSC16, which uses the Panasonic 16Mega pixel sensor. Camera manufacturers try to differentiate themselves from the pack using identical sensors by providing unique mechanical form factors, added internal memory, different methods of cooling and different software. More recently, ZWO (ASI294) and Mallincam (DS10c) have come out with digital cameras for camera assisted viewing using the latest Sony 4/3" format IMX294 sensor. The IMX294 is a CMOS sensor with 11.7 Mega pixels and very good light sensitivity.
Judging from the posts on the Cloudy Nights "EAA Observation and Equipment" forum, digital cameras are now the new norm for camera assisted viewing. This is not to say that analog cameras are long gone, but do not expect new models to be introduced as all of the manufacturers appear to have shifted to digital cameras. Analog cameras will still have their place so long as they are available new or used, but it is clear that the digital wave has taken the forefront.
I have been using the ASI1600MC for the last two years and am very happy with it. However, only the mono versions are still available. My astro buddy uses the ASI294MC color cooled version and has had great success with it. You can find the products listed in this blog in the links provided below. As an Amazon Associate I can earn from qualifying purchases through my site with no additional cost to you which helps to defray the cost of this website.