It has been nearly 20 years since SBIG in Santa Barbara introduced the STV for the tidy sum of $1995. This video camera was marketed as both a deep sky video camera and a stand alone guider. At its heart is a Texas Instruments TC-237 1/3" format B&W CCD sensor with 656 x 480, 7.4micron square pixels. In retrospect, for its time, the STV was revolutionary. From my research it the first video camera to be capable of deep sky video without modification, years before the Stellacam, Mallincam, Samsung, Mintron or Watec cameras. Not only that, it came with an amazing list of features which we now take for granted in our CMOS based video cameras but which did not become widely available until the past few years. This includes, exposures up to 60 minutes, manual gain (1x or 2x), thermo-electric cooling, 1x1, 2x2 and 3x3 internal binning, internal stacking and alignment of successive frames called "Track & Accumulate" and an optional 5.3" LCD monitor. In addition, it had an internal filter wheel with a green filter to act as a "neutral" density filter when viewing the moon, and an opaque filter to support internal automatic dark frame subtraction. An optional color filter wheel was also available for color imaging. The unit came with 2MB of internal memory to save up to 14 images which could be downloaded to a computer later.
The camera came with a rather large control module with buttons and knobs to scroll through the camera menu and adjust camera settings. The settings were viewed on a small, two line LCD display. An optional 5" LCD monitor showed the live images. Accessories included a very thorough manual, a 110VAC to 12VDC transformer, RS232 cable to connect the control module to a computer, RJ11 auto-guide cable, red screen shield for the LCD monitor, 1.25" nose piece adapter, software for remote operation of the camera via a computer, and copies of CCDSoft and CCDSharp. Additional options included an eFinder tube assembly with a focal reducer to turn the camera into a stand alone guider, the previously mentioned color filter wheel, adapters for 35mm cameras and a hard carrying case with custom cut foam.
I have seen some surprisingly good images of galaxies and nebulae taken with this camera and posted on the internet. So, as a student of deep sky video history, I recently purchased one of these cameras on Cloudy Nights to see what it could do for myself. First of all, everything is big from the camera, to the control box to the power supply. I guess this is not a surprise given the state of the art of electronics 20 years ago. Second, a short read of the quick start guide in the manual enabled me to begin taking images in quickly. The controls are quite easy and mostly intuitive. When in the imaging mode, the two round knobs on the front panel are used to adjust the brightness and contrast of the image as viewed on the LCD. To capture images with this camera, I used the video out port on the control module and fed the signal through a video capture device to my computer which was running Sharpcap software. I used Sharpcap to view and capture the images shown below.
So far I have only tried the camera with an ES 127mm, f/7.5 Apo refractor, but have been pleasantly surprised with the results. I have used the camera both with and without a generic 0.5X focal reducer and without any filters. I will note, the images as they appear on the SBIG LCD monitor are noticeably better than the images on my computer screen. I use the same video cable and Pinnacle Dazzle 100 to send the signal to my computer as I do with all my other analog video cameras, so I am guessing the difference is due to the output on the SBIG control module.
Since it is the Christmas season, Orion is an obvious target. Below is a single frame, 10sec image of M42 taken with a gain of 1X. While the core is blown out, we can see significant detail in the nebulosity. Next is a 30sec single frame image of the Flame Nebula. The 5.6mag variable star NSV16638, which is just on the edge of the top of the image makes it difficult to avoid washing out the nebula but I was still able to see it clearly. The HorseHead nebula is difficult to see in a light polluted back yard, especially without filters, but this 60sec image shows it quite well.
One of my favorite galaxies this time of the year is M82, the Cigar Galaxy. The STV had not trouble bringing out the split in this galaxy even at a few tens of seconds. The image shown here used the Track & Accumulate feature, aligning and adding 5 x 30sec frames for a total of 150sec. Notice how nice and round the stars are and compare this to the elongated stars in the 60sec single frame of the HH Nebula. I would say that the T&A feature works quite well, and this was available almost 20 years ago. Next are two 60sec single frame images of M82, the first without the internal dark frame subtraction and the second with dark frame subtraction. Notice the dramatic difference. And, I did not even have to get up and cover and uncover the scope to do this. It was all automatic one I check yes in the camera menu for dark frame subtraction. Since this CCD sensor is nearly 20 years old, I have no way of knowing if this is typical of the number of hot/warm pixels when the sensor was new. Nevertheless, dark frame subtraction is able to take care of the objectionable noise.
All in all, I am very impressed with what this camera can do. When I realize that this camera had all of the extra features in 1999 that most cameras/software did not have until recently I am even more impressed by SBIG. If not for the much older vintage (1996) and smaller format (1/3") CCD (TC-237), this system would still be a competitive analog video performer today. Not to mention, that many people still use this as a stand alone auto guider for their long exposure imaging. No wonder I had a tough time getting someone to part with this.
Next time I have clear dark skies, I will see if I can improve the images, especially the star bloat with filters. And, I would like to try the camera out on my 9.25" SCT which will pull in more light than the 127mm refractor.