Re: [APML] OT: CCD ST10 Horsehead

[Chris1011@aol.com]

In a message dated 9/28/2001 8:27:39 AM Pacific Daylight Time, trekkie@spamcop.net writes:


> So what, he needed, oh, $20K worth of equipment to do it? What's the
> problem?  ;)


Actually, you can do similar work with much less equipment. You will need a good mount, but you need that for film photography too. There are CCD cameras available from Starlight Instruments, such as the HX516, that will do superb work and cost only around $1400. A cheap laptop is all you need to control them. The HX516 has 7.4 micron pixels, and will give you very nice images on your monitor, every bit as good as you see in that Horse-Head image. The key to making CCD images work is good technique, same as what makes film images look good. You can give me a $20,000 CCD camera and the best optics, and I can produce crap for you if I don't use good skills. Alternately, I can make excellent images with fairly low end equipment (except for the mounting) with the proper skills. I can get perfect color images with no blue haloes using ordinary achromat lenses. Yes, Apos make life easier, but are not required in CCD work. In film work, they are indispensible. I can shoot phenome!
nal images of vast nebulea with the full Moon high in the sky. Again, film can't do that. 

Nevertheless, there is a place for film. For instance, last night we shot M110 with Mark Jenkin's 9" F4.3 FastMax. We talked about the best way to image the entire M31-32-110 region with the ST10E in color, and came to the conclusion that it would take a good half a year to do it right, even with this wide field instrument. For each L, R, G, B shot we need 15 images of 2 minutes each, and about 10 sets of these for a full mosaic of the region. One 2 minute image takes about 5 minutes with the ST10E, plus we need dark frames, bias frames, flat field frames etc. Time really flies when you are doing CCD imaging. Adding up all the time, and you have about 100 hours invested -before processing- for a top notch color mosaic spanning a 3 to 4 degree region of sky. Now add processing, I figure that I spend 3 hours processing for every hour imaging. So, until they come out with 2" color CCD chips, it just is not practical yet. 

Now consider the film alternative. Nearby was Trent Lott's 7" F7 Apo refractor. With his 6x7 format camera, he could capture the entire region at once. Perhaps 3 or 4 images taken in one night, combined in Photoshop, would create a stunning picture. Perhaps we could combine efforts - film plus CCD. If we took only Luminance images with the 9" Fastmax and ST10E camera, we could mosaic the entire region in perhaps 4 or 5 nights. Then we could combine these high res shots with the color images and have the best of both worlds. 

By the way, the ST10E recorded M110 in considerable detail in 20 seconds. On the image you could see the tiny globulars surrounding the galaxy, as well as several dark lanes. Also shown is a very small faint spiral galaxy just slightly north-east of M110. My version of The Sky does not show anything there, but this galaxy is also just barely shown in one of Tony Hallas' original B&W shots that I have on my wall, taken with a 6" Apo. 

Roland Christen