Andrew Welsh 
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1_of_9 wrote:
Andrew, another wonderful image. I have had an interest in astrophotography since boyhood...back then we used film and tried cooling schemes. I'm interested in what scope you use?..do you use it's native focal length or do you use eye pieces? Last time I read about this seemed many were using web cams to stack images...and I wondered why they didn't just use a digital camera....that you use a Rebel - I imagine - these are quite detailed in their full resolution. Love the variety of color in the stars..adds real depth.
Thanks 1 of 9. Check my profile for my equipment list. This is at the native focal length of the scope, using a t-ring adapter to connect the camera to the back of the scope.
Webcams far outperform DSLR's for astrophotography when photographing very bright objects, which includes: the moon, the sun (properly filtered), mercury, venus, mars, jupiter, saturn, the ISS, Hubble Space Telescope. Uranus and Neptune are dim enough and lack enough detail to the point where a webcam has little advantage over a DSLR. Photographing anything else in the sky, the DSLR wins hands down over the webcam.
The reason is because looking at the night sky is like looking into a swimming pool. The atmosphere distorts and smears the image. If you've seen down a long road on a hot summer day the shimmering mirage, the same effect occurs all the time.. except the telescope enlarges the effect up to 100-300 times. Over 5 hours of exposure it all kind of averages out which is what you see above, but for bright objects like planets, you can catch that still 1/10th of a second where the atmosphere is clear by recording a video with a webcam. And despite the crappy resolution of a webcam, you have the power of numbers on your side. Recording a stream of hundreds of frames in a few minutes, you can then stack the still frames and sharpen the bejeebers out of it to get all of those lovely details.
The "pro" planetary photographers (Google Damian Peach or Chris Go) use astro-dedicated video CCD cameras, which can record high frame rates (30 or 60fps) without any or very little data compression, which allows them to get even more still moments and high-resolution frames. Chris Go started with a webcam himself and ended up getting time on the Hubble, and invited up to the Keck telescope on Mauna Kea in Hawaii (the world's largest), due to his planetary webcamming.
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Should be "Patterns in Space" 
