If you're curious about the before/after stuff, have a look at this. This is M15 at 50% of the real size...
Single 20s Dark Frame
Single 20s Dark Frame
stacked, dark frame subtracted
Final image
M13, M5, M81, M82
Tasco StarGuide
80 OTA on NexStar 5i mount
80mm Aperture, 400mm Focal Length, F5 telescope
Equatorially mounted (OK but not great Polar Alignment - was feeling lazy)
Modified Vesta 675 SC Webcam
04/15/2003
This was my second night out with a short tube 80 on the NexStar 5i's mount. The first night was beautiful though the Moon was 2 days from being full. I was planning to use AstroVideo for the first time to give FITS files a go, and my intention was to image only M81 the entire night to get as many images as I could at various exposures. All but a couple dark frames turned out completely 100% black. There was a software/hardware malfunction somewhere along the line. Oh well!
The next night I hedged my bets and used the tried and true K3CCD Tools for a bit and then went back to give AstroVideo another shot. It worked this time, only the sky wasn't as clear and the Moon was 1 day closer to full. I was also not in a perfectionist mood so my polar alignment wasn't perfect and I went for quantity over quality. So, I managed a couple globular clusters as seen here, and a couple of galaxies (M81/M82) but I'm not sure the galaxies will ever be worth the time and bandwidth to even share them. Noise was high in the camera and the sky glow was such that I couldn't expose for very long. And not having a lot to stack means that the S/N ratio is very poor. I will endeavor to change into perfectionist mode the next time I go out and I think I'll leave galaxies for nights when the moon is not so bright.
Processing FITS is different than what I'm used to with K3CCD Tools and/or Registax. I have tried using AIP4WIN and haven't done very well at it. I can create Dark Frames very well with it, but the rest is pretty awful. So, I made my darks using this program and then converted the FITS to BMPS using FITS2BMP and stacked in either Registax or K3 depending on what computer I was sitting at.
I used Photoshop for final processing and believe me, they needed a lot. Someday I'll learn to take better images so that the final processing doesn't have to be so severe. Honest! ;-)
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If you're curious about the before/after stuff, have a look at this. This is M15 at 50% of the real size... Single 20s Dark Frame
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Single 20s Dark Frame
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stacked, dark frame subtracted |
Final image |
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As I'd stated earlier, my intention the previous night was to image M81 solely. I really wanted to see a spiral galaxy with spirals, as opposed to what I see at the eyepiece which is just a fuzzy patch. I guess I didn't go long enough because while I've seen amateur photos using webcams produce spirals in M81, I didn't do it. My polar alignment wasn't all that hot anyway, so even if I went deeper, I'm not sure I could have tracked long enough. The sky glow didn't help in processing these. But, in any case, here's M81 with a short tube 80mm F5 scope and a Vesta 675 SC2
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And here's M82 with a short tube 80mm F5 scope and a Vesta 675 SC2 |
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Not very impressive compared to my NexStar 5i image of it.
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