Quote:
Originally Posted by pkinchington
I am a biological photographer and take photographs of a wide range of subjects both on land and underwater and through the microscope. I have plenty of lenses and my intention was to use my 300mm f/2.8 ED lens on a HEQ5 go to mount with a "feed back camera" to correct the position of the mount if any drift occurs. I have attached my first shot of the orion nebula using the 300mm f/2.8 lens on a full frame unmodified digital camera. I used a regular tripod and took about 3000 photos (1s @ 1600iso) for stacking (some dark and flat frames also). I recentered the orion nebula when it was about to move out of the frame. I was actually tossing up getting a modified dslr (to get the H-alpha band 656nm) or an apo telescope or if I find that I want to do some serious work then buying a monochrome camera with a filter wheel so that I can do narrow band work - I particularly like the results when the hubble colour palette is used. The reason that I was thinking about an apo telescope was that some stars looked mushy in my orion nebula shot and some had what appeared to be chromatic aberration.The William optics GT81 triplet apo scope sounds interesting and how much would a field flattener for this cost? I post processed the stacked image in photoshop where I stretched the histogram through several iterations. I would like to know the community's thoughts on the direction I should take. 
Cheers Peter Kinchington - peterkinchington.com
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Peter,
If this is your first attempt, then not a bad effort but there are a few things to be aware of :-
- Focus is much more critical for astrophotography than just about any other form of photography and your camera is not designed to focus in near darkness
- Most lenses are not optimal when wide open, try reducing the f stop
- There appears to be a difference in focus across the frame
- If you are pointing high in the sky then gravity may cause the focuser to shift
- 1 second exposures are really too short
- A 300mm focal length is starting to become very challenging, try shorter focal lengths until you have developed the required skills
Paul