Hi Rob, Can you get rid of some of the coma by closing the lens down a bit (ie. larger f/number)? Patrick Rob Ratkowski wrote:
Aloha Chuck
The Zenitar is an OK lens to play with and you are right, the big $$ Fisheye lenses are better but not by much when it comes to low light-astrophotography. Where the better lenses excel is in edge sharpness. I just posted an image from my experimental 4X5 AllSkyCam http://www.utahastronomy.com/rob/eAllSkyCam_8_12_05 and it is made with an inexpensive Russian made lens for the 6X6 Pentacon cameras and exhibits coma flaring along the edge of the image circle. The lens has a sweet spot in the center but along the edges, no comment. I'm still having fun capturing a big chunk of the sky ..................
Aloha from WINDY Maui Rob