Quote:
Originally Posted by Ambermile
To tell the truth it didn't make that much difference on the big dob
Arthur
|
I have found that my f/5 mirror causes quite a lot of coma on my 22 Panoptic, and it is bugging me to the point that I really have to do something.
I know a couple of blokes who swear by the TV Paracorr....they say that on an 18" f/4.5 mirror the Paracorr brings out excellent correction, and although you would think that the extra glass cuts down the light transmission, in fact because it brings the stars to a sharp point, a whole lot of extra stars which are just outside the range of visibility when coma-smeared without the Paracorr, become visible with the Paracorr. Suddenly globs have double the number of stars......
I am also led to believe that coma correctors have a more pronounced effect on lower mag EPs. That is to say, you will have far more benefit using one with an EP in the 20-35mm focal length range than below that. Ironically, it is the widefield views, such as open clusters, where you want to have sharp stars to the edge of FOV.