I have the Lumicon coma corrector, bought it used about ten years ago for a song. It is optimized for f/4.5, but shows moderate improvement with f/4 to f/5 systems. I never need it on anything I own slower than f/5. Just about any fast mirror has some coma. It is made more apparent using wide-field eyepieces, sometimes disappears completely with more mainstream eyepiece designs such as Plossls & Orthos. If you use TV eyepieces, I would suggest the TV coma corrector, otherwise use a more "mundane" eyepiece line, with a field that lies inside the coma-free zone (or at least shuns the outer, most offensive areas). My comments are for visual use. I"ve never used the Lumicon unit for imaging, so I can't comment on whether the field is truly flat. Too, coma is usually only apparent at very low powers. Don't think of it as mirror "flaw", think of it as a mismatch between the mirror and your eyepieces. --- DunnDave@aol.com wrote:
Does anyone have any expirience with Coma Correctors? My newly completed 16" f/5 has coma. I would appreciate any advise anyone might have on how to deal with coma. The Lumicon and TelVue correctors are several hundred dollars so I don't want to just buy one to experiment.
Thanks. Dave
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