Anyone compare Limiting Magnitude with NV vs Conventional Eyepieces?NV
Posted 05 October 2016 - 02:20 PM
Posted 05 October 2016 - 10:26 PM
Actually, the grinding part is child's play. It's the figuring after polishing out where the optician earns his pay. But a system dedicated to *prime focus* work need not be finished to the degree of spherical correction required for small exit pupil visual work. As long as the departure from nominal on the surface has no locally strong slope, i.e., has a more gradual deformation with no pronounced zones, the p-v wavefront error could approach a full wave. The most important region to keep under better control is the outermost edge, because even a fairly narrow annulus here occupies a surprising fraction of the working area.
Posted 05 October 2016 - 11:17 PM
The Pronto was the obvious winner, showing much higher brightness on M31. At first look it appeared that the star fields were identical. However, without much trouble, I was able to locate a nearby star that was barely (but clearly) visible in the Pronto that could not be seen at all in the dob.
This would be a good post for Refractors Forum. Or Reflectors. Or Eyepieces.
Posted 07 October 2016 - 09:12 PM
Since this thread never got off the ground with star magnitude tests,
maybe all psyched out from thought experiments,
I decided to try it with the Sony a7s and a target easy to determine star magnitudes....
FWIW, A link for any future readers: