Quote:
Originally Posted by Moonboy
Could you (or anybody who knows) please tell me the formula or equations to calculate this, as I do not know how to do it  . |
1. The moon visual diameter is approximately 31 arc minutes but varies quite a bit depending on where it is in its orbit. This is probably nice to know for comparative purposes but needs other information for any accuaracy.
When the size is given in degrees and fractions multiply the decimal fraction by 60 to get minutes and the "rest" by 60 to get seconds eg.
FOV = .477 degrees 12" LX200 with 26mm eyepiece no field stops
x60 =28.62 minutes
rest .62
x60 =37.2 seconds
If it is given in Radians
multiply radians by 57.29577951 to get degrees.
In regard to field stops. Yes this is a factor that can be taken into account but will also need other information from the field stop. A calculator in most instances would need to default to "1" as a multiplying factor if this information is not published or otherwise available.
Barry
PS kowing the size of objects and your approximate FOV will show that most of the best DSO's do not need a magnification of better than 30x for the best views.