Name: Terry H.
How do you compute the theoretical resolving limit (in arc seconds) and the
faintest stellar magnitude visible for any given aperture, focal length and magnification?
(I am using a 6 inch Newtonian reflector with 1400 mm focal length and a 28mm Plossl
What you are referring to is Dawe's limit, which is determined by the following simple
R' = K / A
where R' is the maximum theoretical resolution in arc seconds
K is the empirically determined constant 4.56
A is the clear aperture (unobstructed effective diameter of the object lens or mirror)
You may wish to consult the following source:
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Update: June 2012