Diamap calculates the apparent diameter of an object according to the focal distance of the telescope and the eyepiece you are using. It plots/compares the apparent diameter against the actual FOV of the eyepiece.
Focale is a generic telescope optical parameters calculator with, perhaps, something new: and indication of the focal lenght (mm) of the eyepiece you must use to achieve minimum, maximum and optimal amplifications with a given telescope.
The screen shots are pretty self explanatory (click the thumbnail at your right).
