Telescope Calculator

Use this calculator to calculate a few of the more important aspects of your telescope. Fill in the blue/green form and click 'Calculate'. The results will appear in the yellow/orange form. The minimum required information is the aperture.

NEW! There is now a section where you can specify the size and resolution of a CCD imager or DSLR when used in prime focus (with or without barlow lens).

Aperture:		mm or	inch
Focal Ratio or Length:	f/	or	mm
Eyepiece:		mm
Apparent Field:		degrees
Barlow Lens:		X
CCD sensor size:		mm (W) by	mm (H)
CCD Resolution:		pixels (W) by	pixels (H)

Magnification Range:		X to	X
Light Grasp:		X
Resolving Power:		arc sec
Limiting Visual Magnitude:
Visual Magnification:		X
True Visual Field:		arc min
Exit Pupil:		mm
CCD Field:		arc min (W) by	arc min (H)
Pixel Resolution:		arc sec/pixel

The above calculations are theoretical limits under perfect conditions. Of course the resolving power of the scope will only be as good as the seeing permits.

The optimal telescope/CCD combination is where the Resolving Power is same or slightly less than the Pixel Resolution.