What can your sensor see?

Enter your telescope, camera, and optional target size to find out how much sky fits in your frame.

Inputs
1 = none, <1 = reducer, >1 = Barlow
Leave blank to skip target fit check
Results

Adjust the inputs to see results.

Small-angle approximation (Huygens formula): FOV = 57.296 × sensor size / focal length

All formulas verified by automated tests.