Telescope Aperture/Resolution Calculator

Resolution and limiting magnitude from aperture

Aperture (mm)

Formula

Dawes limit = 116/D arcsec | Limiting mag = 2.7 + 5 log10(D)

What is the Dawes limit?

The Dawes limit is the minimum angular separation two stars can have and still be resolved. It equals 116/D arcseconds.

What is limiting magnitude?

The faintest star visible through a telescope. Larger apertures see fainter objects.

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