Sagitta to Focal Length Calculator

Did you buy a partially ground mirror at a swap meet and want to know it's focal length? Or perhaps you have been grinding your own piece of glass and want to know the current focal length. Just input the Sagitta (depth of curve) and Mirror Diameter, and this page will calculate the Focal Length, Focal Ratio and Radius of Curvature.

If you want to calculate many other telescope and mirror parameters, use our Telescope Formulas and Design Comparator page.

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Parameter	Value	Units
Sagitta (s):
Mirror Diameter (D):

Output Written Here

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