Astromath Calculator

Click here for a printable form
to use with this calculator.

Focal Ratio

Objective Focal Length	Objective Diameter	Focal Ratio

Magnification

Objective Focal Length	Eyepiece Focal Length	Barlow (1=none)	Magnification

Actual Field of View

Apparent Field of View	Magnification	Actual Field of View
degrees		degrees

Apparent Field of View

Actual Field of View	Magnification	Apparent Field of View
degrees		degrees

Exit Pupil

Eyepiece Focal Length	Focal Ratio	Exit Pupil

Longest Practical
Eyepiece Focal Length

Focal Ratio	Exit Pupil	Eyepiece Focal Length