Two Ways To Calculate Apparent Field Diameter

Known True Field Angle
and Magnification

True Field:

Decimals are ok.  Don't use minutes and seconds.

Magnification:

Telescope Power

      Fill in integers and/or decimals.  No minutes, seconds, nor the letter "X".

Known Image Diameter and
Focal Length of Eyepiece

Image Diameter:

Units:

Inches Millimeters

Focal Length:

Focal length of eyepiece in millimeters only

      Fill in diameter of image and focal length of eyepiece.


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Maintained by Ray Shapp
 Page last updated 06/23/2001