Three Ways To Calculate Magnification

Known Focal Lengths

Telescope:

Units:

Inches Millimeters

Eyepiece:

Focal length of eyepiece in millimeters

      Fill in focal lengths of telescope and eyepiece.

Known Diameters

Objective:

Units:

Inches Millimeters

Exit Pupil:

Diameter of exit pupil in millimeters

      Fill in diameters of objective and exit pupil.

      (You may use either nominal size or clear aperture for objective.)

Known Field Angles

Apparent Field:

Use same units for both angles.

True Field:

Units:

degrees Arc Seconds

       Fill in angles for apparent field and true field.

       (Express fractional parts as decimals.)

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