Magnification Calculator

Telescope Specifications
Eyepiece Specifications
Aperture Diameter (inches) user input Eyepiece focal length 
user input
Focal Ratio 
user input Magnification
Focal Length (inches) Eyepiece Apparent FOV 
user input
Focal Length 
True Field of View 
(sq. inches)
True Field of View
Barlow (x) user input Directions:
  • Enter values for the "user input" blocks - then press the "Calculate" key
  • Eyepiece Apparent FOV Table - A listing of popular manufacturers eyepieces and their apparent field of view's (FOV).
Telescope Characteristics
Resolving Power 
Limiting Magnitude (ML) Table

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Version 4.1 by Matt Oltersdorf 2000 04 10 10:00 UTC