Calculate the true field of view (TFoV) of your telescope and eyepiece combination.
Telescope & Eyepiece Details
mm
mm
°
Calculation Results
Enter telescope and eyepiece specs
About this calculator
Quick Reference
TFoVTrue Field of View
AFoVApparent Field of View
MagnificationTelescope FL / Eyepiece FL
1°60 arcminutes
Overview
This calculator determines the True Field of View (TFoV), which is the actual patch of sky you see when looking through the eyepiece. It depends on the telescope's focal length and the eyepiece's characteristics.
💡
Pro Tips
Standard Eyepieces (Plössl) usually have an AFoV of about 50°.
Wide-angle eyepieces can have AFoV from 68° to 100° or more.
The moon has an angular diameter of about 0.5°, which is a good reference for FOV.
!
Fun Facts
"The Andromeda Galaxy spans about 3°, which is 6 times the width of the full moon."
"Most amateur telescopes provide a TFoV between 0.5° and 2°."
"A larger TFoV makes it easier to find objects in the night sky."
