🔭 Telescope Field of View Calculator
Calculate the true field of view for any telescope and eyepiece combination. Essential for planning observations and understanding what you'll see through your telescope.
⚠️BETA: Calculations may contain errors - verify with manufacturer specifications
Camera Settings (Optional)
Reference Object Sizes
Moon:30′ (0.5°)
M31 (Andromeda):190′ × 60′
M42 (Orion):85′ × 60′
Jupiter:~40″
What is Field of View?
Field of View (FOV) is the diameter of the circular area you can see through your telescope. It's typically measured in degrees, arcminutes, or arcseconds.
- • True FOV: The actual area of sky visible
- • Apparent FOV: How wide the view appears to your eye
- • Magnification: How much larger objects appear
How to Use This Calculator
- 1. Enter your telescope's focal length (usually 400-3000mm)
- 2. Enter your eyepiece focal length (typically 6-40mm)
- 3. Enter the eyepiece's apparent field of view (usually 40-100°)
- 4. Click calculate to get your true field of view
💡 Field of View Tips
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Moon Comparison
The Moon is about 0.5° wide. Use it to visualize your telescope's field of view.
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Target Planning
Larger FOV helps find objects, smaller FOV shows more detail on planets.
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Eyepiece Selection
Different eyepieces give different views. Calculate FOV for all your eyepieces.