TFOV = (Field Stop Diameter / Telescope Focal Length) × 57.3 This uses the physical ring inside the eyepiece that limits the field.
: A professional-grade tool that focuses on matching camera pixel size with telescope focal length to ensure your images aren't oversampled or undersampled. How These Calculators Work astro fov calculator top
Calculating your FOV is essential for ensuring your target fits within your frame. The method differs between visual observing and imaging: 1. Imaging (Sensor-Based) FOV TFOV = (Field Stop Diameter / Telescope Focal Length) × 57