Here are the best online and app-based calculators to use for your astronomy planning. 1. Astronomy Tools FOV Calculator
An interactive calculator uses this fundamental formula to tell you how many degrees of sky you can see: Sensor Dimension Focal Length
FOV (degrees)=(Sensor Dimension (mm)Focal Length (mm))×57.3cap F cap O cap V (degrees) equals open paren the fraction with numerator Sensor Dimension (mm) and denominator Focal Length (mm) end-fraction close paren cross 57.3 : The width or height of the camera sensor.
Quick visual framing checks and matching cameras to telescopes. astro fov calculator top
There are several types of Astro FOV Calculators available, catering to different needs and preferences:
This Android app excels at calculating a wide range of parameters for telescopes using different eyepieces, with a focus on visualization. It covers key metrics like field of view, maximum field of view, exit pupil diameter, angular resolution, and even the size of craters on the Moon. It's perfect for understanding the full implications of your equipment choices.
Features an extensive, user-updated database of telescopes, eyepieces, and cameras. It allows you to drag around a "Target" (like M42 or M51) and overlay your chosen equipment setup to see exactly how it will be framed. Here are the best online and app-based calculators
TFOV measures the actual patch of sky captured by your sensor, expressed in degrees, arcminutes, or arcseconds. Pixel Scale
Planning, simulation, and real-time viewing on a laptop or smartphone. 3. Telescopius Astronomy Tools
Mastering the Night Sky: Top Astro FOV Calculators for Astronomers in 2026 Quick visual framing checks and matching cameras to
An astro FOV calculator simulates this relationship visually or numerically. Using one allows you to:
This web-based tool, often powered by the 12dstring database, is another robust option for selecting telescopes, eyepieces, and cameras to visualize your view, as noted in the BBC Sky at Night Magazine.