Steven's Basic Astro Calculator

Quick Selectors

Telescope Characteristics
Aperture (mm):
Focal Length (mm):
Max Magnification:
Min Eyepiece Focal Len (mm):
Resolving Power (arcsec) Red: Green: Blue:
(NOTE: According to Chaisson and McMillian atmospherics limit resolving power to 1 arcsec)

Eyepiece Characteristics
Focal Length (mm):
Apparent Field of View (degrees):
Magnificiation (power):
True Field of View (degrees):

Camera Characteristics
Image Plane Width (mm): Height (mm):
Pixels Wide: High:
Tele-Extender Length (mm):
Pixel Size (mm): X Total Size (μm^2) :
FOV without eyepiece (degrees): X
Angular Pixel Size without eyepiece (arcsec): X
FOV with eyepiece (degrees): X
Angular Pixel Size with eyepiece (arcsec): X

Object Information
Apparent Brightness (magnitude):
Angular Size (arcseconds):
Apparent Size in Eyepiece (degrees):
Note: The below calculations assume a roughly square object
Theoretical Best Image Size (total pixels) red: blue:
Image Size (total pixels) without eyepiece: with eyepiece:
Illumiance (lux):
Luminance (lumens):
Luminance per pixel (lumens) without eyepiece: with eyepiece: