Limiting Threshold Magnitude Calculator

ASTROMETRICS: Limiting Threshold Magnitude Calculator

(Calculator uses JavaScript1.2 extensively. Problems may occur with some browsers.)

Calculation Input:

Telescope Type:	Refractor
	Newtonian
	Catadioptic
Primary Aperture (mm):
Central Obstruction Size (mm):
Scope Magnification:
Unaided Visual Magnitude Limit:
Atmospheric Stability:

Calculation Results:

Conditional Limiting Magnitude:
Distance to Average Star at Threshold Magnitude (LY):
Total Number Stars Visible throughout Sky:
Average Number Stars in 60 degree eyepiece apparent FOV (excludes Milky Way):
Dimmest Average Open Cluster Visible:
Dimmest Average Globular Cluster Visible:
Dimmest Average Planetary Nebula Visible:
Dimmest Average Bright Nebula Visible:
Dimmest Average Elliptical Galaxy Visible:
Dimmest Average Spiral Galaxy Visible:

To determine whether your scope can find and view a specific DSO
use the Apparent Brightness Calculator.