JAT Observatory Sky Darkness Data Page

MPSAS = Magnitude Per Square Arc Second. 
NELM = Naked Eye Limiting Magnitude. 
The larger the number the darker the sky.
Updated 8:00pm to 5:00am 
Click image for more resolution
The data displayed is only updated when the Sun is below the local horizon @ 40.16 north - 74.84 West

More info about the SQM-LE

< Special thanks to Greg Kettell for whipping up the PHP code that takes the
raw tabular data file from the SQM Reader(s) and displays  it in a more readable format.

Limiting Magnitude Calculator

This page will auto refresh every 2 minutes.

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Updated 05/18/2013 - Please report broken links webmaster@jatobservatory.org