New Jersey Astronomical Association
The Paul Robinson Observatory
Buzz Aldrin Astronomical Center
Observatory Road - Voorhees State Park
P.O. Box 214
High Bridge, New Jersey 08829-0214

SQM Numeric Readings

The data for these charts is collected in realtime using the Unihedron Sky Quality Meter - LE (SQM-LE). The instrument is mounted atop our observatory building in Unihedron's all weather housing.

The realtime collection, management and display of the SQM's raw data is accomplished by using
SQM Reader Pro from Knightware. This software is running on a PC platform and is sending the three charts shown below to our website for immediate display.

We thank Knightware and Unihedron for the very generous donation of the instrumentation and software.

The principal indicator for the quality of our night sky is the "NELM" Value. This stands for "Naked Eye Limiting Magnitude". NELM is the faintest apparent magnitude of a celestial body that is detectable by the Human Eye. NELM is used as an index in the Bortle Scale which Classify's (1-9) the night sky's brightness at a given location.

Our typical reading on new moon evenings with no cloud cover is 5.9 NELM and nights with exceptional seeing we reach 6.2 NELM.

This places us at the top of Class 5 and on the bottom of Class 4 on the Bortle Scale.

Class 5 - Suburban Sky on a typical night.
Class 4 - Rural/Suburban Transition on better nights of seeing.