Analysis of Seven Years of Globe at Night Data

Volume 42 number 1 (2014)

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Jennifer J. Birriel

Department of Mathematics, Computer Science and Physics, Morehead State University, Morehead KY 40351

Constance E. Walker

National Optical Astronomical Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719

Cory R. Thornsberry

Department of Mathematics, Computer Science, and Physics, Morehead State University, Morehead KY (current Address, Department of Physics and Astronomy, University of Tennessee, Knoxville TN 37996

Abstract

The Globe at Night (GaN) project website contains seven years of night-sky brightness data contributed by citizen scientists. We perform a statistical analysis of naked-eye limiting magnitudes (NELMs) and find that over the period from 2006 to 2012 global averages of NELMs have remained essentially constant. Observations in which participants reported both NELM and Unihedron Sky Quality Meter (SQM) measurements are compared to a theoretical expression relating night sky surface brightness and NELM: the overall agreement between observed and predicted NELM values based on the reported SQM measurements supports the reliability of GaN data.