UBC Undergraduate Research

Use of a DSLR camera and integrating sphere to determine the luminance of the Moon Yeraliyev, Anuar; Fan, Kevin

Abstract

A Nikon D80 DLSR CCD camera is used to measure the luminance of the Moon arriving at the Earth's surface. The camera is calibrated using an Integrating Sphere, a Tenma 7250 illuminance metre, and incandescent light bulbs of 60W and 40W. The weighted average camera calibration constant Kc is determined to be 3.56±0.03. Photos of the moon are taken over the period of March 9-18, 2014, then analyzed using aperture photometry in Maxim DL to obtain average absolute pixel brightness of the lunar disk. Upon correcting for the effects of attenuation by atmospheric extinction, increasing lunar phase is correlated with decreasing luminance, with luminance ranging from (1.2±0.1)x10³cd/m² to (5.3±0.7)x10³cd/m² over phase angles of 16.86°≤Φ≤71.24°. The variability of measured luminances is attributed to non-linearity of light detection response with respect to changing camera settings in JPEG format, imperfect diffuse light reflection within the Integrating Sphere, and variability in atmospheric conditions.

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Attribution-NonCommercial-NoDerivs 2.5 Canada