Crescent Moon Image Contrast Study Using DSLR Camera M. Hasan Faadillah (a*), Mahasena Putra (a,b)
a) Astronomy Study Program, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Indonesia
*faadillahmhasan[at]gmail.com
b) Bosscha Observatory, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Indonesia
Abstract
Observation of new moon (young crescent) is almost always related to determination of the beginning months in the Hijri calendar. Observation/sighting of the new moon has gained much interest from various groups using instruments that are easy to obtain and widely available on the market. The use of portable telescope and DSLR camera is one the preferred configuration. Observations of new moon are usually carried out around twilight, where the moon is still relatively young, has a very weak light compared to the background sky (close to the Sun). Theoretical models of the visibility of celestial bodies, including Moon, around twilight had been developed by some authors. These open opportunities to study the contrast of crescent moon image, and put some constraints on models using the increasing amount of data.
In this study, an alternative method for processing crescent moon images, obtained using DSLR camera (in Red, Green, and Blue channel), to estimate the brightness of the Moon and the background sky is presented. These two brightnesses are then used to determine the young crescent contrast, following a specific definition. The contrast values (\(C_{obs}\)) are compared to a theoretical model \(C=C(h_{\odot},\epsilon,h_{Moon})\), where \(h_{\odot}\), \(\epsilon\), and \(h_{Moon}\) are altitude of the Sun, elongation, and altitude of the Moon.
Keywords: Contrast- DSLR camera- Hilal- Image processing- New moon crescent
