BVRI Photometry of Space Debris Objects at the Astronomical and Geophysical Observatory in Modra

摘要

In Fall 2016 there has been deployed a new 0.7-meter aperture Newtonian telescope (AG070) at the Astronomical and geophysical observatory in Modra (AGO). This system belongs and is operated by the Faculty of Mathematics, Physics and Informatics of Comenius University in Bratislava, Slovakia (FMPI). The major research focus of AG070 is dedicated to the observations of space debris which are objects such as defunct satellites, rocket bodies and fragmentation pieces. AG070 is equipped with commonly used BVRI Johnson-Cousins filters, which provide an opportunity to perform color photometry. The main motivation of research in field of color photometry is to obtain data for characterization of objects depending on their surface properties and their changes over time. Data acquired from this telescope was processed with the photometric reduction routine, which was developed by our team. We used Landolt's catalogue of standard stars, to obtain necessary coefficients for transformation to standard system of magnitudes, as a zero-point of telescope, an extinction coefficient and a color transformation coefficient. Using the least-squares method we estimated values of the coefficients for each selected photometric night and used them to transform object's intensity from instrumental to standard system of magnitudes.