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This paper outlines a multi-system approach for ground-based optical observations and the characterization of satellites in geostationary orbit. This multi-system approach is based on an in-depth analysis of the key factors to consider for light curve analysis of Earth's orbiting satellites. Light curves have been observed in different spectral bands using two different systems. The first system is specialized for astronomical observations and consists of a telescope equipped with an sCMOS camera and Sloan photometric filters. In contrast, the second system is a more cost-effective solution designed for professional non-astronomical applications, incorporating DSLR cameras equipped with RGB channels associated with a Bayer mask and photographic lenses. This comparative analysis aims to highlight the differences and advantages provided by each system, stressing their respective performance characteristics. The observed light curves will be presented as a function of the phase angle, which depends on the relative positions of the observer, the object, and the Sun. This angle plays an important role in optimizing the visibility of Earth's orbiting satellites. Finally, multiband observations of different satellites will be compared to seek an associated spectral signature, which may allow the identification of structurally similar objects through optical observations. [ABSTRACT FROM AUTHOR]

The number of satellites orbiting the Earth has significantly increased and large constellations based on thousands of satellites are currently being designed and operated. Among them the Starlink project, owned by SpaceX, is in advanced phase. The massive presence of orbiting objects could have a negative impact on astronomical research. In the case of observations with long exposure times and/or wide field of view (FoV), numerous bright tracklets, caused by the reflection of sunlight on a transiting satellite, may appear in the images. For this reason, the Sapienza Space Systems and Space Surveillance Laboratory (S5Lab), which has been involved in research on space debris and space surveillance for many years, started a new research project on the photometric characterization of some satellites of the Starlink project, using red, green and blue filters and comparing the results with observations performed without filters in order to analyze the features of the transit of Starlink satellites. The observations will stress the high complexity of the Starlink satellites reflection pattern, producing interesting results concerned with the used filters and the observation geometry. [ABSTRACT FROM AUTHOR]