English

Astrosat: Forecasting satellite transits for optical astronomical observations

Instrumentation and Methods for Astrophysics 2021-11-23 v1

Abstract

The impact of large-scale constellations of satellites, is a concern for ground-based astronomers. In recent years there has been a significant increase in the number of satellites in Low-Earth Orbit and this trend is set to continue. The large number of satellites increases the probability that one will enter the field of view of a ground-based telescope at the right solar angle to appear bright enough that it can corrupt delicate measurements. We present a new tool Astrosat that will project satellite orbits onto the RA/DEC coordinate system for a given observer location and time and field of view. This enables observers to mitigate the effects of satellite trails through their images by either avoiding the intersection, post-processing using the information as a prior or shuttering the observation for the duration of the transit. We also provide some analysis on the apparent brightness of the largest of the constellations, Starlink, as seen by a typical observatory and as seen with the naked eye. We show that a naked eye observer can typically expect to see a maximum of 5 Starlink satellites at astronomical twilight, when the sky is dark. With the intended 40000 satellites in the constellation, that number would increase to 30.

Keywords

Cite

@article{arxiv.2111.11268,
  title  = {Astrosat: Forecasting satellite transits for optical astronomical observations},
  author = {James Osborn and Laurence Blacketer and Matthew J. Townson and Ollie J. D. Farley},
  journal= {arXiv preprint arXiv:2111.11268},
  year   = {2021}
}
R2 v1 2026-06-24T07:47:28.589Z