Astrosat: forecasting satellite transits for optical astronomical observations

James Osborn*, Laurence Blacketer, Matthew J Townson, Ollie J D Farley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)
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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 40 000 satellites in the constellation that number would increase to 30.
Original languageEnglish
Pages (from-to)1848-1853
Number of pages6
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Early online date20 Oct 2021
Publication statusPublished - 17 Nov 2021
Externally publishedYes

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