Analytic vs. Montecarlo simulations of satellite visibility

Abstract The predicted impact of large satellite constellations on optical astronomy has been worked out, from the beginning, using Montecarlo methods: individual satellite orbits inside each shell are randomly initialised and satellite tracks are computed one by one to check whether or not they hit the field of view, and under what conditions. However, it is known that the density of satellites inside each shell follows the analytic double-sine probability density distribution, which offers new ways to get similar results at a much lower computational cost. We compare results obtained applying the two approaches and we derive some conclusions on the advantages and drawbacks of each method. The original FORTRAN code of the software is available at https://galadi.net/satsim/ .