BHTOM and the European Astronomical Society of Small Telescopes (EASST): Bridging Professional and Amateur Astronomers in Microlensing Studies

The Black Hole Target and Observation Manager (BHTOM.SPACE) is a powerful yet accessible web-based platform that enables both amateur and professional astronomers to contribute to cutting-edge astrophysical research. Developed within the European Astronomical Society of Small Telescopes (EASST.EU), BHTOM supports long-term and rapid photometric monitoring of a wide range of celestial targets, including microlensing events, variable stars, transients, quasars, exoplanets, and moving objects. With contributions from nearly 130 telescopes worldwide, many operated by amateur observers, BHTOM facilitates coordinated observations, automated data processing, and collaboration across the global astronomical community. The platform is designed to make it easy for small-telescope users to produce science-ready data and participate meaningfully in ongoing research campaigns. One of the key science focus of BHTOM is gravitational microlensing, a technique that can reveal invisible objects such as black holes, neutron stars, and free-floating planets. These events offer a unique window into the dark population of our Galaxy, including possible primordial black holes and candidates for dark matter. Observations from the Gaia satellite, launched by ESA in 2013, have been instrumental in detecting these rare events, and future data releases (DR4 and DR5) promise even more discoveries. In this presentation, I will introduce the BHTOM system and highlight the vital role of small telescopes and amateur astronomers in monitoring Gaia-discovered microlensing events such as Gaia16aye, Gaia18cbf, Gaia19bld, Gaia19dke, and AT2021uey. These collaborative efforts have led to detailed studies of the lensing objects’ masses and distances, demonstrating how small telescopes, when used together, can achieve big science. This talk aims to inspire and invite more amateur observers to join this growing international effort.