System Description and First Light Curves of the Hungarian Automated Telescope, an Autonomous Observatory for Variability Search

Having been operational at Kitt Peak for more than a year, the prototype (HAT‐1) of the Hungarian Automated Telescope (HAT) has been used for an all‐sky variability search of the northern hemisphere. This small autonomous observatory is recording the brightness of stars in the range of I C ≈ 6–13 mag with a telephoto lens and its 9 ° × 9 ° field of view, yielding a data rate of ∼10 6 photometric measurements per night. We give brief hardware and software descriptions of the system, controlled by a single PC running RealTime Linux OS. We provide an overview of site‐specific details and quantify the astrometric and photometric capabilities of HAT. As a demonstration of system performance, we give a sample of 60 short‐period variables in a single selected field, all bright, with I <13 mag, where only 14 were known before. Depending on the observing strategy, a search for extrasolar planet transits is also a feasible observing program. We conclude with a short discussion on future directions. Further information can be found at the HAT Web page. 3