The Polar Bear Survey Telescope is an experiment to monitor light pollution in the sky over Armagh, to study variability in approximately 1000 stars close to the North Celestial Pole and to use this experiment as a tool to aid young people develop skills in science and technology.
· The primary motivation for this project is an Armagh Observatory commitment to monitor light pollution and its impact on the night sky over Armagh over the next decade or so.
· One requirement for calibration of the sky brightness is to use a standard source – the most obvious being fixed stars. The simplest system is to use the Pole Star as a primary reference, since this will be visible all the time the monitor is in operation.
· This choice enables an astronomical motivation. A system meeting the primary requirement could be capable of monitoring stars and galaxies for variability over timescales from minutes to years. Such surveys lead, inter alia, to discoveries of transiting exoplanets and eruptive variables (eg supernovae), accurate light curves and ephemerides for eclipsing and pulsating stars, and data for probing the structure of quasars.
· Therefore we have built a fixed telescope to monitor the brightness of at least 500 stars within a field centred on the North Celestial Pole (NCP). Observations will be taken in white light at least once every minute, at all hours of nautical darkness, aiming to achieve a photometric accuracy of better than 1%. The programme would enable light variability to be established over timescales from 5 minutes to 5 years.
· To meet a third Observatory objective, the telescope system and its outputs must be useful for enabling young people to develop skills in various aspects of science and technology. This can be achieved initially by making data frames and light curves available on-line, together with suitable data analysis tools.
· We therefore aim to develop a simple, robust but scientifically worthwhile system which can be duplicated cheaply. Experiments to monitor the sky in other locations would enrich science and skills training for a wider number of students.
· These objectives are roughly matched by observing the constellation of Ursa Minor – the little bear – continuously. Since Polaris forms the apex of this constellation – the name “Polar Bear Survey Telescope” has been adopted for the project.