Over its long history, the James Gregory Telescope has observed many different types of astronomical targets: galaxies, contact binaries, active galactic nuclei, minor planets, novae, and spotted stars. The research themes are changing and so is the observing program at the JGT. In recent years we are mostly observing for the following programs:
Discovery of exoplanets: Planets around stars other than the Sun can in most cases not be seen directly, but they can be observed by indirect means. When exoplanets eclipse their host star, they cause a characteristic dip in the brightness of the star (see image). This dip – not more than one or two percent – can be measured by taking images of the star over and over throughout the night and monitor its brightness. With the JGT our aim is to confirm or reject exoplanet candidates found by the Super-WASP collaboration. This requires about 5 hours of clear sky to catch the planet as it is passing in front of its star.
Monitoring young stars: Young stars are variable. Their brightness can change dramatically over timescales of days, quite different from the Sun. From these brightness changes we can infer the rotation periods of young stars, their surface properties and gain insights about the way these stars accumulate material from their surroundings. Every winter we observe star forming regions containing hundreds of young stars, as part of the multi-site project HOYS. These images are analysed in undergraduate courses and the results are fed into the HOYS database.
Galactic Plane survey: In 2018 we initiated the first large-scale survey program at the JGT, making use of the wide-field camera mounted in the original focal plane. In the Fleming Survey, we monitor fields in the Galactic Plane for up to 4 hours, to find short-term variables, detect solar system objects, and also to comb the sky for space debris (see below).
Space debris monitoring: The Earth is orbited by millions of man-made things. This includes about a thousand active satellites, but also a huge amount of debris, accumulated over 7 decades since the first satellite launch. Discovering, tracking, and eventually removing space debris from the orbits is critical for the future of human space exploration. With the JGT we are studying the frequency and properties of debris on the barely explored high-inclination Molniya-type orbits.
The shapes of asteroids: Asteroids are minor planets, small rocky bodies orbiting the Sun. The light we receive from minor planets is sun light reflected off their surfaces. Its intensity varies over time, depending on rotational phase and shape of the asteroid. Since 2015 we are feeding high-precision lightcurves of asteroids to the Observatoire de Geneva to aid in deriving the three-dimensional shapes of minor planets.