MASCARA

Built and operated by Leiden University, the Netherlands, MASCARA (the Multi-site All-Sky CAmeRA) was a planet-hunting instrument that consisted of two individual stations, one operating in each hemisphere. Each station contained a battery of cameras in a temperature-controlled enclosure which monitored almost the entire sky visible from its location. MASCARA’s cameras could remain fixed while in operation, with no need to track the stars across the sky as other telescopes do; they made use of short exposures (3–6 seconds) to avoid stars producing trails on the detector.

MASCARA had two stations in operation. The first station, in the northern hemisphere on the Roque de los Muchachos Observatory, on the island of La Palma in the Canary Islands, was fully operational since February 2015. The second station took advantage of the excellent observing conditions at ESO’s La Silla Observatory in Chile, and started operating in July 2017. 

With both stations installed, MASCARA could obtain an all-sky coverage, monitoring all stars down to magnitude 8.4. Both telescopes are now decommissioned.

Science goals

MASCARA’s low-cost design appeared unassuming, but it was innovative, flexible, and highly reliable. Consisting of five digital cameras with off-the-shelf components, this small planet-hunter took repeated measurements of thousands of stars and used software to hunt for the slight dimming of a star’s light as a planet crosses its disc. This exoplanet discovery method is called transit photometry.

The planet’s radius, mass and density can be directly determined by this method, and in very bright systems the planet's atmosphere can also be characterised.

The main purpose of MASCARA was to find exoplanets around the brightest stars in the sky, currently not probed by either space- or ground-based surveys. The target population for MASCARA consisted mostly of “hot Jupiters” — large worlds that are physically similar to Jupiter but orbit very close to their parent stars, resulting in high surface temperatures and orbital periods of only a few hours.

MASCARA also had the potential to discover super-Earths and Neptune-sized planets. The project provided a catalogue of the brightest nearby targets for future exoplanet characterisation missions, particularly for detailed observations of planetary atmospheres.

More about MASCARA

• Read more about this telescope on the MASCARA website (no longer active)
• Agreement to site MASCARA station at La Silla
• Science paper on the design and operation of MASCARA