Camera captures out of this world images
Advances in our knowledge of planets in the outer reaches of our Solar system are being made thanks to an instrument created by experts at the University of Sheffield which observes high speed phenomena in outer space.
The instrument, known as the ULTRACAM, is an ultrafast, triple-beam three-colour camera for high-speed astrophysics. It has been used in hundreds of experiments across the world – including the first look of the dwarf planet Makemake which was published in the journal Nature this month and allowed astronomers to study its size, atmosphere and density.
The sophisticated camera takes many pictures a second in three colours and allows scientists to determine how large planets are by measuring how long it takes them to pass in front of a star, an event known as an occultation.
ULTRACAM is attached to two telescopes, one based in Chile and a second in the Canary Islands and is manned by staff from the University of Sheffield and the University of Warwick who watched as the dwarf planet blocked the light of distant star Nomad 1181-0235723, for about one minute
Dr Stuart Littlefair of the University’s Department of Physics and Astronomy, said: “In astronomy, it's hard to measure the size of something accurately. Especially so for the tiny 'dwarf planets' which orbit in the outer regions of the Solar system. A better way of measuring the size of these objects is to wait for rare events when one passes in front of a faint star. By measuring how long this event lasts, we can measure the size directly. If you measure how long this event lasts at different locations on the Earth, you can measure the shape of the object. You can also use these events to detect the presence of an atmosphere on the dwarf planets.
“Crucially, once you know how big the object is, you can work out how reflective it is, and make an educated guess about what the surface is made of. We have measured the size of Makemake to be two thirds the size of Pluto.
"Our value agrees with and is much more precise than previous estimates from Makemake's brightness alone. We have shown that Makemake is slightly elliptical in shape. It’s more reflective than Pluto, but less reflective than Pluto's twin, Eris. We have also shown that Makemake does not have an atmosphere like Pluto's.”
Dr Littlefair was at the telescope observing the event in Chile and performed the analysis to produce some of the data featured in the Nature paper.
The instrument was built by Professor Vik Dhillon of the University of Sheffield with Professor Tom Marsh of the University of Warwick and is used by both institutions.
To view the paper on line visit: http://www.nature.com/nature/journal/v491/n7425/full/nature11597.html
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