The United Kingdom Infrared Telescope's (UKIRT) Wide Field Camera (WFCAM) atop Hawaii's Mauna Kea has reached a major milestone. WFCAM took its one-millionth observation on the 31st of October, after more than two years of observations of the infrared Universe. The millionth frame was part of a program aiming to find planets around low-mass stars.

The millionth observation actually means four million individual infrared frames, because WFCAM focuses infrared light onto four detectors, which take an image for each observation.

Brad Cavanagh, the software engineer responsible for WFCAM data at the Joint Astronomy Centre (JAC), said that "a million WFCAM observations corresponds to about sixteen trillion pixels. If you had a six-megapixel digital camera and took one picture every second, you would have to take 2,796,200 pictures, and it would take over 32 days to do it. The one million observations add up to a little over 60 Terabytes of data. If you wanted to put all of the data on CDs you'd need to buy 98,461 of them, and they'd make a stack over 387 feet high, which is over one and a quarter football fields long. If you wanted to download all the data to your computer over a 2 megabit/sec cable internet connection it would take eight years and 41 days."

WFCAM was delivered to UKIRT in late 2004 and has been in active operation since Spring 2005. In two years of operation - sharing the telescope about equally with other observing modes - WFCAM has taken 30 times the amount of data taken in the entire 25-year history of the telescope before its arrival.

UKIRT with WFCAM is undertaking both a world-leading sky survey in the infrared (UKIRT Infrared Deep Sky Survey, UKIDSS), a large range of specific projects for individual astronomers, and most recently a set of very large campaign projects aimed at a range of scientific targets including Earth-like planets and star formation in the early Universe.

Dr. Tom Kerr, the WFCAM Instrument Scientist, says that the mass production of astronomical data was exactly what WFCAM was intended for: "WFCAM, coupled with UKIRT, has been delivering enormous amounts of data over the past two years. The great majority of the images have formed part of the UKIRT Infrared Deep Sky Survey, or UKIDSS - an extraordinarily ambitious 7-year programme to survey the Universe at Infrared wavelengths, going to unprecedented depths to detect both the closest objects outside the solar system, the most distant galaxies and quasars, and plenty in between. Our millionth WFCAM observation, taken the other night, in fact contributed to a different but equally exciting project surveying relatively local, faint red stars looking for transits of exoplanets from multiple Jupiters down to small, rocky bodies like the Earth."

These stars are much better observed in the infrared, because they have much lower temperatures than stars like our sun. Because they are also very small and relatively faint, the signature of a planet transiting across the face of the disk is much easier to detect - it has greater contrast and lasts an hour or two. Given the comparatively large field of view of WFCAM, there are not only expected to be good numbers of transits, but there are also hundreds of non-variable stars in each field, by comparison with which the very slight brightness dips due to the transits can be precisely measured. The one-millionth observation by itself contains thousands of stars per chip.

Dr. Simon Hodgkin from the Institute of Astronomy in Cambridge (UK) says that "with the WFCAM transit survey we are attempting to search for planets orbiting around dim stars which are 2-10 times smaller and fainter than our own Sun and very much more common. The aim of the project is to see if planets can easily form around such faint and low mass stars, or if there is something special and rare about the kind of star that can host a solar system. WFCAM on UKIRT provides the perfect combination of large field of view and high sensitivity to infrared light from such faint stars. We will image 10's of thousands of faint stars, thousands of times each, and will search for the tiny changes in brightness associated with the passage of a planet across the stellar disk - a transit. Our survey is even sensitive enough to be able to discover planets only a little larger than the Earth, if they commonly form around and close in to their low mass host stars."

He reports that "WFCAM has already taken many many more images in two and a half years of operation than most telescopes have achieved in their entire lifetimes. This is because WFCAM takes short exposures of the sky every 10 seconds, whereas most optical telescopes will take exposures that last for 10 minutes or even an hour. This ability to take many exposures in quick succession is vital to the design of the WFCAM transit survey."

Professor Gary Davis, Director of the Joint Astronomy Centre, points out that WFCAM is one of the instruments keeping UKIRT at the forefront of infrared astronomy. "Survey programs such as UKIDSS and the WFCAM Transit Survey are producing huge amounts of high-quality data, which will not only serve immediate research goals, but will also provide a resource of enormous scope and potential for the astronomical community at large."

Images: 1. This image is a zoomed-out view of the observation. It shows the millionth observation images contributed by the four WFCAM detectors.

2. This image is a zoomed-in full resolution section of the field. We see mostly stars, but the fuzzy patches are distant galaxies.

3. This image shows a close-up of two of the distant galaxies among the field of stars.

4. The United Kingdom Infrared Telescope on Mauna Kea, Hawaii.

5. The Wide Field Camera (long black tube) on the United Kingdom Infrared Telescope on Mauna Kea, Hawaii.

These images can be found at http://outreach.jach.hawaii.edu/pressroom/2007_onemillion/

Notes for Editors:

UKIDSS

UKIDSS is expected to be completed by 2012, by which time it will have covered almost a quarter of the sky and hopefully further explored the cool, low-mass objects that are defined somewhere between stars and planets.

UKIRT

The United Kingdom Infrared Telescope (UKIRT) with its 3.8-metre (12.5-foot) mirror is the world's largest telescope dedicated solely to infrared astronomy. The telescope is located near the summit of Mauna Kea, Hawaii, at an altitude of 4194 metres (13760 feet) above sea level. It is operated by the Joint Astronomy Centre in Hilo, Hawaii, on behalf of the UK Science and Technology Facilities Council. More about the UK Infrared Telescope can be found at http://outreach.jach.hawaii.edu/articles/aboutukirt/

The UK ATC

The UK Astronomy Technology Centre is located at the Royal Observatory, Edinburgh (ROE). It is a scientific site belonging to the Science and Technology Facilities Council. The mission of the UK ATC is to support the mission and strategic aims of the Science and Technology Facilities Council and to help keep the UK at the forefront of world astronomy by providing a UK focus for the design, production and promotion of state of the art astronomical technology.

Science and Technology Facilities Council

The Science and Technology Facilities Council is an independent, non-departmental public body of the Office of Science and Innovation which itself is part of the Department of Trade and Industry. It was formed as a new Research Council on 1 April 2007 through a merger of the Council for the Central Laboratory of the Research Councils (CCLRC) and the Particle Physics and Astronomy Research Council (PPARC) and the transfer of responsibility for nuclear physics from the Engineering and Physical Sciences Research Council (EPSRC). We are one of seven national research councils in the UK.

The Science and Technology Facilities Council is government funded and provides research grants and studentships to scientists in British universities, gives researchers access to world-class facilities and funds the UK membership of international bodies such as the European Organisation for Nuclear Research, CERN, the European Space Agency and the European Southern Observatory. It also contributes money for the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, the UK Astronomy Technology Centre at the Royal Observatory, Edinburgh and the MERLIN/VLBI National Facility.

Media Contacts

Please note that it is best to contact these individuals by email.

Inge Heyer
Science Outreach Specialist
Joint Astronomy Centre
University Park
660 N. A'ohoku Place
Hilo, HI 96720 USA
Desk 1-808-969-6524
FAX 1-808-961-6516
Email: i.heyer@jach.hawaii.edu

Science Contacts

Please note that it is best to contact these individuals by email.

Dr. Tom Kerr
Joint Astronomy Centre
University Park
660 N. A'ohoku Place
Hilo, HI 96720 USA
Tel 1-808-969-6570
FAX 1-808-961-6516
Email: t.kerr@jach.hawaii.edu

Mr. Brad Cavanagh
Joint Astronomy Centre
University Park
660 N. A'ohoku Place
Hilo, HI 96720 USA
Tel 1-808-969-6555
FAX 1-808-961-6516
Email: b.cavanagh@jach.hawaii.edu

Dr. Simon Hodgkin
Cambridge Astronomical Survey Unit
Institute of Astronomy, Madingley Road
Cambridge, CB3 0HA UK
Tel: +44 (0)1223 766657
Fax: +44 (0)1223 337523
Email: sth@ast.cam.ac.uk

Web Links:

Joint Astronomy Centre http://www.jach.hawaii.edu

Joint Astronomy Centre public outreach and press site http://www.jach.hawaii.edu/outreach

United Kingdom Astronomy Technology Centre http://www.roe.ac.uk/atc/

Science and Technology Facilities Council http://www.stfc.ac.uk/