Astronomers See Double: the Gemini South Telescope

Press Release From: Particle Physics and Astronomy Research Council
Posted: Friday, January 18, 2002

A giant telescope with a whopping 8-metre diameter light collecting mirror opened its Cyclops eye on the Universe today [18 January]. Perched on the desolate summit of Cerro Pachon in the Chilean Andes at a height of 2737 metres [8,895 feet] the Gemini South telescope is an identical twin of Gemini North in Hawaii. The two telescopes, located each side of the equator, will enable UK astronomers to see double - and view the entire sky in both northern and southern hemispheres.

The Gemini telescopes, in which the UK has almost a quarter share through the Particle Physics and Astronomy Research Council [PPARC], have been designed to produce extremely sharp images of the Universe in the infrared waveband. Viewing in the infrared enables astronomers to see through the cosmic dust that obscures star forming regions and violent galaxies to reveal the inner secrets of stellar birth and the deep mysteries of the Universe. Each telescope also has an optical capability with 10 times the light gathering power of the Hubble Space Telescope. Coupled with high technology 'adaptive optics' instruments which will 'take the twinkling out of stars' the Gemini telescopes will produce images as sharp as those from space.

Commenting on the dedication of Gemini South, Prof. Ian Halliday, PPARC Chief Executive, said," This is a significant day for the Gemini telescopes and for the entire UK astronomy community. Britain is the second largest partner in the 7-country Gemini consortium. By taking a leading role in such international projects PPARC ensures that UK scientists have access to world-class facilities, enabling them to participate at the frontier of global astronomy research and discovery".

The UK has played a leading role in the design and construction of both telescopes and many of the scientific instruments on them, and several key individuals in the international consortium are British including the overall Gemini Project Director, Dr. Matt Mountain, formerly of the Royal Observatory Edinburgh.

'About a month ago we reached a milestone when both Gemini North and Gemini South made observations at the same time but in different parts of the sky invisible to each other,' said Dr Mountain. 'Today's dedication celebrates a decade of work by hundreds of people to build these two telescopes that have now become one observatory'.

UK astronomers have already begun to sample the new capabilities. Dr. Patrick Roche, [ UK Gemini Project Scientist at Oxford University], commented,' My colleague Dr Philip Lucas [University of Hertfordshire] and I have been fortunate to receive some of the early infrared images of star fields in Orion, which reach deeper than any other previous observations of the region and reveal many new and interesting structures in unprecedented detail. These and other data demonstrate that both Gemini telescopes meet their design requirements, delivering high sensitivity and exquisite image quality. We now look forward to a long and productive phase of scientific exploration'.

A further taster of discoveries to come from Gemini South was recently seen from its twin on Hawaii when it achieved a spectacular image dubbed 'the perfect spiral galaxy' using an instrument called GMOS [Gemini Multi-Object Spectrograph]. The dramatic image clearly demonstrated the power of Gemini's massive 8-metre light gathering mirror coupled with the 24 million ultra-sensitive pixel array of GMOS to capture beautiful astronomical phenomena. The UK's Astronomy Technology Centre [ATC], Durham University, and Canadian colleagues built the GMOS instrument.

'GMOS is one of the most significant scientific instruments ever built by the ATC,' said Dr Adrian Russell, ATC Director, ' and we are well advanced in building a twin for Gemini South, where we can expect similar exciting discoveries to come from the southern skies'.

For further information contact:

Peter Barratt
Head of Communications
Tel: 01793 442025 Email:

Gill Ormrod
Press Officer
Tel: 01793 442012 Email:

Gemini instruments
Technical - Colin Cunningham, UK ATC, Tel: 0131 668 8223,

Science - Rob Ivison, UK ATC, Tel: 0131 668 8361

Background notes.

* Images

The latest science images from Gemini South can be found at -

Further images are available from the PPARC website - or from Mark Wells Tel: 01793 442100 Email

1. Gemini South at Sunset
Credit: Gemini Observatory

2. A fish eye view of the Gemini South interior by daylight
Credit: Neelon Crawford

3. GMOS spiral galaxy
Credit: Gemini Observatory - GMOS Team

This image of NGC 628 (M-74) was obtained by the 8.1-metre Gemini North Telescope on Mauna Kea, Hawaii using the newly commissioned Gemini Multi-Object Spectrograph. To make the colour image, three images are combined to make this red, green and blue composite.

4. Prof. Ian Halliday, Chief Executive, Particle Physics and Astronomy Research Council Credit: PPARC

* Web addresses PPARC:
Gemini UK Support Group:
Gemini, core site:

* Whole sky coverage

Two telescopes, one in each hemisphere, provide access to the whole sky so that rare events which happen unpredictably anywhere in the sky [for example black-hole binary systems undergoing outbursts] can be followed with the northern or southern Gemini telescope.

* Best astronomical sites

The telescopes are sited high up, away from sources of terrestrial light pollution. The cold, dry, stable air above the Chilean and Hawaiian sites makes them outstanding locations for astronomy.

* Large light collecting mirrors

The 8.1-metre diameter mirrors provide large surface areas [50 square metres]. The mirrors are very thin [only 20 centimetres thick], and rely on a computer controlled support system to maintain their shape.

* Adaptive optics

Blurring of images [star twinkle] caused by the Earth's atmosphere can be compensated for by correcting in real time using adaptive optics [AO]. In the Gemini AO system the shape of the mirror is adjusted up to a hundred times a second to counteract the ripples in the light waves caused by atmospheric turbulence. This technique is most effective at infrared wavelengths where it will be a key component in providing sharp images.

The Gemini Observatory provides the astronomical communities in each partner country with state-of-the-art astronomical facilities that allocate observing time in proportion to each country's contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the UK Particle Physics and Astronomy Research Council (PPARC), the Canadian National Research Council (NRC), the Chilean Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT), the Australian Research Council (ARC), the Argentinean Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) and the Brazilian Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq). The Observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

The Particle Physics and Astronomy Research Council (PPARC) is the UK's strategic science investment agency. It funds research, education and public understanding in four areas of science - particle physics, astronomy, cosmology and space science.

PPARC 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 Laboratory for Particle Physics (CERN), and the European Space Agency. 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, which includes the Lovell Telescope at Jodrell Bank observatory.

PPARC's Public Understanding of Science and Technology Awards Scheme funds both small local projects and national initiatives aimed at improving public understanding of its areas of science.

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