New telescope to map southern skies
A replacement for Australia's oldest telescope, destroyed in last year's Canberra bushfires, is set to produce the world's first comprehensive digital map of the southern sky.
The Mount Stromlo Observatory lost, among other things, its 1868 Great Melbourne Telescope, in the bushfires that hit Canberra on 18 January 2003.
SkyMapper is a 1.3 metre optical telescope that will provide detailed maps of the southern sky five times faster than existing telescopes.
The digital information collected in the Southern Sky Survey will not only record the position of every object in the southern sky, but also its temperature and chemical composition.
Southern Sky Survey leader Professor Brian Schmidt of the ANU described the survey as a 'census' of the sky, which will help astronomers select objects to study.
"The reason you do a census of Australia is you need to understand the whole picture to make sensible decisions on what to do next," Schmidt told ABC Science Online.
He said the census would allow astronomers to identify some of the most distant objects in the universe, quasars "so we can study the birth of galaxies on the edge of the visible universe".
Similarly, the telescope would help pinpoint the nearest asteroids to Earth to study, identify planets in the Solar System beyond Pluto, and find other stars in our galaxy that look like the Sun.
"Hopefully it's going to provide us an unprecedented understanding of how our gGalaxy formed in itself," Schmidt said. "By looking at that complete census we can see how the galaxy came together."
SkyMapper will help astronomers to see objects a million times fainter and in 4000 times more detail than can be seen by the human eye. Astronomers will use six colours to pinpoint properties of stars and galaxies.
The telescope will be able to image a patch of the sky 25 times the size of the full moon in one snap, and will record pictures with a 320 million pixel camera.
SkyMapper is expected to be operational by late 2006. The first map produced will image objects only 10,000 fainter than can be seen by the human eye and it will take about three years to get a map that shows the desired detail.
The telescope will end up focussing on each of 4000 patches of sky for about 10 minutes, Schmidt said.
"We hope to have the whole thing completed and wrapped up by 2010 but will be presenting the sky as we map it over time so every year the map will get a bit deeper and a bit more complete."
SkyMapper will complement work done by the US$100 million (A$143 million) Sloan Digital Sky Survey in New Mexico, which has mapped about one quarter of the northern sky, said Schmidt.
Queanbeyan company Electro Optic Systems will construct the telescope and Mount Stromlo staff will build the camera.
SkyMapper data will be shared with astronomers around the world via the Virtual Observatory initiative.