ANU researchers have had detailed input into the design and construction of the SkyMapper telescope, which was built by Canberra-based company EOS at its Arizona plant, while technicians from the University have assembled a powerful digital camera to work in tandem with the instrument.
The automatic telescope will use clever software to complete its mission, and a customised data pipe to shunt information back to mission control in Canberra.
Over the last seven years the project has been driven by a team of astronomy researchers: Professor Brian Schmidt, Professor Mike Bessell, Professor Gary Da Costa, Dr Paul Francis, Dr Stefan Keller and Dr Patrick Tisserand.
Two members of that team talk to ANU Reporter about the origins of SkyMapper and where the project is headed.
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Origins
Professor Brian Schmidt from the Research School of Astronomy and Astrophysics (RSAA) at ANU has been involved with many aspects of SkyMapper since the inception of the project, including managing the procurement of the telescope, overseeing the development of the 268 Megapixel SkyMapper Camera, overseeing the development of the data pipeline, and making sure that everything works smoothly once the Southern Sky Survey gets underway.
Professor Brian Schmidt. Photo: Belinda Pratten
ANU Reporter: SkyMapper is about to come online after several years in development. How does it feel to be at the threshold?
Brian Schmidt: There is a real sense of anticipation. The data are going to be absolutely fantastic, and I think we are all just waiting to jump head first into the Terabytes of information.
Tell us about the origins of the project? What knowledge gap will it help to fill?
In 2002 we at RSAA successfully applied for a grant from the Australian Research Council to do a more modest survey of the southern Sky using the Great Melbourne Telescope. This was to provide the first digital map of the southern sky, and to allow us to tackle many of the big questions in astronomy that we couldn’t previously for lack of an accurate census of the southern skies. On the 18th of January 2003, 18 days after this grant started, the Great Melbourne Telescope and much of the Mt Stromlo Observatory near Canberra was destroyed by fire, and with it, the Southern Sky Survey. SkyMapper was part of Stromlo’s rebirth from the ashes, as an international leading project that would involve many people from RSAA.
How involved were ANU researchers in the design process? Can you describe the relationship with the developers at EOS?
More than 20 members of ANU staff have been involved in the SkyMapper project, in both scientific and technical capacities. This project team has worked on all aspects of the program, designing and building the giant camera, the software systems, and helping to define the telescope requirements. Our relationship with EOS has been a good one. Building a telescope like SkyMapper had never been done before, and so the cooperation between our team and theirs about how to get a useful telescope has been key to the project’s success.
SkyMapper saw its first light during testing in Arizona in 2007. How did it perform?
First light in 2007 was a great first step, but it was a baby step, compared to our acceptance of telescope in February, this year, at Siding Spring Observatory. The telescope performed admirably, pointing to the stars it was asked to follow, remaining in focus, and providing very high quality images. This was a huge step and means we only have to wait for our own digital camera to be put on the back-end of the telescope.
Can you describe the journey of the telescope to Australia and the installation process at Siding Spring?
After being tested in Tucson, Arizona, the telescope was disassembled into several large pieces, packed in crates, and shipped to Australia at the beginning of July 2008. After clearing Customs, it arrived at Siding Spring in the same shipping containers, and was then installed into the telescope dome in just a few days last September. Re-aligning of the telescope then commenced in October, such that the telescope was producing good images within a few weeks. The final tweaks happened just after Christmas, and led to the completed telescope being handed over to the ANU in February.
Can you explain how the instrument will work?
SkyMapper will be fully automated, which means that it will look at the weather and decide if it is OK to open. Once open, it has a scheduler that does it best to observe the things that astronomers want it to look at. It makes sensible decisions on what should be looked at any given time based on the position of the object, the weather, and things like how much moonlight there is. The data are transported down to Canberra via a Gigabit link to be processed, with care, at RSAA.
How significant is this instrument and project for Australian astronomy?
It certainly should be one of the big projects in Australian astronomy’s history. It will be used by a substantial fraction of the country’s astronomers one way or another, and by large number of overseas researchers as well. We hope it will help make lots of exciting new discoveries about our solar system, the Galaxy, and the evolution of the Universe in its total.
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Outcomes
Dr Stefan Keller from RSAA has led the effort to develop the software that will convert the massive amount of data gathered by SkyMapper down to a series of positions and brightnesses . Along the way he’s also become a passionate advocate for SkyMapper and the Southern Sky Survey.
Dr Stefan Keller. Photo: Stuart Hay
ANU Reporter: How does SkyMapper differ from other telescopes. How will it work?
Stefan Keller: SkyMapper is among the first of a new breed of telescopes that are coming on line around the world over the next decade. It is a dedicated survey telescope that will robotically survey the southern sky. The telescope is of relatively modest size but it is the cutting-edge detector technology that sets SkyMapper apart from telescopes that have gone before. The SkyMapper camera enables us to capture enormous numbers of stars in each exposure by covering an area 40 times larger than the full moon every minute.
What is the Southern Sky Survey? How long will it take?
The Southern Sky Survey is the first digital map of the southern sky as it appears in visual light. We will acquire the image of 4000 fields to form a mosaic of the sky and we will do this in six specially designed optical filters to isolate particular colours of light. This will provide information on the shape, position and colours of all the stars and galaxies in our images. To investigate pulsating stars, asteroids and exploding stars or supernovae we will take a series of images at different times. An asteroid, for instance, can be clearly seen as a moving point of light using this technique. In total, the survey will take five years to complete.
What exactly are you looking for during the survey?
This project is an iconic data set for astronomers here and around the world. This is perhaps the most exciting thing about the program - there is so much we can do with these data. Personally, I will be looking for extremely old stars, stars that are left over from the very first generations of stars to form in the Universe. These stars are essentially time capsules of material from shortly after the Big Bang 13.7 billion years ago. These stars retain not only their chemical composition from this early time but also possess characteristic motions that can provide us important clues as to how we construct a galaxy like the Milky Way.
Can you describe the quality of the data you’ll be capturing?
We will be probing the Universe to a depth a million times fainter than accessible with the human eye. This is a huge amount of information of the order of 400 Terabytes or approximately 100000 DVDs of data. SkyMapper’s niche is understanding the stellar populations of the Milky Way and nearby galaxies. By a clever design of our filter set we have produced a system that provides unparalleled resolution of the fundamental stellar properties: a star’s temperature, density and elemental abundance. This will enable us to dissect the stars of the Milky Way and understand the process of assembly of the Milky Way in detail that has never being achieved before.
Where will information from the survey be stored? Who will be able to access it, and what kinds of applications will it be used for?
The huge amount of data will be processed and stored at the ANU super computing facility. After a period of data quality control we will make the data set freely available to the world via the Internet - any one can access it. Once it goes public we are sure it will be used for scientific purposes that we, the SkyMapper team, can’t even imagine - that is the way of science!
How significant is this instrument and project for Australian astronomy?
The data set that SkyMapper will produce is extremely important for Australian astronomers. For the ANU it is signal of our ability to design, construct and produce cutting-edge science. It looks forward to the next generation of extremely large telescopes such as the Giant Magellan Telescope with 25m diameter mirrors, a project to which the ANU is a founding partner. Telescopes such as the Giant Magellan Telescope will target objects selected from the SkyMapper positions and brightnesses of stars and galaxies.
How do you feel now that the long wait for turning SkyMapper on is almost over?
Well there is a tremendous sense of anticipation. When SkyMapper switches on the data flow it will generate will be like drinking from a fire hose. This is a huge opportunity for an early career researcher such as myself to be involved at the start of something very big and full of new science to explore.
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Partners
Dr Craig Smith is the CEO of EOS Space Systems, the company commissioned to build the SkyMapper telescope. The Canberra-based company assembled the instrument at its plant in Tuscon, Arizona and oversaw installation at Siding Spring.
ANU Reporter: How has the SkyMapper construction process compare to other EOS projects to date?
Craig Smith: They all have their challenges. This one is some of the largest transmissive optics we’ve ever dealt with. We’ve had to build corrective lenses to get very wide fields of view. It’s had its own unique challenges. There were a lot of details in planning and design and tolerance.
How does it go from idea to finished instrument?
Researchers at ANU tells us what their ultimate objective is. They then work with our design team to try to come up with cost-effective system that will do the job. Then we get down to the hard part adjusting for tolerance, or making sure that the allowed arrors are controlled so that the system works together.
How feel to be involved in this flagship Australian astronomy project?
We’re always very happy to support Australian projects and proud to be part of it. It’s good for Australia and good for us.
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