SkyMapper
Encyclopedia
SkyMapper is a fully automated 1.35m wide-angle optical telescope
at Siding Spring Observatory
in northern New South Wales
, Australia. It is one of the telescopes of the Research School of Astronomy and Astrophysics
of the Australian National University
. The telescope has a compact modified Cassegrain
design with a large 0.69 m secondary mirror
, which gives it a very wide field of view: its single, dedicated instrument, a 268-million pixel imaging camera, can photograph 5.7 square degrees of sky. The camera has six filters which span from ultraviolet
to near infrared wavelengths.
The SkyMapper telescope was built to carry out the Southern Sky Survey, which will image the entire southern sky several times over in SkyMapper's six spectral filters over the course of five years. This survey will be analogous to the Sloan Digital Sky Survey
of the Northern hemisphere sky. It has several enhancements, including temporal coverage, more precise measurements of stellar properties and coverage of large parts of the plane of the Galaxy
.
. As the telescope has an alt-azimuth mounting, its dome is compact and snug: the minimum clearance as the telescope moves is about 4 cm.
chips, each with 2 x 4k pixels, arranged in a 4 x 8 array.
The six filters used to take observations are set in a photometric system
partly similar to that of the Sloan survey, to aid in comparison of the two sets of observations. These similar filters are the visible and near-infrared passbands named g, r, i and z. SkyMapper has additional, distinctive ultraviolet filters, a Strömgren system
-like u, and a unique narrow v near 4000Å. These two filters bracket the Balmer jump of stars' spectra, and allow the survey to detect the population of metal-poor stars within the Milky Way.
Optical telescope
An optical telescope is a telescope which is used to gather and focus light mainly from the visible part of the electromagnetic spectrum for directly viewing a magnified image for making a photograph, or collecting data through electronic image sensors....
at Siding Spring Observatory
Siding Spring Observatory
Siding Spring Observatory near Coonabarabran, New South Wales, Australia, part of the Research School of Astronomy & Astrophysics at the Australian National University , incorporates the Anglo-Australian Telescope along with a collection of other telescopes owned by the Australian National...
in northern New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, Australia. It is one of the telescopes of the Research School of Astronomy and Astrophysics
Mount Stromlo Observatory
Mount Stromlo Observatory located just outside of Canberra, Australia, is part of the Research School of Astronomy and Astrophysics at the Australian National University .-History:...
of the Australian National University
Australian National University
The Australian National University is a teaching and research university located in the Australian capital, Canberra.As of 2009, the ANU employs 3,945 administrative staff who teach approximately 10,000 undergraduates, and 7,500 postgraduate students...
. The telescope has a compact modified Cassegrain
Cassegrain reflector
The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas....
design with a large 0.69 m secondary mirror
Secondary mirror
A secondary mirror is the second deflecting or focusing mirror element in a reflecting telescope. Light gathered by the primary mirror is directed towards a focal point typically past the location of the secondary. Secondary mirrors in the form of an optically flat diagonal mirror are used to...
, which gives it a very wide field of view: its single, dedicated instrument, a 268-million pixel imaging camera, can photograph 5.7 square degrees of sky. The camera has six filters which span from ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
to near infrared wavelengths.
The SkyMapper telescope was built to carry out the Southern Sky Survey, which will image the entire southern sky several times over in SkyMapper's six spectral filters over the course of five years. This survey will be analogous to the Sloan Digital Sky Survey
Sloan Digital Sky Survey
The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project was named after the Alfred P...
of the Northern hemisphere sky. It has several enhancements, including temporal coverage, more precise measurements of stellar properties and coverage of large parts of the plane of the Galaxy
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
.
Telescope
The telescope and its dome were built by Electro Optics Systems of CanberraCanberra
Canberra is the capital city of Australia. With a population of over 345,000, it is Australia's largest inland city and the eighth-largest city overall. The city is located at the northern end of the Australian Capital Territory , south-west of Sydney, and north-east of Melbourne...
. As the telescope has an alt-azimuth mounting, its dome is compact and snug: the minimum clearance as the telescope moves is about 4 cm.
Camera and filters
The camera is a tiled mosaic of 32 CCDCCD
-Science:*Carbonate compensation depth, a property of oceans*Colony collapse disorder, a phenomenon involving the abrupt disappearance of the worker bees in a beehive or Western honey bee colony...
chips, each with 2 x 4k pixels, arranged in a 4 x 8 array.
The six filters used to take observations are set in a photometric system
Photometric system
In astronomy, a Photometric system is a set of well-defined passbands , with a known sensitivity to incident radiation. The sensitivity usually depends on the optical system, detectors and filters used. For each photometric system a set of primary standard stars is provided.The first known...
partly similar to that of the Sloan survey, to aid in comparison of the two sets of observations. These similar filters are the visible and near-infrared passbands named g, r, i and z. SkyMapper has additional, distinctive ultraviolet filters, a Strömgren system
Strömgren photometric system
Strömgren photometric system is four-colour medium-band photometric system for stellar classification. It was pioneered by the Danish astronomer Bengt Strömgren in 1956 and extended by his colleague the American astronomer David L...
-like u, and a unique narrow v near 4000Å. These two filters bracket the Balmer jump of stars' spectra, and allow the survey to detect the population of metal-poor stars within the Milky Way.