LAMOST
Encyclopedia
The Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) is a meridian reflecting Schmidt telescope. Its optics comprise two roughly rectangular mirrors, each made up of a number of 1.1-metre hexagonal deformable segments, providing a focal plane 1.75 metres in diameter corresponding to a five-degree field of view. This focal plane is tiled with fibre-positioning units, attached to 4000 fibres which transfer light to sixteen spectrographs below. The larger spherical mirror MB (37 segments, fitting in a 6.67m x 6.09m rectangle) is located at an angle in a large slanted tunnel attached to a tower; the smaller corrector mirror MA (24 segments, fitting in a 5.72m x 4.4m rectangle) is in a dome at ground level.. Looking at the image opposite, MB is at the top of the left-hand supporting column of the tower, MA is in the left of the two domes at the right of the image (the rightmost, grey dome is an unrelated telescope), and the spectrographs are inside the right-hand column of the tower.
Each spectrograph has two 4k x 4k CCD cameras, using e2v
CCD chips, with 'blue' (370-590nm) and 'red' (570-900nm) sides; the telescope can also be used in a higher spectral resolution mode where the range is 510-540 and 830-890nm .
Using active optics technique to control its reflecting corrector makes it a unique astronomical instrument in combining large aperture with wide field of view. The available large focal plane may accommodate up to thousands of fibers, by which the collected light of distant and faint celestial objects down to 20.5 magnitude is fed into the spectrographs, promising a very high spectrum acquiring rate of ten-thousands of spectra per night. The telescope is located at the Xinglong Station of National Astronomical Observatories. The project’s budget is RMB 235 million yuan. It will bring Chinese astronomy into the 21century with a leading role in wide field spectroscopy and in the fields of large scale and large sample astronomy and astrophysics.
It is also hoped that the vast volume of data produced will lead to additional serendipitous discoveries. Early commissioning observations have been able to confirm spectroscopically a new way of identifying quasars based on their infrared color:
Each spectrograph has two 4k x 4k CCD cameras, using e2v
E2v
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CCD chips, with 'blue' (370-590nm) and 'red' (570-900nm) sides; the telescope can also be used in a higher spectral resolution mode where the range is 510-540 and 830-890nm .
Using active optics technique to control its reflecting corrector makes it a unique astronomical instrument in combining large aperture with wide field of view. The available large focal plane may accommodate up to thousands of fibers, by which the collected light of distant and faint celestial objects down to 20.5 magnitude is fed into the spectrographs, promising a very high spectrum acquiring rate of ten-thousands of spectra per night. The telescope is located at the Xinglong Station of National Astronomical Observatories. The project’s budget is RMB 235 million yuan. It will bring Chinese astronomy into the 21century with a leading role in wide field spectroscopy and in the fields of large scale and large sample astronomy and astrophysics.
Scientific goals
Particular scientific goals of the LAMOST include:- Extra-galactic spectroscopic survey — Large scale structure of the universe
- Stellar spectroscopic survey — Structure of the Galaxy, including metal poor stars search in the galactic halo
- Cross identification of multi-waveband surveys
It is also hoped that the vast volume of data produced will lead to additional serendipitous discoveries. Early commissioning observations have been able to confirm spectroscopically a new way of identifying quasars based on their infrared color: