LAMOST spectral survey contains two main parts: the LAMOST ExtraGAlactic Survey (LEGAS), and the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey of Milky Way stellar structure. The unique design of LAMOST enables it to take 4000 spectra in a single exposure.
LAMOST has been renamed as ‘Guo Shou Jing Telescope’ in 2010, Guo Shou Jing was a Chinese astronomer, engineer, and mathematician who lived during the Yuan Dynasty (1271–1368).
LAMOST DR2 totally releases 4,133,190 spectra, include 906,562 objects of the pilot survey (2011-10-24~2012-06-17), 1,637,977 objects of the first-year regular survey (2012-09-28~2013-06-03), and 1,588,651 objects of the second-year regular survey (2013-09-10~2014-06-03). Similar as DR1, DR2 also includes two types of data: optical spectra (flux- and wavelength-calibrated, sky-subtracted), and catalog data, which includes both parameters measure from spectra, such as redshifts and signal to noise ratios, and parameters inherited from input catalogs. You should keep in mind that LAMOST is a spectral survey telescope, and the parameters related to photometry, which you get here, all come from other surveys.
If you have a question about the nature of the data, consult the
Data Description page.
Frequently Asked Questions (FAQ)
in this page provides answers to common questions about the LAMOST DR2, and our data access tools.
Query Introduction tells you not only how to search for information you want but also what the tools mean.
This page shows what areas of sky (sky coverage) are included in LAMOST DR2.
When you search for data in LAMOST DR2, you are going through the LAMOST DR2 database and looking for objects that match criteria you choose. For simple searches of spectra, use
catalog search and the
Query Introduction. For more complex searches, use
If you have a fairly small list of objects to match - a few hundred or so - use the
catalog search tool. Paste your list of objects, or upload a file containing 3 columns of ra,dec,radius in format
Query Introduction tells you. Click Search. The next page will show only those objects that appear in the LAMOST DR2.
The format of LAMOST DR2 FITS files are similar as SDSS FITS files. You can get the wavelengths of FITS files through reading the FITS
header. Totally, there are three keywords related to wavelength:
NAXIS1 keyword represents the number of wavelength array, the
COEFF0 keyword represents the central wavelength (log10) of first pixel, and the
COEFF1 keyword represents the dispersion (log10) between every two pixels. You should be careful that both
COEFF1 are given in log10-scale.
IRAF package has been traditionally used in astronomy. For LAMOST DR2 data, the splot task can be used to view individual spectrum files. However, splot only understands spectrum files formatted in a specific way. In LAMOST DR2,
spec files were formatted in a manner consistent with splot.
Catalog data summarize quantities measured from the spectra such as redshifts, signal to noise ratios, and object classifications. These are available either from the
Catalog Search database, or as binary tables in FITS and CSV file formats.You can find them
here, and read them by any common FITS-read softwares.
The catalogs of ‘A F G K’ type stars, ‘A’ type stars, and ’M’ type stars are all subsets of the LAMOST general catalog, you can find the details
mag1 to mag7mean? (How can I get the magnitude I need?)
The targets of LAMOST DR2 are provided by different astronomers, and they are from various photometric catalogs, e.g. SDSS, 2MASS, NVSS, Kepler, etc. Thus,
magtype follows and reflects the variety of targets selection.
You can search for the magnitudes according to
magtype. For example, if you set
magtype as ‘ugrizjh’, then you get ‘mag1’ as magnitude in SDSS u-band, ‘mag2’ as magnitude in g-band, ‘mag3’ as magnitude in r-band, ‘mag4’ as magnitude in i-band, ‘mag5’ as magnitude in z-band, ‘mag6’ as magnitude in j-band, and ‘mag7’ as magnitude in h-band. Besides, if you set
magtype as ‘griz’, then you get ‘mag1’ as magnitude in g-band, ‘mag2’ as magnitude in r-band, ‘mag3’ as magnitude in i-band, ‘mag4’ as magnitude in z-band, and ‘mag5’, ‘mag6’, ‘mag7’ all as NULL.
View Spectrum page requires that your browser supports HTML5. Please use the latest version of browsers. In our tests,
Internet Explorer could work.
1) Please install
Java Runtime Environment.
2) The specview is self-signed, please add
http://dr2.lamost.org to your
Java Exception SiteList.