14.4.6 sdssdr9_original_valid
sdssdr9_oid : Unique Numeric Identifier (long)
Incremental unique numeric identifier (increasing with declination).
This is the only field which was not in the original SDSS DR9 catalogue, but was added for cross-match purposes.
obj_id : Unique SDSS identifier (string)
A number identifying an object in the image catalog for DR9. It is a bit-encoded integer of run, rerun, camcol, field, object.
The bits are assigned in objid as follows:
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5962 skyVersion resolved sky version
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4858 rerun, number of pipeline rerun
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2931 camcol, camera column (1-6)
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1627 field, field number within run
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015 id, object number within field
thing_id : Unique identifier from global resolve (long)
Each unique source in the SDSS catalog is identified by the thing_id. Each source may have been observed more than once in multiple runs, and might therefore have multiple detections listed in the catalog. Only one detection is considered primary.
ra : RA (double, Angle[deg])
J2000 Right Ascension (from r-band, or best other band if r-band if too faint or saturated in r).
dec : DEC (double, Angle[deg])
J2000 Declination (from r-band, or best other band if r-band if too faint or saturated in r).
ra_error : Reference error in RAcosDEC (double, Angle[arcsec])
dec_error : Reference error in DEC (double, Angle[arcsec])
mjd : Date of observation (double, Time[day])
Modified Julian Date, used to indicate the date that a given piece of SDSS data (image or spectrum) was taken.
u_mag : PSF magnitude in the u band (double, Magnitude[mag])
For isolated stars, which are well-described by the point spread function (PSF), the optimal measure of the total flux is determined by fitting a PSF model to the object.
u_mag_error : error on PSF magnitude in the u band (double, Magnitude[mag])
g_mag : PSF magnitude in the g band (double, Magnitude[mag])
For isolated stars, which are well-described by the point spread function (PSF), the optimal measure of the total flux is determined by fitting a PSF model to the object.
g_mag_error : error on PSF magnitude in the g band (double, Magnitude[mag])
r_mag : PSF magnitude in the r band (double, Magnitude[mag])
For isolated stars, which are well-described by the point spread function (PSF), the optimal measure of the total flux is determined by fitting a PSF model to the object.
r_mag_error : error on PSF magnitude in the r band (double, Magnitude[mag])
i_mag : PSF magnitude in the i band (double, Magnitude[mag])
For isolated stars, which are well-described by the point spread function (PSF), the optimal measure of the total flux is determined by fitting a PSF model to the object.
i_mag_error : error on PSF magnitude in the i band (double, Magnitude[mag])
z_mag : PSF magnitude in the z band (double, Magnitude[mag])
For isolated stars, which are well-described by the point spread function (PSF), the optimal measure of the total flux is determined by fitting a PSF model to the object.
z_mag_error : error on PSF magnitude in the z band (double, Magnitude[mag])
objc_type : type classification of the object (int)
Distinguishes stars (type=6) and galaxies (type=3) based on their morphology. It is quantified on the basis of the difference between the PSF and model magnitudes.
clean_flag : clean photometry flag for point sources (int)
Clean photometry flag for point sources (1=clean, 0=unclean).