The starting point for the PS1 data archive is at Pan-STARRS1 data archive home page.
Description: Contains metadata for objects that have had their astrometry corrected using Gaia EDR3. This table contains the original values from the ObjectThin table that have been updated, the replacement values that are in ObjectThin (highlighted in the comments), as well as additional information on the new astrometry. See PS1 Astrometry Correction Using Gaia EDR3 for details. Most users will simply use the updated values in ObjectThin; the values in this table may be useful for ongoing research projects that rely on details of the original PS1 DR2 positions. mdra astrometry corrected replacement for epochMean in ObjectThin: Modified Julian Date (MJD) of the mean epoch corresponding to positions and proper motions. This is the average of mdmjdra and mdmjddec. astrometry corrected replacement for raMeanErr in ObjectThin: Standard deviation in RA from weighted single epoch errors. Value is converted to arcsec in ObjectThin. astrometry corrected replacement for posMeanChisq in ObjectThin = (chisqra+chisqdec)/2: Reduced chi-square in RA PM fit Values for columns below are the original values from ObjectThin, copied before the astrometry update was applied. NOTE: When querying this table, if these original column values are all NULL it indicates that the object (objid) does not exist in ObjectThin. That applies mainly to objects south of declination -30 degrees.Name Unit Data Type Size Default Value Description objID dimensionless BIGINT 8 NA Unique object identifier used to join to ObjectThin. degrees FLOAT 8 NA Initial Right ascension position (J2000) determined from weighted mean of Detection positions (before Gaia correction). mddec degrees FLOAT 8 NA Initial Declination position (J2000) determined from weighted mean of Detection positions (before Gaia correction). mdmjd days FLOAT 8 NA mdmjdra days FLOAT 8 NA Weighted mean MJD for measurements that contributed to mdra. mdmjddec days FLOAT 8 NA Weighted mean MJD for measurements that contributed to mddec. nmd dimensionless INT 4 NA Number of detection measurements used. mdraErr milliarcseconds FLOAT 8 NA mddecErr milliarcseconds FLOAT 8 NA astrometry corrected replacement for raMeanErr in ObjectThin: Standard deviation in Dec from weighted single epoch errors. Value is converted to arcsec in ObjectThin. mdpmra milliarcseconds per year FLOAT 8 NA Proper motion in RA determined from weighted mean of Detection positions (before Gaia correction). mdpmdec milliarcseconds per year FLOAT 8 NA Proper motion in Dec determined from weighted mean of Detection positions (before Gaia correction). mdpmraErr milliarcseconds per year FLOAT 8 NA new column pmraErr in ObjectThin: Standard deviation in pmra from weighted single epoch errors. mdpmdecErr milliarcseconds per year FLOAT 8 NA new column pmdecErr in ObjectThin: Standard deviation in pmdec from weighted single epoch errors. chisqra dimensionless FLOAT 8 NA chisqdec dimensionless FLOAT 8 NA astrometry corrected replacement for posMeanChisq in ObjectThin = (chisqra+chisqdec)/2: Reduced chi-square in Dec PM fit dcr dimensionless BIT 1 NA Differential chromatic refraction correction applied: 1=yes, 0=no ra degrees FLOAT 8 NA astrometry corrected replacement for raMean in ObjectThin: RA from single epoch detections (weighted mean) in equinox J2000 at the mean epoch given by epochMean after correction using Gaia EDR3 using the algorithm described in the paper. dec degrees FLOAT 8 NA astrometry corrected replacement for decMean in ObjectThin: Dec from single epoch detections (weighted mean) in equinox J2000 at the mean epoch given by epochMean after correction using Gaia EDR3 using the algorithm described in the paper. pmra milliarcseconds per year FLOAT 8 NA new column pmra in ObjectThin: Proper motion in RA from single epoch detections after correction using Gaia EDR3 using the algorithm described in the paper. pmdec milliarcseconds per year FLOAT 8 NA new column pmdec in ObjectThin: Proper motion in Dec from single epoch detections after correction using Gaia EDR3 using the algorithm described in the paper. cx dimensionless FLOAT 8 NA astrometry corrected replacement for cx in ObjectThin: Cartesian x on a unit sphere. cy dimensionless FLOAT 8 NA astrometry corrected replacement for cy in ObjectThin: Cartesian y on a unit sphere. cz dimensionless FLOAT 8 NA astrometry corrected replacement for cz in ObjectThin: Cartesian z on a unit sphere. htmid dimensionless BIGINT 8 NA astrometry corrected replacement for htmID in ObjectThin: Hierarchical triangular mesh (Szalay 2007) index. raMean degrees FLOAT 8 -999 Right ascension from single epoch detections (weighted mean) in equinox J2000 at the mean epoch given by epochMean. decMean degrees FLOAT 8 -999 Declination from single epoch detections (weighted mean) in equinox J2000 at the mean epoch given by epochMean. raMeanErr arcsec REAL 4 -999 Right ascension standard deviation from single epoch detections. decMeanErr arcsec REAL 4 -999 Declination standard deviation from single epoch detections. epochMean days FLOAT 8 -999 Modified Julian Date of the mean epoch corresponding to raMean, decMean (equinox J2000). Note that Gaia DR1 data is sometimes included in the mean position (see the FAQ for details); in those cases, the epochMean value is near the Gaia DR1 epoch 2015.5 = MJD 15023. As a result, epochMean is not necessarily near the mean value of the PS1 measurement dates. That is no longer true of the new astrometry-corrected value of epochMean – the new positions do not include any Gaia position or epoch information in the calculations except to calibrate local disortions in the PS1 coordinate system. posMeanChisq dimensionless REAL 4 -999 Reduced chi squared value of mean position. cxOrig dimensionless FLOAT 8 NA Cartesian x on a unit sphere. cyOrig dimensionless FLOAT 8 NA Cartesian y on a unit sphere. czOrig dimensionless FLOAT 8 NA Cartesian z on a unit sphere. htmIDOrig dimensionless BIGINT 8 NA Hierarchical triangular mesh (Szalay 2007) index.