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. |
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Name | Unit | Data Type | Size | Default Value | Description |
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objID | dimensionless | BIGINT | 8 | NA | Unique object identifier used to join to ObjectThin. |
mdra | 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 | 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. |
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 | astrometry corrected replacement for raMeanErr in ObjectThin: Standard deviation in RA from weighted single epoch errors. Value is converted to arcsec in ObjectThin. |
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 | astrometry corrected replacement for posMeanChisq in ObjectThin = (chisqra+chisqdec)/2: Reduced chi-square in RA PM fit |
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. |
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. | |||||
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. |