LSST reference catalog schema description¶
The reference catalogs for use with LSST Data Management Science Pipelines have the following schema:
Catalog Schema¶
coord_ra
: ICRS position of star on sky (anlsst.geom.Angle
)
coord_dec
: ICRS position of star on sky (anlsst.geom.Angle
)
centroid
: position of star on an exposure, if relevant (anlsst.afw.Point2D
)
hasCentroid
: is centroid usable? (a Flag)
<referenceFilterName>_flux
: brightness in the specified reference catalog filter (nJy)Note: you can use astropy.units to convert from AB Magnitude to nJy:
u.Magnitude(value, u.ABmag).to_value(u.nJy)
<referenceFilterName>_fluxErr
(optional): brightness standard deviation (nJy); omitted if no data is available; possibly nan if data is available for some objects but not others
camFlux
: brightness in default camera filter (nJy); omitted ifdefaultFilter
not specified
camFluxErr
: brightness standard deviation for default camera filter; omitted ifdefaultFilter
not specified or standard deviation not available that filter
<cameraFilterName>_camFlux
: brightness in specified camera filter (nJy)
<cameraFilterName>_camFluxErr
(optional): brightness standard deviation in specified camera filter (nJy); omitted if no data is available;possibly nan if data is available for some objects but not others
photometric
(optional): is the object usable for photometric calibration? (a Flag)
resolved
(optional): is the object spatially resolved? (a Flag)
variable
(optional): does the object have variable brightness? (a Flag)
coord_raErr
: uncertainty incoord
along the direction of right ascension (radian, an Angle) = uncertainty in ra * cos(dec); nan if unknown
coord_decErr
: uncertainty incoord
along the direction of declination (radian, an Angle);nan if unknown
- The following are optional; fields should only be present if the information is available for at least some objects.
Numeric values are
nan
if unknown:coord_ra_coord_dec_Cov
: covariance betweencoord_ra
andcoord_dec
(rad^2)epoch
: date of observation as TAI MJD (day)pm_ra
: proper motion along the direction of right ascension (rad/year, an Angle) = dra/dt * cos(dec)pm_dec
: proper motion along the direction of declination (rad/year, and Angle)pm_raErr
: uncertainty inpm_ra
(rad/year)pm_decErr
: uncertainty inpm_dec
(rad/year)pm_ra_pm_dec_Cov
: covariance between pm_ra and pm_dec (rad^2/year^2)pm_flag
: set if proper motion, error or covariance is badparallax
: parallax (rad, an Angle)parallaxErr
: uncertainty inparallax
(rad)parallax_flag
: set if parallax value or parallaxErr is badcoord_ra_pm_ra_Cov
: covariance between coord_ra and pm_ra (rad^2/year)coord_ra_pm_dec_Cov
: covariance between coord_ra and pm_dec (rad^2/year)coord_ra_parallax_Cov
: covariance between coord_ra and parallax (rad^2)coord_dec_pm_ra_Cov
: covariance between coord_dec and pm_ra (rad^2/year)coord_dec_pm_dec_Cov
: covariance between coord_dec and pm_dec (rad^2/year)coord_dec_parallax_Cov
: covariance between coord_dec and parallax (rad^2)pm_ra_parallax_Cov
: covariance between pm_ra and parallax (rad^2/year)pm_dec_parallax_Cov
: covariance between pm_dec and parallax (rad^2/year)