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The UCAC-3

For a basic description of the UCAC-3, see the ReadMe file.

DESCRIPTION OF THE FIELDS IN THE UCAC-3 CATALOGUE:

Section 5 of the aforementioned ReadMe file has more information about the individual catalogue fields. The ASCII version of the extracted subset of the UCAC-3 catalogue contains some (or all) of the following fields:

1) id -
identification number. This number is unique for each object in the catalogue and is of the form ZZZZ-NNNNNNN. ZZZZ is the 4 digit SPD zone number that the object is in. NNNNNNN is the record number of the object in that zone file.
2) altid -
alternate identification number(s). The UCAC3 id is the official UCAC-3 object ID number, and is a unique integer that increases monotonically from the beginning of the catalogue. It is the object record number in the catalogue. A 2MASS cross-identification number is given, if there was a match. The MPOS is a unique internal to UCAC id number.
3) RA -
the Right Ascension of the object in hours or degrees. The epoch and equinox are those given in the file header. The default is equinox and epoch J2000.0.
4) DEC -
the Declination of the object in degrees. The epoch and equinox are those given in the file header. The default is equinox and epoch J2000.0.
5) sra -
the error in the RA position. This is given in integer milli-arcseconds. The error is given at the RA Mean Epoch.
6) sde -
the error in the DEC position. This is given in integer milli-arcseconds. The error is given at the DEC Mean Epoch.
7) sRaEp -
the error in the RA position at the epoch of the given catalogue position. This is given in integer milli-arcseconds.
8) sDeEp -
the error in the DEC position at the epoch of the given catalogue position. This is given in integer milli-arcseconds.
9) RA Epoch -
this is the mean epoch of all the observations that went into determining the RA position of this object. This is given in decimal years.
10) DEC Epoch -
this is the mean epoch of all the observations that went into determining the DEC position of this object. This is given in decimal years.
11) MuRa -
the proper motion in RA. This is given in angular velocity units of milli-arcseconds per year. [This equals MuRA = d(RA)/dt x cos(DEC)]
12) MuDec -
the proper motion in DEC. This is given in angular velocity units of milli-arcseconds per year.
13) sMuRA -
the error in the proper motion in RA. Given in angular velocity units of milli-arcseconds per year.
14) sMuDE -
the error in the proper motion in DEC. Given in angular velocity units of milli-arcseconds per year.
15) NFitPt -
the number of observations used in the fit for the position.
16) Flags -
this column merges many bits of information. They are indicated as individual bits in this integer. N.B: The value list in this column is given in HEXIDECIMAL.
17) NObs1 -
18) NObs2 -
19) NObs3 -
20) Vf Magnitude -
Visual magnitude. This is some sort of V magnitude, based on a PSF fit.
21) Sigma -
this gives information related to the photometric uncertainty.
22) MagFlg -
this gives information related to the photometric calibration.
23) S/G -
this field is the star/galaxy index. This is a measure of the similarity of the detection to a stellar point spread function. This is carries different information depending up on the magnitude. There is a S/G value for each individual magnitude.
24) Va Magnitude -
Visual magnitude. This is some sort of V magnitude, based on aperture photometry.
25) J Magnitude -
Near IR J magnitude. This is the J magnitude from the 2MASS survey. The valid magnitudes should span -5 to 16 magnitude. The formal valid range is 0.00 to 99.99. A value of 30.00 indicates that NO J magnitude was available for this object.
26) H Magnitude -
Near IR H magnitude. This is the H magnitude from the 2MASS survey. The valid magnitudes should span -5 to 16 magnitude. The formal valid range is 0.00 to 99.99. A value of 30.00 indicates that NO H magnitude was available for this object.
27) Ks Magnitude -
Near IR Ks magnitude. This is the K magnitude from the 2MASS survey. The valid magnitudes should span -5 to 16 magnitude. The formal valid range is 0.00 to 99.99. A value of 30.00 indicates that NO K magnitude was available for this object.
28) B -
blue magnitude. This is the magnitude derived from the POSS plates by the SuperCOSMOS project. The valid magnitudes should span ~0 to ~22 magnitude. The formal valid range is 0.00 to 99.99. This is a PHOTOGRAPHIC B magnitude.
29) R -
red magnitude. This is the magnitude derived from the POSS plates by the SuperCOSMOS project. The valid magnitudes should span ~0 to ~22 magnitude. The formal valid range is 0.00 to 99.99. This is a PHOTOGRAPHIC R magnitude.
30) I -
near IR magnitude. This is the magnitude derived from the POSS plates by the SuperCOSMOS project. The valid magnitudes should span ~0 to ~22 magnitude. The formal valid range is 0.00 to 99.99. This is a PHOTOGRAPHIC I magnitude.
31) Xi (computed quantity) -
the standard coordinate Xi, in the tangent plane projection about the requested region center. This is only computed for rectangular or circular regions. The units are decimal arcseconds.
32) Eta (computed quantity) -
the standard coordinate Eta, in the tangent plane projection about the requested region center. This is only computed for rectangular or circular regions. The units are decimal arcseconds.
33) DistCtr (computed quantity) -
distance from this object to the extraction center in arcseconds.
34) Gal_L (computed quantity) -
computed galactic longitude, in decimal degrees.
35) Gal_B (computed quantity) -
computed galactic latitude, in decimal degrees.

Comments, questions, etc., write to S. Levine
Last updated: 08dec2009 by sel