Information on Service 'PPMXL Catalog Cone Search'

For a list of all services and tables belonging to this service's resource, see Information on resource 'ppmxl/q'

Service Documentation

To query this data, you can use

• a web form (mainly for cone searches)
• the equivalent SCS service using your favourite VO client (e.g., topcat)
• our web-based crossmatcher to retrieve PPMXL data (e.g., proper motions and photometry) for your object list
• web-based ADQL or, preferentially,
• TAP for more advanced queries.

You can retrieve also the whole data set as a gzipped text file from http://vo.ari.uni-heidelberg.de/ppmxl (39.4 GiB). The columns in the text file are in database order as documented in the table info in DB order with columns separated by vertical bars ("|").

David Tholen kindly provided code to convert this into a collection of files for easy consumption by FORTRAN programs.

Overview

You can access this service using:

• form -- an interface for web browsers through an HTML form
• scs.xml -- a standard SCS interface as defined by the IVOA to access catalog-type data; SCS clients use http://data.xao.ac.cn/ppmxl/q/cone/scs.xml? to access the service

VOResource XML (that's something exclusively for VO nerds)

Note 1

Magnitudes from USNO-B should be used with care. Photometric calibration may be severely off for some plates.

For objects from PPMX (bit 1 set in flags), these magnitudes have a special meaning as per the following table:

PPMXL column	PPMX column	PPMX content
b1mag	Cmag	Catalogue magnitude from source
b2mag	Bmag	Johnson B magnitude
r1mag	Rmag	calc. Ru magnitude from source
r2mag	N/A	always None
imag	Vmag	Johnson V magnitude

Note 2

magSurveys is built by concatenating the digits assigned to the surveys for b1mag, b2mag, r1mag, r2mag, and imag (in this sequence). The digits are those of given in Note h to Table 3 in 2003AJ....125..984M, except we do not distinguish POSS-II N and SERC-I as a part of POSS-I-N (i.e., both 7 and 9 are 7 here).

From this field, you can also see which of the surveys contributing to USNO-B had positions for the object.

Note 3

The flags column contains a bitwise or of warnings and similar conditions. The bit's meaning is as follows:

bit 0:	If set, one of the coordinates had an excessively large chisquare.
bit 1:	Row is from PPMX. These objects are mostly Tycho stars that were masked out of USNO-B. For these, the USNO magnitudes (b1mag through imag) have special meanings. See the note on magnitudes.
bit 2:	Row is from PPMX and replaces a single row from USNO-B. This is done when the astrometry from PPMX was better (in terms of error estimates) than the astrometry of the corresponding PPMXL object.
bit 3:	Row replaces multiple USNO-B1.0 objects. When PPMX contains an object that has more than one counterpart in PPMX-L, all such counterparts are discarded on the assumption that they should have been matched in USNO-B1.0 or result from erroneous matches. For these rows, bit 1 is always 1.

Note 4

nobs may be NULL for stars coming from ARIHIP or Tycho-2 via PPMX (i.e., bit 1 is set in flags).