Summary of ASU qualifications for VizieR

The generic URL used in ASU follows the generic rules of the HTTP protocol (RFC 1945):

where the ampersand &) separates the arguments when there is more than a single argument. The HTTP protocol also specifies that any special character (blank, quotes, and + * < > & # ) exsiting in an argument should be encoded by a percent sign (%) followed by its ascii hexadecimal representation. The blank must therefore be replaced by %20, the + sign by %2b, etc.

The root URL to get results from VizieR is

In the root URL, the host name ( may be replaced by one of the mirrors:,,,,,,,

Following the question mark (?), the ASU arguments are written in the general form name=value The following conventions about name are used:

Specifying a Choice of Catalogues:   there are several ways of designating catalogues; the fastest is to use the catalog identification assigned in VizieR like -source=I/239/hip_main for the main Hipparcos catalog.

||-source=	 ||catalog(s) to query 
	(Several catalogs may be specified if separated by
	a comma or a blank). 
Well-known catalog abbreviations may be used – the full list of abbreviations known in VizieR can be listed.|| ||-words= ||names or words of title of catalog. The words are and'ed, i.e. only the catalogues characterized by all the words are selected.|| ||-kw= ||keyword in any of the 3 lists by Wavelength, Mission, or Astronomy.
If several keywords are given on the line, they are or'ed; but if several lines with -kw=value exist, their content is and'ed.|| ||-ucd= ||designation of UCD
The catalogues having one or more columns matching the specified UCD(s) are selected; the * may be used as a wild character, e.g. PHOT_*_B represents a blue photometry which can be in a lot of different photometric systems.
Several -ucd=value can be used to select catalogues having simulteously the properties specified by the UCDs; in other terms, similalry to -kw, UCDs specified on the same line are or'ed, while the different lines are and'ed.|| ||-pos ||restricts to tables containing celestial positions|| ||-phot ||restricts to tables containing well-defined photometry|| ||-nosurvey ||restricts the choice to catalogues outside the ``survey'' list of catalogues.|| ||-obsolete ||asks to include the obsoleted versions of catalogues in the set.|| ||-corr= ||correlation for a fine-grain selection of tables:
	-corr=pos  restricts to tables having a position;
	-corr=name=col_name  restricts to tables
	      	having the specified col_name among its columns;
	-corr=PK=col_name   restricts to tables
	    	having the specified col_name and this column
		is a primary key of the table;
	-corr=FK=col_name   restricts to tables
	    	having the specified col_name and this column
		is a foreign key of the table;

Target Center:   the specification of a target requires a center – a position in the sky – and a geometry around the center. Only a circle/annulus, and a rectangular box, are available.

||-c=	 ||defines the center of the target 
There are many possibilities of specifying the center – by object name, position in sexagesimal or decimal degrees. For equatorial positions, remember that a sign must exist before the declination, and that no decimal point in the RA part implies a sexagesimal position (i.e. 15 +12 means 15h+12°, but 15.+12 means 15°+12°, or 1h+12°.|| ||-c.eq= ||defines the equinox of the position given in the -c argument. Note that this parameter is not useful when the target is specified by a name.
Typical examples are -c.eq=B1950 or -c.eq=Gal
The default is -c.eq=J2000|| ||-c.rm= ||defines the radius of the target in arcminutes.
Two numbers may be specified: in the case, the target is an annulus.|| ||-c.rd= ||defines the radius of the target in degrees.|| || ||defines the radius of the target in arcsec.|| || ||defines a rectangular box of horizontal/vertical dimensions in arcmin, as e.g.|| || ||defines a rectangular box in degrees|| || ||defines a rectangular box in arcsec.|| ||-box= ||defines a rectangular box using IAU-conventions, e.g. J0000-00 for a box in J2000 coordinates containing the positions having their RA between 0h0m and 0h1m and their declination between and –1° This convention is valid also with other coordinate systems: Bhhmm...±dd... (B1950 position), Glon...±lat... (galactic position), S... (supergalactic) and E (ecliptic).
Finally a box may also be represented by a qbox value, the systems of cells used to access by positions (described briefly in the qbox man page)||

Output Contents:   the contents and order of the result can be specified by the following arguments:

||-meta	 ||No actual query is performed, only the tables
		involved in the query are described. This is
		useful to get an idea of which catalogues
		exist which share e.g. a keyword. ||
||-meta.all	 ||similar to -meta, but all metadata 
		(details of columns) are listed.||
||-meta.max=	 ||specifies the maximal number of catalogs to be listed
	(the default is 500) ||
||-out=	 ||specifies the result columns to list in the output;
	-out= is normally followed by a list of column names
	(separated by blanks)
	to be displayed. 
The list may contain, in addition to standard column names: || ||-out.all ||Display all columns (i.e. -out.all is equivalent to -out=**)|| ||-out.add= ||List of columns to add to the standard set, e.g. -out.add=_r lists the distance to the target || ||-out.max= ||Maximal number of rows to retrieve (default is 50)|| ||-out.meta= ||Some options on the descriptions of the columns, as a set of characters referring to the possible additional details; the list may be preceded by + or - for addition or removal of the following elements:
	||h  ||(header) add the column names ||
	||u  ||(unit) add the units of each column ||
	||U  ||(UCD1) give the UCD1 (default is UCD1+)||
	||2  ||(2UCDs) give the two UCDs (UCD1 and UCD1+)||
	||D  ||(Description) adds the description of columns ||
	||L  ||(Links) add the definition of Links 
		(may result in more columns than what was asked)||

The default is huD; to get for instance the 2 UCDs, add   -out.meta=+2|| ||-out.form= ||Some options on the output:
	||DTD  ||(for VOTable output): use the DTD definition rather than
		the standard XML-Schema ||
	||bin64  ||(for VOTable output): use a binary 64-encoded output
		for the data ||
	||TSV  ||(for VOTable output): use a Tab-Separated-Values
		representation of the data 
		(the Astrores way) ||
	||groups  ||(for VOTable output): use the groups of
		columns introduced in VOTable1.1||
	||mini  ||(for lists): minimize the output, i.e. keep a
		single table which gathers the results of the list
		(the list must be applied to a single table) ||
|| ||-sort= ||Sort order, e.g. -sort=_r to sort by increasing distance to the target. A minus sign before the column name (e.g. -sort=-_r) indicates a decreasing order.|| ||-oc.form ||form of the computed position, as -oc.form=d for decimal degrees, or-oc.form=s for sexagesimal representations. An optional M (Main) can be added to specify that the UCD qualification main main is added to the computed position (by default this main qualification is attached to the original position) ||

Joining tables:   Two or more tables can be combined or joined into a single table; some details and examples can be found in the join documentation. The following argments are specific to joins:

||-joincol 	 ||specifies the column used in the join (the name must be
		shared among the tables involved).||
||-outjoin	 ||specifies the table.column of the referent column
		in the case of outer joins.||

Issuing several queries:   Independant queries can be issued in a single request, using a -go separator. More control can be specified in the case of votable output:

2012-12-12 — François Ochsenbein () <&CDS.headStuff2><&CDS.tailArea2 "/home/cds/httpd/vizier/doc/asu-summary.htx" "" "">