A VAX catalog consists of two parts: a header with general information and the source part with one line per source (containing source name, coordinates and - if necessary - velocity information).

Keywords are:

• SBAS: Basis system of the catalog - see below
• SNAM: source name
• SLAM: longitude of the source (in the coordinate system defined by SBAS)
• SBET: latitude of the source (in the coordinate system defined by SBAS)
• VLSR: velocity against the local standard of rest
• VHEL: velocity against the heliocentric movement
• VBAR: velocity against the barycentric movement

The following basis systems are possible:

Example catalog:

COMMON: SBAS= -1
INDIVIDUAL: SNAM SLAM SBET VLSR
! that's the header
! SBAS = -1 -> coordinates are equatorial, J2000.0
!
! comments can be included with an exclamation mark
! now comes the source part
!
SNAM=W3OH           ; SLAM=02 27 03.9   s; SBET= 61 52 24.0 "; VLSR=-44
SNAM=ORION-S        ; SLAM=05 35 13.440 s; SBET=-05 24 08.10 "; VLSR=7
! and so on, and so forth...