Format of the VTD a priori file of proper motions and parallaxes.

Last update: 2023.03.14

A file with the VTD a priori file of proper motions and parallaxes
consists of lines of variable length in ascii format. The first
line, so-called UNIX magic, identifies the format name and revision:

# Source proper motion and parallax. File format  1.0  of 2023.03.11

  Lines with # in the first position, except the first line, 
are considered as comments and are discarded by the parser. Empty
lines are allowed. They are discarded buy the parser.

  A data record consists of 6 fields separated by a blank (decimal code 32)
and/or exclamation sign.

  Field  Format  Meaning

   1-8    A8     IVS source name that usually follows B-name IAU convention

  11-20   A10    J-name  IAU source name

  23-32   F10.4  Proper motion in right ascension in mas/yr. The proper motion
                 is not scaled by 1/cos(declination)

  35-44   F10.4  Proper motion in declination in mas 

  47-54   F8.4   Parallax in mas

  56-56   A1     Delimiter

  58-121  A64    Comment
