Catalog Manipulation

  Although the observing command ants can be used to point at a given RA/DEC or AZ/EL, the source= and catalog= keywords control the source to be observed. Catalogs can be present in the current directory (not a good idea during observing), the standard directory $HATCAT, or in a public area $UCAT. If for some reason you cannot find your source in any of the available catalogs, you need to make a new catalog, or append it to an existing one. First, the command to list the contents of an existing catalog:

    % cd /tmp
    % catalog catalog=$UCAT/lgm.cat log=lgm.log initials=lgm
    % cat lgm.log
Source     RA (2000)    PMra(s)    DEC (2000)   PMdec(")    Veloc      Date  
N1333I4  03:28:11.100  (  0.000) 31:13:23.510  (  0.000)      4.0 km/s    0.0
N1333I2A 03:28:56.290  (  0.000) 31:14:34.040  (  0.000)      7.0 km/s 2000.0
N1333I2B 03:29:00.960  (  0.000) 31:14:20.000  (  0.000)      7.0 km/s 2000.0
...

or

    % catlog $UCAT/lgm.cat 
N1333I4  03:28:11.100  (  0.000) 31:13:23.510  (  0.000)      4.0 km/s    0.0
N1333I2A 03:28:56.290  (  0.000) 31:14:34.040  (  0.000)      7.0 km/s 2000.0
N1333I2B 03:29:00.960  (  0.000) 31:14:20.000  (  0.000)      7.0 km/s 2000.0
...

if you use the catlog  script in checker.

Although you can make new catalogs in checker, it probably makes more sense to make them at the site, or else you can copy them (ftp in binary mode!) to the site afterwards, much like your observing script. Here is how to append (or create) a new catalog:

    % catalog catalog=$UCAT/lgm.cat initials=pjt
CATALOG (version 1.2 30-jul-93)
 Enter/Manipulate a catalog entry:
        At each prompt, you may type:
                <RETURN>        use current value
                delete          Delete the source
                abort           Abort work on this source
                list            List the catalog
                CTRL/D          EXIT from loop
SOURCE Name (char*8) [  ]                        < test1
Right Ascension(J2000)(h:m:s) [00:00:00.000  ]   < 12:11:10
PM for RA (sec per year) [     0.000]            < 0.0
Declination(J2000)(d:m:s) [00:00:00.000  ]       < 30:12:10
PM for DEC (" per year) [     0.000]             < 0.0
LSR Velocity (km/sec) [     0.000]               < 45.3
Observed EPOCH (year) [     0.000]               < 1995.2
COMMENTS [                        ]              < testing
 Enter/Manipulate a catalog entry:
        At each prompt, you may type:
                <RETURN>        use current value
                delete          Delete the source
                abort           Abort work on this source
                list            List the catalog
                CTRL/D          EXIT from loop
SOURCE Name (char*8) [  ]                        < ^D

Note that the coordinates must be in J2000 while the observing year can optionally be given to obtain second order corrections for more accurately derived coordinates during observing. For example, for a VLBI source you probably would want to give a non-zero observing year, since it will predict the RA/DEC for any other time with higher accuracy.

Examples of use of the MIRIAD programs j2000  and cotra  are:

    % j2000 ra=03:28:11.100  dec=31:13:23.510 
    J2000: version 23JUL97
    Ra2000: 3:31:17.056      Dec2000: 31:23:34.355

    % cotra radec=03:28:11.100,31:13:23.510 
    COTRA: Version 1.0 07-Aug-97
    J2000:            3:31:17.055    31:23:34.46
    B1950:            3:28:11.100    31:13:23.51
    Galactic:          158.668999    -20.167891
    Ecliptic:           57.478347     11.963307
    Super-Galactic:    158.668999    -20.167891