Worked example

This section gives a complete worked example of producing a customised finding chart. It starts be searching a remote on-line catalogue with catremote (see Section ) to find the list of objects which will produce the chart. The finding chart will show objects in the USNO PMM catalogue[20] within 5 minutes of arc of the radio source PKS 1417-19. Proceed as follows.

1. You need to know the coordinates of the central object for epoch and equinox J2000. You may already know them, or it might be convenient to look them up in a paper catalogue or on-line using SIMBAD. Alternatively, it is easy to obtain them using catremote, type:

   catremote name  simbad_ns@eso  pks1417-19

   The object name is entered without spaces and may be in either case (upper or lower). catremote will return the coordinates of the object for epoch and equinox J2000:

   Right Ascension: +14:19:50
   Declination: -19:28:21

   The Right Ascension is in sexagesimal hours and the Declination in sexagesimal degrees. If you know the coordinates for some equinox other than J2000 then you can use the Starlink utility COCO (see SUN/56[31]) to convert them to the required equinox.

2. To search the USNO PMM catalogue[20] for objects within 5 minutes of arc of this position type:

   catremote query usno@eso  14:19:50  -19:28:21  5

   catremote will respond:

   !(Info.) Catalogue usno_eso_141950_m192821.tab written successfully.

   and the target list of selected objects will be written to file usno_eso_141950_m192821.tab in your current directory.

3. The target list can be customised for plotting using the graphics translation file supplied for the USNO PMM (see Table ). Type:

   catchartrn

   and answer the prompts (the prompts are shown on the left and replies on the right):

   GTFILE - Graphics translation file:	/star/share/cursa/usno.grt
   CATIN - Input target list:	usno_eso_141950_m192821.tab
   CATOUT - Output graphics attribute list:	usno_plot.txt

   The customised target list will be written to file usno_plot.txt.

4. To plot a finding chart from the customised target list type:

   catchart  title=\'PKS 1417-19\'

   Note that the title must be enclosed in quotes and the quotes preceded by a backslash (as shown) to prevent them being interpreted by the Unix shell. Answer the prompts as follows (again prompts to the left, replies to the right):

   GRPHDV - Graphics device:	ps_l
   GRPLST - Target list:	usno_plot.txt

   The position of PKS 1417-19 will be marked by an open cross. Here the finding chart has been written as a postscript file, called gks74.ps, which may be printed, displayed interactively etc, as desired.