How to make an image in PGPLOT with correctly labelled RA/Dec box labels

The goal here is to make a publication quality image of the sky with the coordinates labelled in the standard Right Accession/Declination units. As this is not entirely trivial, here are some notes to help:

• Use the PGTBOX function which knows how to label the coordinate box in time units

• The options to the RA (normally horizontal) axis should include:

  • òÀÜZòÀÝ to turn on time labelling
  • òÀÜYòÀÝ to remove the day field (if it was something different to zero than you are probably doing something wrong)
  • òÀÜHòÀÝ To superscript with h/m/s

• The options to the Dec (normally vertical) axis should include:

  • òÀÜZòÀÝ for time labelling
  • òÀÜDòÀÝ for degree, arc-minute, arc-second symbol labelling

• I additionally also include:

  • òÀÜBCòÀÝ to draw the box
  • òÀÜINTòÀÝ To draw tick marks and label them (òÀÜIòÀÝ so that the ticks are inverted, i.e., going outside the box)

• The coordinate system for Right Accession axis should be in seconds of time (240 seconds/degree). The coordinate system for Declination axis should be in seconds of arc (3600 seconds/degree).

• When calling PGSWIN remember that the RA axis is decreasing! So the first element should be larger than the second in call the PGSWIN (assuming RA is the horizontal axis)

• Ensure that the matrix representing the coordinate system of the image is correct when calling PGIMAG