Change over to your PTI data directory:
$ cd /mnt/hgfs/D/projects_aux/ptidata/
Pick a year - say, 2001- and cd over there:
$ cd 101
In this subdirectory, you'll see lots of files with names like "101153.*". The leading 3 digits are the year number, followed by 3 digits of day-of-year-number.

Now, let's go down one further level in the 'ps' directory:
$ cd ps
This directory is full of Postscript files that display the data for each given night.
To look at one of these files:
$ gv
Look for the 'Incoherent Spec V2' page - usually page 4 or 5 - for a display of a given night's data.