Getting started & organizing files

Starting a PyRAF session

  • In red/, start a PyRAF session and an image display tool, eg.:

    > ds9 &
    > pyraf
  • A provided file automatically defines raw$ & scripts$ path variables, picks up the local LA Cosmic and configures image display for GMOS.

  • Subsequent commands may be pasted into your PyRAF session and/or a CL script in a text editor (a complete script is provided for reference in scripts/ref/ When constructing a CL script or working in CL (rather than PyRAF), you must remove the iraf. prefix from any parameter settings (eg. below).

  • Load all the packages needed by the reduction process:

    task gmosaic=home$../scripts/   # gap interpolation patched
    unlearn gemtools gmos                     # use reproducible parameter defaults
    • You can add these commands to if you want (along with gdisplay.fl_paste below), so you don’t have to repeat them when restarting your session. If pyraf fails to start as a result, you may need to comment out the section in your beginning if (deftask("samp") == yes) {.
  • Specify a log file for this target (optional) and display GMOS images using the more practical fl_paste+ option:


    Again, remove the iraf. here when pasting into a script.

  • I believe the previous GMOS tutorial by Ricardo will discuss what GMOS data look like in general (otherwise I can elaborate a bit on that before moving on).

Organizing the data

  • Organize the data files into lists. Some (not all) reduction steps can use these to construct their input or output filenames, avoiding more repetition than necessary in our script.

    gemlist S20140919S 90-94 > slow_bias.lis
    gemlist S20140926S 178-182 > fast_bias.lis
    gemlist S20140919S 60-61 > flat.lis
    gemlist S20140919S 80-81 > arc.lis
    gemlist S20140919S 59,62 > std.lis
    concatenate flat.lis,arc.lis,std.lis all.lis