During the night while observing, observers may do as much of the data reductions as desired. This will be especially useful when more than one observer is present, as there are two computer terminals. This can reduce considerably the effort needed in subsequent reductions downtown or at the observers home institution. At the very least, calibrations frames can be averaged, images bias subtracted and trimmed, and flat fielding done. Various manuals exist for descriptions of the steps involved, a few of which are listed here:
User's Guide to the CCDRED Package, by Francisco Valdes (Available via anonymous ftp to "ftp://iraf.noao.edu/iraf/docs/", get ccdguide.ps.z);
User's Guide to CCD Reductions with IRAF, by Philip Massey (Ftp address as above, get ccduser2.ps.z);
User's Guide to Reducing Slit Spectra with IRAF, by Massey, et al (Ftp address as above, get spect.ps.z);
Guide to the Slit Spectra Reduction Task DOECSLIT, by Francisco Valdes (Ftp address as above, get doslit2.ps.z);
User's Guide to Reducing Echelle Spectra With IRAF, by Daryl Willmarth and Jeannette Barnes (Ftp address as above, get ech.ps.z).