GNUPLOT is a command-driven interactive function plotting program. It is very convenient for having a quick look at the behaviour of various mathematical functions. Most commands are explained in the online help (type 'help'!) which has similar characteristics as the VMS online help. GNUPLOT offers several output possibilities as postscript, encapsulated postscript, or LaTeX. The latter is quite useful since it permits to refine plots up to e.g. publication quality using all facilities prvided by LaTeX. The sub-routines GNUFIT have been linked to the present version on the DEC-alphas. This implementation incorporates the capability of nonlinear least squares fit by using the Marquardt-Levenberg-Algorithm. At I.R.A. GNUPLOT is installed on the DEC-alpha Work-Stations (Version 3.5) and also on the LINUX computers (Version ). To start the program enter: gnuplot To see the manual pages enter: man gnuplot The GNUPLOT User's Manual is available in two different forms: Postscript files at the web address: http://www.ira.inaf.it/ira-docs/calcolo.html Manuals in room 307 Contact Person: K.H.Mack mack@ira.inaf.it F.Tinarelli tinarelli@ira.inaf.it