file extension RV

SPEFO

SPEFO is a small, yet powerful program used for processing stellar spectra at the Astronomical Institute of the Academy of Sciences of the Czech Republic in Ondrejov. It was originally written in 1990 by Dr. Jirí Horn for processing spectral plates obtained with the 2m telescope of the Ondrejov observatory and scanned with the local five channel microphotometer. Since then the code had been under constant improvement until the sudden death of the author in December 1994. Currently SPEFO is used mainly for the reduction of data from the Ondrejov Reticon detector (1872 pixels, 12 bit A/D), however it can process data from other instruments too, provided that they are in FITS one-dimensional format.

The code was written in Turbo Pascal for MS-DOS; the size of the binaries is less than 350 KB. SPEFO will run on an ordinary PC computer with very modest hardware demands (PC AT 286, 1 MB RAM, 30 MB HD color EGA or VGA). Despite its small size the program is very powerful, and user friendly as well. The basic data reduction tasks such as derivation of the dispersion function, spectrum rectification, Fourier noise filtering, radial velocity and equivalent width measurements are performed in an easy manner, and the user can immediately see changes to the data on a screen plot (e.g., the line position is determined in the ``oscilloscopic'' mode by finding the coincidence of the displayed line and its interactively shifted mirrored profile, the continuum level spline is recalculated after fixing each new point, etc.).

The main output of SPEFO is a table of radial velocities of measured stellar lines (including the atmospheric line correction), their equivalent widths and higher order moments, relative central line intensities and FWHM, together with the HPGL plot file. The program can do basic operations on spectra like comparison of two spectra, subtraction, adding, production of differential spectra or the transformation by rotational broadening. SPEFO can also deal with synthetic spectra produced from various model stellar atmospheres allowing their comparison with real data and hence determining the physical parameters (, chemical composition) of the star under investigation.