DECH: A Software Package for Astronomical Spectral Data Processing and Analysis

—The article provides a brief description of the software package DECH for processing and analysis of astronomical spectra. DECH supports all stages of processing and analysis of spectral data, including image preprocessing, spectra extraction (including those with a variable tilted slit), wavelength calibration by a two-dimensional polynomial, continuum normalization (manual or automatic), measurement of equivalent widths and radial velocities in various ways, cross-correlation analysis, etc. The DECH software package is actively used by astronomers from different countries and continues to be improved. In particular, utilities for processing and analysis of data from the high-resolution fiber-feed echelle spectrograph installed at 6-m telescope of Special Astrophysical Observatory of Russian Academy of Sciences were added in the latest version. Software provides high-precision measurements of radial velocities, including those for detection of extraterrestrial planets.