  FRAM - F/(Ph)otometric Robotic Atmospheric Monitor is the latest addition to
the atmospheric monitoring instruments of the Pierre Auger Observatory. An
optical telescope equipped with CCD camera and photometer, it automatically
observes a set of selected standard stars and a calibrated terrestrial source.
Primarily, the wavelength dependence of the attenuation is derived and the
comparison between its vertical values (for stars) and horizontal values (for
the terrestrial source) is made. Further, the integral vertical aerosol optical
depth can be obtained. A secondary program of the instrument, the detection of
optical counterparts of gamma-ray bursts, has already proven successful. The
hardware setup, software system, data taking procedures, and first analysis
results are described in this paper.

Astrophysics