PHOTOMETRY OF STARS FOR ASTRONEGATIVES WITH A SINGLE EXPOSURE

Анотація

The paper discusses the construction of
characteristic curves for various astronegatives with a
single exposure. Particular attention is paid to the question
of extrapolation of the characteristic curve for the region
of the weakest stars in the absence of standards. A new
method for constructing an individual characteristic curve
for digitized films and plates in the UBVR system has
been proposed and implemented. The processing of
frames of digitized plates and films with sky areas is car-
ried out using LINUX/MIDAS/ROMAFOT software
tools. ROMAFOT application allows us to extract astro-
metric rectangular coordinates X,Y and photometric char-
acteristics such as instrumental photometric magnitudes
m, FWHM, and the intensity in the center of the star im-
age I c for all fixed objects on each astronegative. For all
frames, the connection between instrumental photometric
values m with stellar magnitudes in any system (Johnson
UBVR, Tycho-2 or GAIA catalogs, etc.) is not linear and
multipurpose. It is presented as the characteristic curve for
each astronegative. Currently, the determination of U, B,
V, R magnitudes of stars and other space objects is in pro-
gress for astronegatives with the single exposure obtained
in the frameworks of selected observational projects.