We observed GSC 1042-2191 three nights, on July 2, 6 and 10 in
2014. and three nights on July 11–13 in 2015 with the 40-cm Schmidt–
Cassegrain telescope equipped with the Apogee Alta U47 CCD camera
at Ulupinar Observatory (UPO) of Çanakkale Onsekiz Mart University
(Turkey). This camera gives image scales of 0.65 arcseconds per pixel
and provides an observed field of view (FOV) of 12 arcmin × 12 arcmin. Several bias, dark and flat frames were taken during the night
of each observation to take into account pixel-to-pixel variations on
the frame. Relevant data for eclipsing system and the adopted comparison stars are summarized in Table 1. The observational log of the
system is listed in Table 2.
The reduction of the CCD frames has been made by C-MUNIPACK
software (http://integral.sci.muni.cz/cmunipack). All frames have
been calibrated by dark frame and flat-field corrections. Differential
aperture photometry has been also performed in C-MUNIPACK. The
new observations contributed eight times of minimum light in four
filters. The minimum times determined by using the Kwee and van
Woerden (1956) method are listed in Table 3. A linear least squares
method appication to the minima times yielded the light elements ofwhich was used in phase calculation in forming the light and color
curves. The B, V, R and I light curves and the B–V, V–R and R–I color
curves are plotted in Fig. 1. The light curves in Fig. 1 show that the sec
ondary eclipse is total; i.e, the eclipsing component in the secondary
eclipse is larger and hotter component. It is clear in this case before
analysis that the system is an A-type W UMa system. The variation
of the color curves in Fig. 1. especially in B–V up to 0.1 magnitude
indicate the temperature variation on the surfaces of the larger com
ponent. Since no spot effect is observable on the light curves such
variations can be atributed to mass motions on or arround the larger
primary component.