Related papers: Optical Multicolor Observations of the SS 433=V 13…

We report BVR photometry of the V1343 Aql= SS 433 microquasar at different phases of the 13--day orbital cycle for the 1986--1990 observing seasons. The data include five complete cycles of the 163$^{d}$ precession period of the system. We…

We report the results of WBVR photometry of the massive close x-ray binary V1341 Cyg=Cyg X-2 in 1986-1992. In the "off" state the amplitudes of the periodic component of light variations lie in the $0^{m}.265 - 0^{m}.278$ and $0^{m}.290 -…

\rm Observations of close binary system (CBS) V1357 Cyg=Cyg X-1 in the $WBVR$ bands are reported. Photometry was carried out at the telescopes located in Kazakhstan, Uzbekistan and Crimea equipped with single-channel $WBVR$-photometer with…

The detection of two sources of gamma rays towards the microquasar SS 433 has been recently reported. The first source can be associated with SS 433's eastern jet lobe, whereas the second source is variable and displays significant…

The unique microquasar SS433 is a massive X-ray binary system at an advanced evolutionary stage. The optical star overflows its Roche lobe and transfers mass at a very high rate onto a black hole surrounded by a supercritical accretion disk…

We present a study of the mass transfer and wind outflows of SS433, focusing on the so-called stationary lines based on archival high and low resolution optical spectra, and new optical multifilter polarimetry and low resolution optical…

We present results of four-color WBVR- photoelectric observations of the close binary HZ~Her=HER~X-1 in 1986--1988. As a rule, the duration of the observations exceeded two 35-day X-ray orbital periods in the 1986--1988 observing seasons.…

We report four-color WBVR photoelectric photometry of the close binary system (CBS) HZ HER/HER X-1 made in 1986-1994. Our photometry usually covered at least two 35d precession periods during each of the 1986-1990, 1992, and 1994 observing…

Results of simultaneous INTEGRAL and optical observations of galactic microquasar SS433 in May 2003 and INTEGRAL/RXTE observations in March 2004 are presented. Persistent precessional variability with a maximum to minimum uneclipsed hard…

Based on multiyear INTEGRAL observations of SS433 in 2003-2011, a composite IBIS/ISGRI 18-60 keV orbital light curve is constructed around zero precessional phases psi_{pr}= 0 at the maximim accretion disk opening angle. It shows a peculiar…

New Multi-color $B$ $V$ $R_c$ $I_c$ photometric observation are presented for W UMa type eclipsing binary V1073 Cyg. The multi-color light curves analysis with the Wilson-Devinney(W-D) procedure acquired the absolute parameters of this…

We present the results of $WBVR$ observations of the low-mass X-ray binary V1341 $\textrm{Cyg} = \textrm{Cyg}$ X--2. Our observations include a total of 2375 individual measurements in four bands on 478 nights in 1986-1992. We tied the…

We present the first optical observation at sub-milliarcsecond (mas) scale of the microquasar SS 433 obtained with the GRAVITY instrument on the VLT interferometer. The 3.5 hour exposure reveals a rich K-band spectrum dominated by hydrogen…

Results of simultaneous {\it INTEGRAL} and optical observations of galactic microquasar SS433 in May 2003 are presented. The analysis of the X-ray and optical eclipse duration and hard X-ray spectra obtained by {\it INTEGRAL} together with…

We present the results of the optical monitoring of 18 southern blazars in the V and R Johnson-Cousins bands. Our main objective is to study the variations in the optical flux and theis relationship with the colour and spectral…

We present a long term optical $R$ band light curve analysis of the gravitationally lensed blazar AO 0235+164 in the time span 1982 - 2019. Several methods of analysis lead to the result that there is a periodicity of ~8.13 years present in…

We continuously monitored the blazar S5 0716+714 in the optical $g$, $r$ and $i$ bands from Nov. 10, 2017 to Jun. 06, 2019. The total number of observations is 201 nights including 26973 data points. This is a very large quasi-simultaneous…

V383Sco was discovered to be an eclipsing binary at the beginning of the XX century. This system has one of the longest orbital periods known (13.5yr) and was initially classified as a zet_Aur-type variable. It was then forgotten for…

A recent optical monitoring campaign on the prominent quasar 3C279 revealed a period of a remarkably clean exponential decay of BVRI fluxes with time, with a time constant of 12.8 d, over about 14 days. This is clearly too long to be…

We have studied the long-term (~ years) temporal variability of the prototype supersoft X-ray source (SSS) CAL 83 in the LMC, using data from the MACHO and OGLE projects. The CAL 83 light curve exhibits dramatic brightness changes of ~1 mag…