Related papers: A Note on the Variability of V538 Cassiopeiae

A detailed analysis of more than 800 electronic high-resolution spectra of gamma Cas, which were obtained during a time interval of over 6000 days (16.84 yrs) at several observatories, documents the smooth variations in the density and/or…

The Central Compact Object (CCO) in the Cassiopeia A supernova remnant is most likely a very young ($\approx 300$ yr) neutron star. If a previously reported decrease of its surface temperature by 4% in 10 years could be confirmed, it would…

As part of a project to better characterize comparatively bright, yet little studied cataclysmic variables time resolved photometry of the three eclipsing novalike variables EC 21178-5417, GS Pav und V345 Pav is presented. Previously known…

In this paper results from the optical photometric observations of the pre-main-sequence star V1180 Cas are reported. The star is a young variable associated with the dark cloud Lynds 1340, located at a distance of 600 pc from the Sun in…

We present results from a season of observations with the Chinese Small Telescope ARray (CSTAR), obtained over 183 days of the 2010 Antarctic winter. We carried out high-cadence time-series aperture photometry of 20,000 stars with i<15.3…

We present our observational results of AM CVn star CR Boo in the UBVR bands. Our observational campaign includes data obtained over 5 nights with the National Astronomical Observatory Rozhen, Belogradchik and the AS Vidojevica telescopes.…

We monitored BL Lacertae simultaneously in the optical B, V, R and I bands for 13 nights during the period 2012-2016. The variations were well correlated in all bands and the source showed significant intraday variability (IDV). We also…

All available CCD observation of RV UMa have been analyzed to obtain an accurate mathematical description of the ligh variation. We discuss in this paper a new study of variable star RV UMa, a short period RRab star, in orther to determine…

ASTEP South is an Antarctic Search for Transiting Exo- Planets in the South pole field, from the Concordia station, Dome C, Antarctica. The instrument consists of a thermalized 10 cm refractor observing a fixed 3.88\degree x 3.88\degree…

We report results of VI time series photometry for the bright globular cluster M5 taken between 2007-2011 using the 0.5-m telescope at Bowling Green State Univ. and the PROMPT #4 telescope at Cerro Tololo. We used DAOPHOT to obtain…

We explore the dominant modes of variability in the observed albedo at the cloud tops of Venus using the Akatsuki UVI 283-nm and 365-nm observations, which are sensitive to SO2 and unknown UV absorber distributions respectively, over the…

We present the results of the short-term constancy monitoring of candidate Gaia Spectrophotometric Standard Stars (SPSS). We obtained time series of typically 1.24 hour - with sampling periods from 1-3 min to a few hours, depending on the…

We present observations (with NAO Rozhen and AS Vidojevica telescopes) of the AM Canum Venaticorum (AM CVn) type binary star CR Bootis (CR Boo) in the UBV bands. The data were obtained in two nights in July 2019, when the V band brightness…

We use differential CCD photometry to search for variability in BVI among 990 stars projected in and around the old open cluster M 67. In a previous paper we reported results for 22 cluster members that are optical counterparts to X-ray…

We present the photometric properties of V608 Cas from detailed studies of light curves and eclipse timings. The light curve synthesis indicates that the eclipsing pair is an overcontact binary with parameters of $\Delta T$ = 155 K, $q$ =…

Recently, brightness variations occurring on twice the accretion disk precession period in the old nova and permanent superhump system V603 Aql have been observed by Bruch & Cook (2018). In an attempt to detect a similar effect in other…

Here we present the first optical photometric monitoring results of a sample of twelve newly discovered blazars from the ICRF - Gaia CRF astrometric link. The observations were performed from April 2013 until August 2019 using eight…

We report the flux and spectral variability of PG 1553+113 on intra-night (IDV) to short-term timescales using BVRI data collected over 91 nights from 28 February to 8 November 2019 employing ten optical telescopes: three in Bulgaria, two…

Using the Harvard College Observatory Photographic Plate Collection and recent CCD observations by the ASAS project we have reconstructed the light variations of the southern pulsating red giant star VZ Velorum between 1890 and early 2006.…

We have obtained mosaic images of NGC 3109 in the V and I bands on 74 nights, spanning approximately one year. From these data, we have conducted an extensive search for Cepheid variables over the entire field of the galaxy, resulting in…