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Positional and multicolor photometric observations of near-Earth asteroids were carried out using the SBG telescope of the Kourovka Astronomical Observatory of Ural Federal University and the Zeiss-1000 telescope of the Simeiz Observatory of INASAN in 2022–2023. Based on the results of positional observations with the SBG telescope, improved orbital elements were obtained for seven asteroids. The periods of axial rotation of seven asteroids were estimated from photometric observations. Based on the results of photometric observations in the B, V, R, I filters, color indices were obtained for six asteroids. [ABSTRACT FROM AUTHOR]

The paper is dedicated to the memory and scientific heritage of Mariy Anatolyevich Svechnikov, an outstanding researcher and teacher, founder of the Ural school of study of close binary systems and author of the classification of eclipsing variable stars. The paper provides a brief overview of the major life events and main scientific achievements of M.A. Svechnikov. The best memory is the continuation and development of those scientific directions to which he devoted his scientific activity. The research initiated by M.A. Svechnikov was continued in the works of his apprentices and followers at the Ural State University, Chelyabinsk State University, Chita State University, etc. The paper is based on a talk presented at the astrophysical memorial seminar "Novelties in Understanding the Evolution of Binary Stars," dedicated to the 90th anniversary of Professor M.A. Svechnikov. [ABSTRACT FROM AUTHOR]

We present the results of our analysis of multiwavelength observations for the long gamma-ray burst GRB 200829A. The burst redshift has been determined photometrically at the afterglow phase. In gamma rays the event is one of the brightest (in isotropic equivalent), erg. The multicolor light curve of the GRB 200829A afterglow is characterized by chromatic behavior and the presence of a plateau gradually transitioning into a power-law decay that can also be interpreted as a quasi-synchronous inhomogeneity (flare). We assume that the presence of a chromatic inhomogeneity in the early afterglow is consistent with the model of a structured jet. [ABSTRACT FROM AUTHOR]

This paper studies about the 130-cm Devasthal Fast Optical Telescope (DFOT) at Devasthal, India that has been in operation for more than 10 years and is the main workhorse for the photometric observations for a wide range of scientific programs carried out at ARIES, Nainital. Having a 2 k × 2 k pixel imager mounted on the prime focus of the telescope, DFOT provides a field of view of about 1 8 × 1 8 arcmin2 in the sky. Another frame transfer CCD imager of 5 1 2 × 5 1 2 pixel size enables monitoring transient sources with millisecond temporal resolution. DFOT is equipped with a filter assembly having eight filters, an auto-guider, an All Sky Camera, and GPS-enabled weather monitoring system to support the observations in the most optimum way. The telescope is capable of producing sub-milimag photometric stability which has allowed us to detect many small-scale photometric variations. [ABSTRACT FROM AUTHOR]

The results are presented of a numerical simulation for the motion of a group of geosynchronous objects from positional observations obtained with the unique Zeiss-2000 research facility at the Terskol Observatory, Institute of Astronomy, Russian Academy of Sciences. A description is given of improved high-precision mathematical software designed to work with positional observations of satellites. The results are discussed of testing the software for observations of near-Earth objects obtained with the above-mentioned Zeiss-2000 facility. The modified software helps determine the dynamic state vector of a near-Earth object and its windage parameter. The testing has used observations of geosynchronous objects 90008, 90031, 90214, and 97149 (the object numbers are given in accordance with the numbering in the dynamic database of space objects maintained by the Keldysh Institute of Applied Mathematics, Russian Academy of Sciences). The resulting parameters are used to study the long-term orbital evolution of the objects. It is shown that three objects (90008, 90031, and 90214) are captured in a 1 : 1 resonance with the Earth's rotation velocity and have a stable motion in a rotating coordinate system close to a harmonic oscillator over a 10-year time interval. Object 97149 is not resonant, but its motion remains regular over a time interval of 10 years. [ABSTRACT FROM AUTHOR]

We present the results of a new stage of the long-term photometric study of FG Sge which is a quickly evolving central star of the planetary nebula Hen 1-5. Our new observations carried out on the SAI MSU telescopes in the optical () and infrared (IR) () regions in 2008–2021 and 2013–2021, respectively, allowed us to trace the evolution of the star's brightness in recent years. The most significant observations were performed in 2019 when the star suffered a short clearing of the dust shell and became visible in . Based on the spectral energy distribution of FG Sge in the 0.4–5 m wavelength range we derived the dust shell parameters: the size of dust grains m, the inner radius temperature K, optical depth (), the total mass of dust . After the short-term clearing of the dust shell in 2019, another dust structure was ejected that resulted in the star fading in all the observed bands. Based on the IR brightness and color curves, we estimated the dust depth growth in 2019–2020. [ABSTRACT FROM AUTHOR]

A method is considered for determining the type of observed objects based on identification of the photometric portrait of the object with one of the standard portraits existing in the database of the current and reference photometric portraits of observed objects. The proposed approach allows recognizing the known standard objects irrespective of the presence of a priori information about them. [ABSTRACT FROM AUTHOR]

In 2020, the scientific community will celebrate the 90th birthday of Vitaly Grigorevsky – the Ukrainian astronomer, a specialist in satellite astronomy, a representative of a scientific school of an outstanding Ukrainian scientist, corresponding member of the Ukrainian Academy of Sciences, a director of the Odessa Astronomical Observatory – a professor Vladimir Platonovich Tsesevich. In the article on the basis of complex use of biographical method and methods of bibliographic and source analysis the basic milestones of life and scientific activity of Vitaly Grigorevsky are investigated. The Kherson, Odessa before-Chisinau, Chisinau and Odessa after-Chisinau periods of the scientist's life and work at the Odessa and Chisinau State University, Odessa Technological Institute named after M. V. Lomonosov. The basic directions of scientific researches of the scientist are defined: physical processes in semi-regular variable stars, photometric researches of artificial satellites of the Earth, research of geometry and motion of artificial satellites of the Earth and small planets, optimization of technological processes by mathematical methods with use of electronic computing methods. The contribution of Vitaly Grigorevsky to the formation and development of a new direction of scientific research in the 1960s - photometric observations of artificial satellites of the Earth is shown. The international aspect of Vitaly Grigorevsky's scientific and organizational activity and his work in the Commission on Multilateral Scientific Cooperation between the Academies of Sciences of Socialist Countries are covered. The activity of Vitaliy Grigorevsky as the initiator and coordinator of cooperative research in the field of photometric observations of artificial satellites of the Earth under the SPIN program was noted. The SPIN program included the stations of the People's Republic of Bulgaria, the Czechoslovak Socialist Republic, the Hungarian People's Republic, the German Democratic Republic, the Polish People's Republic, the Soviet Union and the United Arab Republic (Egypt). The little-known facts about the scientist's biography are covered.

The article presents the possibilities of the national ground-based optical space surveillance assets for the conduct of complex optical observations of military and dual-use purpose satellites of the Russian Federation in the interests of the Armed Forces of Ukraine. The results of the complex observations of geostationary (GSO) military and dual-purpose satellites of the Russian Federation are illustrated by the examples of the «Luch-Olimp» (2014-058A) military reconnaissance multipurpose telecom satellite and the dual-purpose meteosat «Electro-L» №1 (2011-001А). Carrying out of complex optical observations of space objects in the visible part of the GSO orbital belt (the far operational strategic space zone) provide operational monitoring of military-space systems of intelligence, communications, combat control and retransmission, early detection and warning of missile launches. Comprehensive analysis, analytical processing and comparison of the results of observations of space objects in the far operational strategic space zone with the results of monitoring of the near operational strategic space zone in which reconnaissance, navigational, topogeodetic, meteorological and manned systems are used, provides opportunities for the formation of a comprehensive operational picture of situation (above the territory of Ukraine in particular) and the early disclosure of the enemy's plan. The actual data received will allow the relevant analytical units of the Armed Forces of Ukraine, based on demagogic signs and peculiarities of the use of satellite and their clusters, to draw conclusions about the likely locations (objects, districts, directions) of the enemy's interest and the likely targets for the use of high-precision armament and missile-guided high-precision weapons. Skillful and effective use of the above-mentioned actual information in the Armed Forces of Ukraine will allow to reduce personnel losses, to preserve weapons and military equipment, to determine in advance the intentions of the enemy, rather than, in general, to carry out more effective counteraction to the enemy. Involvement of national optical observation assets for complex observations of the enemy's spacecraft and their clusters allows to provide effective monitoring of the operational environment in the near-Earth space in the interests of the Armed Forces of Ukraine.

This article highlights the participation of the Ukrainian scientist, Professor Vitaly Mikhailovich Grigorevsky, doctor of physical and mathematical sciences, and representative of the scientific school of Vladimir Platonovich Tsesevich, in the organization and development of international cooperative partnership in the field of satellite astronomy and photometric studies of artificial satellites of the Earth. The activity of the scientist in the coordination of scientific research of the countries of Eastern Europe in 1965- 1973 under the SPIN program, carried out under the auspices of the Astronomical Council of the USSR Academy of Sciences, is discussed. The article explores the main forms of Grigorevsky's scientific cooperation with the world's leading experts in the field of satellite astronomy--the British scientist Desmond King-Hele, the Czech astronomer František Link, Hungarian researchers Iván Almár and D. Toth, and others. Also, the achievements of the Latvian researchers Māris Ābele and Kasimirs Lapushka in the creation of photographic cameras of surveillance of satellites are analysed. [ABSTRACT FROM AUTHOR]

We present the results of our photoelectric UBV observations of the yellow symbiotic star LT Del over 2010–2018. The binary system LT Del, which consists of a bright K giant and a compact hot star with a temperature of ~100 000 K, has an orbital period of 476 days. In 2017 the variable experienced a second low-amplitude (ΔV ~ 0ṃ7) outburst in the history of its studies whose maximum occurred at an orbital phase of 0.15±0.05. The outburst duration was ~60 days. The B–V and U–B colors in the outburst became noticeably bluer. A difference in the photometric behavior of the star in the 1994 and 2017 outburst has been detected. In the orbital cycle preceding the 2017 outburst a secondary minimum with a depth of 0ṃ7 and 0ṃ20 appeared in the B and V light curves, respectively, whose cause is discussed. The phase light and color curves are presented and explained; the position of the star on the color-color diagram is interpreted. We have estimated the parameters of the cool and hot components of the system based on the distance determination from Gaia DR2. [ABSTRACT FROM AUTHOR]

We present the results of our UBV and JHKLM photometry for the semiregular pulsating variable V1027 Cyg, a supergiant with an infrared excess, over the period from 1997 to 2015 ( UBV) and in 2009-2015 ( JHKLM). Together with the new data, we analyze the photometric observations of V1027 Cyg that we have obtained and published previously. Our search for a periodicity in the UBV brightness variations has led to several periods from P = 212 to 320 in different time intervals. We have found the period P = 237 based on our infrared photometry. The variability amplitude, the lightcurve shape, and themagnitude of V1027 Cyg atmaximum light change noticeably from cycle to cycle. The deepest minimum was observed in 2011, when the amplitudes of brightness variations in the star reached the following values: Δ U = 128, Δ B = 110, Δ V = 105, Δ J = 030, Δ H = 035, Δ K = 032, Δ L = 026, and Δ M = 010. An ambiguous correlation of the B − V and U − B colors with the brightness has been revealed. For example, a noticeable bluing of the star was observed during the deep 1992, 2008, and 2011 minima, while the variations with smaller amplitudes show an increase in B − V at the photometric minima. The spectral energy distribution for V1027 Cyg from our photometry in the range 0.36 ( U)-5.0 ( M) μm corresponds to spectral types from G8I to K3I at different phases of the pulsation cycle. Low-resolution spectra of V1027 Cyg in the range λ4400-9200 ˚A were taken during 16 nights over the period 1995-2015. At the 1995 and 2011 photometric minima the star's spectrum exhibited molecular TiO bands whose intensity corresponded to spectral types M0-M1, while the photometric data point to a considerably earlier spectral type. We hypothesize that the TiO bands are formed in the upper layers of the extended stellar atmosphere. We have measured the equivalent widths of the strongest absorption lines, in particular, the infrared Ca II triplet in the spectrum of V1027 Cyg. The calcium triplet (Ca T) with W (Ca T) = 20.3 ± 1.8 ˚A as a luminosity indicator for supergiants places V1027 Cyg in the region of the brightest G-K supergiants. V1027 Cyg has been identified with the infrared source IRAS 20004+2955 and is currently believed to be a candidate for post-AGB stars. The evolutionary status of the star and its difference from other post-AGB objects are discussed. [ABSTRACT FROM AUTHOR]

Abstract: It is well known that the 630.0nm nightglow emission intensity at mid latitudes increased more than twofold in periods of maximum sunspot activity. It is assumed that this phenomenon is caused by variations in solar ultraviolet radiation intensity in solar activity cycles (Fishkova, 1983). In this paper, we present the results of photometric measurements of the nightglow emission intensity at 63°N and 130°E (Yakutsk) in 1990–2007. Moreover, we show the dependence of the 630.0nm emission intensity in magnetically quiet days on solar activity in the 22nd and 23rd cycles. It was established that there is a close relationship between the 630.0nm line nightglow intensity and the solar extreme ultraviolet (EUV) intensity based on SOHO/SEM data, obtained in 1997–2007 with a correlation coefficient of 0.8–0.9. The changes of ionization level of nighttime F2 layer at the Yakutsk station and neutral composition of the upper atmosphere (thermosphere) during the photometric observations have been analyzed. It is shown that the long-term variations of the red line emission intensity are caused by the change of nighttime F2 layer electron density. The nighttime ionization level is related to the electron density of the daytime F2 region which depends on the EUV flux intensity during a solar activity cycle. [Copyright &y& Elsevier]

We present the results of our photometric UBV JHKLM observations in 2008-2011 for the classical symbiotic star V1413 Aql. At the end of 2008, the hot component of V1413 Aql experienced the next strong outburst (Δ V > 25). According to the photometric criterion ( B-V ≈ 09 ± 02), the star was in an active state even in the period preceding the strong 2008 outburst. Two eclipsing minima of the same amplitude were observed for V1413 Aql in 2010 and 2011. Our analysis of the 2011 eclipse has allowed us to estimate the sizes of the components with respect to the orbital semimajor axis if the system is seen edge-on: the radius of the cool component is R/ a = 0.28 and the radius of the hot component is R/ a = 0.17. However, judging by the B-V color index, the eclipse may be noncentral. [ABSTRACT FROM AUTHOR]

We analyze long-term UBV observations and ASAS-3 photometry for five candidates for protoplanetary nebulae-F and G supergiants with infrared excesses at highG alactic latitudes-V340 Ser, IRAS 05113+1347, V552 Pup, V448 Lac, and RV Col. These stars exhibit quasi-periodic multifrequency light variations caused by pulsations with characteristic time scales from 83 to 139 days, depending on the stellar temperature. Cooler stars undergo variations with larger amplitudes and periods. The variations at close frequencies with a period ratio of 1.03-1.09 are responsible for the amplitude modulation revealed for most program stars. [ABSTRACT FROM AUTHOR]

We present new photometric data and analyze long-term UBV observations of three candidates for protoplanetary nebulae—F supergiants with infrared excesses at high Galactic latitudes—IRAS 18095+2704, IRAS 19386+0155, and IRAS 19500-1709. All these stars exhibit quasi-periodic low-amplitude variations caused by pulsations against the background of long-term brightness trends. For IRAS 18095+2704=V887 Her, we have found a pulsation period of 109 days and revealed a linear brightness trend—the star brightens at constant (within the limits of the measurement errors) yearly mean color indices. The light curve of IRAS 19386+0155=V1648 Aql in 2000–2008 is represented by a wave with a fundamental period of 102 days whose modulation with a close period of 98 days leads to variations with a variable amplitude. V1648 Aql also shows a systematic rise in V brightness along with a reddening. IRAS 19500–1709=V5112 Sgr exhibits irregular pulsations with periods of 39 and 47 days. The long-term variability component of V5112 Sgr may indicate that the star is binary. [ABSTRACT FROM AUTHOR]

Abstract: The occurrence rate of SAR arcs during 1997–2007 has been analyzed based on the photometric observations at the Yakutsk meridian (Maimaga station, corrected geomagnetic coordinates: 57°N, 200°E). SAR arcs appeared in 114 cases (∼500h) during ∼370 nights of observations (∼3170h). The occurrence frequency of SAR arcs increases to 27% during the growth phase of solar activity and has a clearly defined maximum at a decline of cycle 23. The SAR arc registration probability corresponds to the variations in geomagnetic activity in this solar cycle. The dates, intervals of UT, and geomagnetic latitudes of SAR arc observations at the Yakutsk meridian are presented. [Copyright &y& Elsevier]

Abstract: We present the results of observational campaigns of asteroids performed at Asiago Station of Padova Astronomical Observatory and at M.G. Fracastoro Station of Catania Astrophysical Observatory, as part of the large research programme on Solar System minor bodies undertaken since 1979 at the Physics and Astronomy Department of Catania University. Photometric observations of six Main-Belt asteroids (27 Euterpe, 173 Ino, 182 Elsa, 539 Pamina, 849 Ara, and 984 Gretia), one Hungaria (1727 Mette), and two Near-Earth Objects (3199 Nefertiti and 2004 UE) are reported. The first determination of the synodic rotational period of 2004 UE was obtained. For 182 Elsa and 1727 Mette the derived synodic period of and , respectively, represents a significant improvement on the previously published values. For 182 Elsa the first determination of the magnitude relation is also presented. [Copyright &y& Elsevier]

We present the results of our photometric ( BV R) and spectroscopic CCD observations of NGC 304 and NGC 7625, candidate polar-ring galaxies, performed with the 6-m Special Astrophysical Observatory telescope. For NGC 304, such a study has been carried out for the first time. We have obtained basic integrated characteristics of the galaxies and determined their morphological types (S0 for NGC 304 and Sa for NGC 7625). The absolute magnitudes of the galaxies, M B = −20m.81 for NGC 304 and M B = −19m.34 for NGC7625, are indicative of their fairly high luminosities. The disk and bulge parameters have been determined forNGC 304 (µ0 = 20m.60, h = 3.86 kpc, µ e = 21m.59, r e = 1.26 kpc in the B band); these correspond to the parameters of S0-type objects. The rotation velocity for NGC 304 (200 km s−1) reaches its maximum at a galactocentric distance of 3.1 kpc, which yields a mass estimate for the galaxy of 2.8 × 1010 $$ \mathcal{M}_ \odot $$ . The observed photometric features at the center of NGC 304 indicate that it may have an inner ring structure, although we have failed to confirm the existence of two kinematic systems based on our spectroscopic observations. In NGC 7625, the disk makes a dominant contribution to the total brightness. The derived integrated color indices ( B-V = 0m.81 and V-R = 0m.61) agree with previous determinations of other authors. We have estimated the учештсешщт in the inner galactic regions. In the outer regions, we have detected structures with bluer colors ( B-V = 0m.60), which may be indicative of a polar ring with a minor stellar component. [ABSTRACT FROM AUTHOR]

The Infrared Space Observatory (ISO) was the world’s first true orbiting infrared observatory. Equipped with four versatile scientific instruments, it was launched by an Ariane 44P in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the universe at infrared wavelengths (2.5–240 μm). Its 60-cm diameter telescope was cooled by superfluid liquid helium to temperatures of 2–4 K. The mission was a great technical, operational and scientific success, with most satellite sub-systems operating far better than specifications, while the scientific instruments returned unprecedented results ensuring that its scientific output impacted practically all fields of astronomy. During its routine operational phase, which lasted until April 1998 – almost a year longer than specified, ISO successfully made some 30,000 individual imaging, photometric, spectroscopic and polarimetric observations ranging from objects in our own solar system right out to the most distant extragalactic sources. ISOs data archive – – opened to the community in December 1998 and, including data from calibration and auxiliary mode observations, contains about 150,000 data sets. Since 1996 to date about 1000 ISO papers have been published in the refereed literature, and many more in conference proceedings. A summary of the mission – including some of its highlights – is presented, followed by a description of current and future activities. [Copyright &y& Elsevier]

We present our B, V, Rc, and Ic observations of a 3′.6 × 3′ field centered on the host galaxy of GRB 000926 (α2000.0 = 17h04m11s, δ2000.0 = +51°47′9″.8). The observations were carried out on the 6-m Special Astrophysical Observatory telescope using the SCORPIO instrument. The catalog of galaxies detected in this field includes 264 objects for which the signal-to-noise ratio is larger than 5 in each photometric band. The following limiting magnitudes in the catalog correspond to this limitation: 26.6 (B), 25.7 (V), 25.8 (R), and 24.5 (I). The differential galaxy counts are in good agreement with previously published CCD observations of deep fields. We estimated the photometric redshifts for all of the cataloged objects and studied the color variations of the galaxies with z. For luminous spiral galaxies with M(B) < -18, we found no evidence for any noticeable evolution of their linear sizes to z ∼ 1. [ABSTRACT FROM AUTHOR]