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A description of the software designed for controlling robotic observatories is given. Its main features and functional capabilities are described. Special attention is paid to approaches to improving the utilization of the telescope observation time, which is its main resource. A solution for the automation of routine observational tasks the execution of which directly affects the efficiency of the entire system is proposed. It is shown that the use of the new software increased the total coverage of the celestial sphere during an observational night by 25–30%. The main discoveries and achievements of two remote robotic observatories controlled by this software are presented. During the operation of these observatories, more than half-a-million astrometric measurements of small bodies of the Solar System were made, more than hundred photometric light curves were obtained, and a number of near-Earth asteroids and comets were discovered. The optical component of the afterglow of gamma-ray bursts was observed.

We have studied the kinematic properties of the candidates for hot subdwarfs (HSDs) selected by Geier et al. from the Gaia DR2 catalogue. We have used a total of 12 515 stars with relative trigonometric parallax errors less than 30\%. The HSDs are shown to have different kinematics, depending on their positions on the celestial sphere. For example, the sample of low-latitude $(|b, Comment: 18 pages, 4 figures, 4 tables

The Spectrum-Roentgen-Gamma (SRG) project is intended for surveying the entire sky in the X‑ray band using two telescopes mounted onboard the spacecraft of the same name (SRG). In addition, some specially chosen areas of the sky and some radiation sources are planned to be investigated after the completion of the survey. The spacecraft was planned to be launched in 2018 into the vicinity of solar-terrestrial collinear libration point L2, using the Proton-M launch vehicle with a DM-03 block upper stage. The technology for completely surveying the celestial sphere consists in scanning by rotating the parallel axes of telescopes around the spacecraft axis, which roughly followed the direction to the Sun. The measurement data, stored onboard the spacecraft, would then be transmitted to the ground receiving stations using the mean gain antenna, the axis of which coincided with the spacecraft’s axis of rotation. This imposed some constraints on the mission design. These constraints included the permissible amplitude of the trajectory of spacecraft motion relative to the libration point in the direction orthogonal to the Sun–Earth line. In addition, the consumption of the onboard propellant was allowed only for orbit correction needed for keeping the spacecraft near the libration point. In this connection, a method was developed using the upper stage in order to decrease the mentioned amplitude down to acceptable values, in the conditions of the requirements imposed on the unit. The paper presents an assessment of its effectiveness.

The systematic differences between the trigonometric parallaxes of the Hipparcos and TGAS catalogues have been investigated using spherical harmonics. The most significant harmonics in the expansion have been determined. The distribution of the parallax difference dispersion in various regions of the celestial sphere has also been studied. The distribution of the rms deviation has the simplest form in the ecliptic coordinate system.

The direction of the twilight sky background polarization on the celestial sphere far from the solar vertical depends on the ratio of single and multiple scattering contributions. Variations in the polarization direction during twilight reflect the evolution of the properties and background emission components and can be used to control the procedure of selecting single scattering. This makes it possible to specify the temperature measurements according to the molecular scattering of solar emission and the contribution of dust scattering in the upper mesosphere. The results of the temperature measurements during the observations in 2011–2015 have been presented.

New arguments supporting the reality of large-scale fluctuations in the density of the visible matter in deep galaxy surveys are presented. A statistical analysis of the radial distributions of galaxies in the COSMOS and HDF-N deep fields is presented. Independent spectral and photometric surveys exist for each field, carried out in different wavelength ranges and using different observing methods. Catalogs of photometric redshifts in the optical (COSMOS-Zphot) and infrared (UltraVISTA) were used for the COSMOS field in the redshift interval $0.1 < z < 3.5$, as well as the zCOSMOS (10kZ) spectroscopic survey and the XMM-COSMOS and ALHAMBRA-F4 photometric redshift surveys. The HDFN-Zphot and ALHAMBRA-F5 catalogs of photometric redshifts were used for the HDF-N field. The Pearson correlation coefficient for the fluctuations in the numbers of galaxies obtained for independent surveys of the same deep field reaches $R = 0.70 \pm 0.16$. The presence of this positive correlation supports the reality of fluctuations in the density of visible matter with sizes of up to 1 000 Mpc and amplitudes of up to 20% at redshifts $z \sim 2$. The absence of correlations between the fluctuations in different fields (the correlation coefficient between COSMOS and HDF-N is $R = -0.20 \pm 0.31$) testifies to the independence of structures visible in different directions on the celestial sphere. This also indicates an absence of any influence from universal systematic errors (such as "spectral voids"), which could imitate the detection of correlated structures., 12 pages, 13 figures

A new definition of hazardous celestial bodies (HCBs) is introduced, in which the lower limit of the size of a HCB is reduced to 10 m. A new definition for threatening and collisional orbits of DCBs is introduced. The main astronomical factors that must be taken into account when creating systems for the detection of HCBs are analyzed. The most important of these are the uniformity of the distribution of points (regions) for the appearance of HCBs on the celestial sphere in near-Earth space and the practical limit for the velocity of approach of a HCB of 20 km/s (for 90% of bodies). It is shown that the creation of a system for the nearby detection of asteroids and comets arriving from the daytime sky requires the use of a space-based system. A concept for such a system, in which one or several optical telescopes are placed in the vicinity of the libration point L1 for the Sun—Earth system, is developed. Preliminary plans for such a system, called the System for the Detection of Daytime Asteroids (SDDA), are briefly described.

A method for a kinematic analysis of stellar radial velocities using spherical harmonics is proposed. This approach does not depend on the specific kinematic model and allows both low-frequency and high-frequency kinematic radial velocity components to be analyzed. The possible systematic variations of distances with coordinates on the celestial sphere that, in turn, are modeled by a linear combination of spherical harmonics are taken into account. Theoretical relations showing how the coefficients of the decomposition of distances affect the coefficients of the decomposition of the radial velocities themselves have been derived. It is shown that the larger the mean distance to the sample of stars being analyzed, the greater the shift in the solar apex coordinates, while the shifts in the Oort parameter A are determined mainly by the ratio of the second zonal harmonic coefficient to the mean distance to the stars, i.e., by the degree of flattening of the spatial distribution of stars toward the Galactic plane. The distances to the stars for which radial velocity estimates are available in the CRVAD-2 catalog have been decomposed into spherical harmonics, and the existing variations of distances with coordinates are shown to exert no noticeable influence on both the solar motion components and the estimates of the Oort parameter A, because the stars from this catalog are comparatively close to the Sun (no farther than 500 pc). In addition, a kinematic component that has no explanation in terms of the three-dimensional Ogorodnikov-Milne model is shown to be detected in the stellar radial velocities, as in the case of stellar proper motions.

A method for determining the velocity field parameters free from the distortions due to the systematic variations of stellar parallaxes over the celestial sphere is proposed. The method is based on the approximation of parallaxes as a function of coordinates on the sphere using spherical harmonics and can be applied in those cases where the solar motion cannot be eliminated from the stellar proper motions. Numerical experiments have shown that our method is able to obtain accurate coordinates of the solar apex and to calculate the kinematic parameters of the Ogorodnikov-Milne model to within three coefficients of the decomposition of parallaxes into first-order spherical harmonics. Examples of applying the method to the stellar proper motions of the Hipparcos catalogue, which admits checking the results using trigonometric parallaxes, are provided. Such a check has been found to yield a positive result only for nearby stars at heliocentric distances that do not exceed 400 pc and for which the parallaxes were determined with a relative error of at least 30%. An interesting feature of this method is the possibility to construct the shape of the figure which is formed by the deviations of the parallaxes from the sphere corresponding to the average parallaxes of the stars under consideration. It should be specially emphasized that all of this is done in the complete absence of information about the stellar parallaxes. The “solar terms” of the stellar proper motions that are formed by the products of the parallaxes by the solar motion components relative to the centroid of stars are the main source of information about the parallaxes here.

We study the effect of systematic variations in stellar parallaxes over the celestial sphere on the results of a kinematic analysis of stellar proper motions. Our approach is based on the representation of stellar parallaxes by scalar spherical harmonics and on the decomposition of stellar proper motions into a system of vector spherical harmonics. We derive theoretical relations that relate the coefficients of the decomposition of stellar proper motions into toroidal and spheroidal harmonics to the coefficients of the decomposition of stellar parallaxes into scalar spherical harmonics. We have established that the systematic variations of parallaxes over the celestial sphere distort all parameters of the linear Ogorodnikov-Milne model and can be responsible for the appearance of beyond-the-model harmonics. We have performed a kinematic analysis of the proper motions of blue-white and red giants based on Hipparcos data. The parallaxes of blue-white giants show a strong dependence on Galactic latitude (with predominant contraction along the Galactic equator). In contrast, the deviations of the parallaxes from the mean for red giants are localized only in two regions of the celestial sphere. For these samples, the effect of parallax variations over the celestial sphere on kinematic parameters has turned out to be comparable to their rms errors. The global solutions performed using both samples have revealed strong beyond-the-model kinematic effects described by second-order toroidal harmonics and third-order spheroidal harmonics. Using the solutions performed separately in the northern and southern Galactic hemispheres, we have established that not the systematic variations of parallaxes over the celestial sphere but the retardation of Galactic rotation with increasing distance of stars from the principal Galactic plane is mainly responsible for the appearance of these harmonics. Based on these samples of stars, we have estimated the magnitude of the vertical Galactic rotation velocity gradient to be 18.0±2.9 and 22.7±2.2 km s−1 kpc−1, respectively.

We discuss the possibility of identification of point-like gamma-ray sources (PGS) with small-scale dark matter (DM) clumps in our Galaxy. Gamma rays are supposed to originate from annihilation of DM particles in the clumps, where the annihilation rate is supposed to be enhanced, besides higher density, due to smaller relative velocities v of DM particles. We parametrized the annihilation cross section σ ann(v) in the form of an arbitrary power-law dependence on the relative velocity v with/without the Sommerfeld-Gamow-Sakharov factor, implying the existence of a new Coulomb-like interaction. Adopting different parameters of the cross-section and the clump, satisfying the condition Ω ≲ 0.2 on the density of DM particles, they are constrained by comparison with the Fermi/LAT data on unidentified PGS as well as on diffuse γ radiation; the results are applied to concrete DM candidates. This analysis is found to be sensitive enough to the existing uncertainty in the DM density profiles in the clump, which can provide a tool for their test. We also discuss the possibilities where a gamma-radiating clump changes visibly its position on the celestial sphere and it is seen as a spatially extended gamma source (EGS), which can be probed in future experiments like Gamma-400.

A method for determining the celestial coordinates of the center of the disk of the Earth from satellite observations with an accuracy of 1–5 arcseconds is suggested. The choice of the most suitable wavelength range is substantiated.

Data from the Hipparcos catalog are used to study the internal kinematics of the Hyades cluster. Cluster members whose proper motions and parallaxes are known with precisions not less than 5 mas/yr and 3 mas were used. The proper motions were reduced to the cluster center. A correlation between a component of the tangential velocity and the parallax provides evidence for possible rotation of the cluster. The total velocity gradient is 0.04±0.03 km s−1 pc−1. The rotation axis is located perpendicular to the direction to the Hyades apex on the celestial sphere.

Two new methods are described for finding the orbit of a small celestial body from three or more pairs of angular measurements and the corresponding time points. The methods are based on, first, the approach that has been developed previously by the author to the determination, from a minimum number of observations, of intermediate orbit considering most of the perturbations in the bodies’ motion and, second, Herget’s algorithmic procedure enabling the introduction of additional observations. The errors of orbital parameters calculated by the proposed methods are two orders of magnitude smaller than the corresponding errors of the traditional approach based on the construction of an unperturbed Keplerian orbit. The thus-calculated orbits of the minor planets 1566 Icarus, 2002 EC1, and 2010 TO48 are used to compare the results of Herget’s multiposition procedure and the new methods. The comparison shows that the new methods are highly effective in the study of perturbed motion. They are particularly beneficial if high-precision observational data covering short orbital arcs are available.

The studies of the cosmic gamma-ray bursts and soft gamma repeaters that have been performed in the Russian-American Konus-Wind experiment during the last several years have been summarized. The experiment has been continuously performed using the Konus Russian scientific instrument on the Wind American spacecraft since 1994 under the optimal interplanetary space conditions in the absence of noise caused by the Earth’s radiation belts and the shadowing of detectors. Two high-sensitivity detectors have constantly observed the entire celestial sphere and recorded detailed time and spectral characteristics of bursts in a wide range of energies (20 keV–15 MeV). The Konus-Wind data have been widely used in the present-day multiwave studies of gamma-ray bursts.

A modification of the Laplace method for the determination of a preliminary orbit of a body moving in the plane of the ecliptic is presented. It is shown that on the basis of three close positions on the celestial sphere, the parabolic orbit can be determined in cases, when the classical Laplace method is not suitable. The numerical estimation of the number of possible solutions is carried out, and their spatial distribution depending on initial conditions is shown. An example of the determination of an orbit for the comet C/2007 N3 (Lulin) is given.

We suggest a method for extracting important cosmological information from observational data on galaxy proper motions on the celestial sphere. These data can be used to reconstruct the three-dimensional velocities of galaxies relative to the cosmicmicrowave background (peculiar velocities), and to separate the Hubble and peculiar components of the observed redshifts in a large volume for the first time. As a result, it is possible to determine the Hubble constant accurately and independently using the radial velocities of comparatively close galaxies (up to 50 Mpc), and to determine distances to the galaxies and the mass distribution in the neighborhood of the Local group of galaxies. The proposed task may be solved using the future “Millimetron” space radio interferometer.

Results of observations of the five candidate GPS sources J0626+8202, J0726+7911, J1044+8054, J1823+7938, and J1935+8130 are presented. GPS sources are extragalactic sources whose spectral peaks are near several GHz. These objects were observed on the RATAN-600 radio telescope from 1999 through 2010 at 1.1, 2.3, 4.8, 7.7, 11.2, and 21.7 GHz. These radio sources were selected from a complete sample (Sv ≥ 200 mJy at 1.4 GHz) in the vicinity of the North Celestial Pole (+75° ≤ δ ≤ +88°); four are considered as GPS candidates for the first time here. Their spectral properties, variability and morphology are analyzed, and confirms that these can be classified as GPS sources. These four to five GPS sources probably comprise a complete sample of this class of object in this region of the celestial sphere.

Using visual, photographic, and photoelectric measurements, we have constructed a historical light curve for the young binary system UY Aur on an interval longer than 100 yr. About a quarter of all magnitude estimates have been obtained for the first time from photographic plates of the Sternberg Astronomical Institute and Harvard College Observatory Astronomical Plate Stacks. Analysis of the light curve and the magnitude dependences of the polarization and color has led us to the following conclusions. Cyclic variations in the seasonally mean brightness of the binary’s primary component UY Aur A with a period of ≃16.3 yr occurred from the mid-1920s to the mid-1940s and after 1986. The variations are caused by the change in the rate of disk accretion onto the star attributable to the motion of the hypothetical companion UY Aur C around the primary star in an orbit with a semimajor axis of ≃ 6 AU. From the early 1950s to the mid-1980s, the periodicity of the seasonally mean variations was not noticeable due to nonperiodic eclipses of UY Aur A by gas-dust clouds. Between 1945 and 1974, another gas-dust cloud obscured and still obscures the component UY Aur B, causing its mean optical brightness to drop by several magnitudes. The role of the clouds that caused an almost simultaneous eclipse of the stars, whose separation in projection onto the celestial sphere exceeds 100 AU, is played by the denser and puffed-up regions of their accretion disks. These regions are the result of a dynamical interaction between the binary’s stars and the outer circumbinary accretion disk. The extinction variations with time are attributable to orbital motion of the binary’s stars and azimuthal inhomogeneity of the clump regions in the disks. A number of observational tests are suggested to verify our conclusions.

We propose a new method for the determination of the preliminary orbit of a small celestial body using three pairs of its angular coordinates in three moments of time. The method is based on the use of the intermediate orbit we constructed earlier using three position vectors and the corresponding time moments. This intermediate orbit accounts for the main part of the perturbations of the motion of the body under study. We compare the results obtained by the classical Lagrange-Gauss method, Herrick-Gibbs method, generalized Herrick-Gibbs method, and the new method by the examples of the determination of the orbit of the small planet 1566 Icarus. The comparison showed that the new method is a highly efficient tool for the study of perturbed motion. It is especially efficient when applied to high-precision observational data covering short arcs of the orbit.

A method of constructing three-dimensional orbits with a necessary evolution in the system the Sun — (Earth + Moon) is described. The orbit (promising from the viewpoint of solving formulated research problems) of the Millimetron spacecraft is suggested. Feasibility of such an orbit is demonstrated, as well as a possibility to observe with its help the majority of objects on the celestial sphere and to transmit the data to the Earth.

The energy spectrum and anisotropy of primary cosmic rays, as well as the lateral distribution functions of electrons and muons in extensive air showers (EASs) with E 0 ≥ 1017 eV, are presented according to the Yakutsk EAS array data. It has been shown that the spectrum and lateral distribution functions in some energy ranges have different shapes for the particles that arrive from the disc of the Supergalaxy (Local Supercluster of galaxies) and from the other part of the celestial sphere. This is interpreted as the manifestation of the interaction of extragalactic primary cosmic rays with the gas of the Supergalaxy that possibly leads to the production of new ultra-high-energy particles.

A statistical study of motions of images of distant extragalactic sources, such as quasars on the celestial sphere, due to the action of weak gravitational microlensing is presented. It was assumed that the parallax of the lens was 10 milliarcseconds (mas), the mass of the lens was 1 M⊙, and the proper motion was µ = 30 mas. The initial point for the motion of the lens (a star in our Galaxy) was taken to be the boundary of a region with a radius of ϑ = 100 mas and its center coincident with the distant source. The simulations for each trajectory were carried out in steps, with the time step being 0.1 year. The number of sources “launched” over the computational period was 5000. The appearance of the trajectories for the source images is presented; 57% of the total number of sources that participated in the simulations showed motions of 0.7–1.0 mas.

The structure of the proper-motion diagrams for an ensemble of nearby field stars is analyzed using a simple model. For comparison, the observed proper-motion diagram is constructed using data of the Hipparcos catalog. A complete description is given of the modification of the van Altena method, which allows stars with similar space motions to be identified based on their proper motions. In the original version of this method, the stars had to be located within one-quarter of the celestial sphere, whereas our version is free of this restriction.

Arrival directions of gamma-ray-initiated showers with energies over 1014 eV detected by the Bolivian and Tien Shan high-altitude arrays have been analyzed. Their distribution over the celestial sphere is nonuniform, and in the range of galactic latitudes b⩽30° it is similar to the distribution of Seyfert galaxies, which are at distances ∼1.5–200 Mpc from us, if the Hubble constant is 75 km/s·Mpc. Assuming that Seyfert galaxies are sources of protons with energies higher than 3×1019 eV, the gamma-rays can be generated in collisions of extragalactic protons with relict photons and in subsequent electromagnetic cascades in the extragalactic space. The upper limit on the extragalactic magnetic field, B≪10−9 G, is derived.

The arrival directions of showers with energies above 3.2·1019 eV, recorded by the Akeno and AGASA detectors, are analyzed. Their distributions over the celestial sphere are compared with the distributions of possible sources of protons of such high energies. An analysis using three standard deviations of uncertainty in the determination of the arrival directions of the showers shows that the sources of the protons initiating the showers are nuclei of active galaxies with red shifts z≤0.0092, i.e. their distance from us does not exceed 40 Mpc, assuming the Hubble constant is H=75 km/s·Mpc.