Analysis of the optics of the 2.5-m telescope of the Sternberg Astronomical Institute

The results of alignment and acceptance tests of the optics system of the 2.5-m telescope installed at the Caucausus Mountain Observatory of the Sternberg Astronomical Institute in 2013–2015 are reported. The optical elements of the Ritchey–Chrétien system of the telescope were manufactured by REOSC (France). Measurements of aberrations were carried out using a specially manufactured Shack–Hartmann wavefront sensor. Adjustment of the load-distribution mechanisms of the primary mirror and automatic correction for bending of the structure have made it possible to achieve the target image quality at all operational positions of the telescope, corresponding to 80% of the energy being concentrated in a circle 0.3″ in diameter. Factory interferograms of the mirrors and methods for measuring their abberation using stellar images are presented.     

Coronagraphic methods for detecting faint astronomical objects near bright ones: Application to the 2.5-m telescope of Sternberg Astronomical Institute

Possible methods for reducing the instrumental background of astronomical telescopes are discussed: the classical Lyot coronagraphic method, the multi-cascade coronagraphic method, the use of special masks in the plane of the entrance aperture, and the use of super-smooth and medium-smooth primary optics. For the first time, analytical expressions describing the intensity distribution at the exit pupil are presented for the case when a mask is placed in the primary focal plane in order to block the light from a bright object. An algorithm for computing the point-spread function (PSF) of a coronagraphic telescope employing super-smooth primary optics and the coronagraphic method is proposed. Computed PSFs for the 2.5-m telescope of the Caucasian Mountain Observatory of Sternberg Astronomical Institute are presented, without allowance for diffusive and turbulent scattering in the Earth’s atmosphere, and for operation both without coronagraphic elements and in the coronagraphic mode of the telescope.     

Observability of Single Neutron Stars at SRG/eROSITA

Astronomy Reports - A four-year sky survey with the use of the eROSITA telescope on board the Spektr-RG observatory with focusing optics will provide the best coverage in the soft (0.5–2 keV)...     

Analysis of errors in the tracking mechanisms of the 1.25-m telescope of the Crimean Laboratory of the SAI and the 1.5-m telescope of the Maidanak Observatory

Low-frequency (0–0.5 Hz) errors in the positions of stars in the focal plane of the ZTE 1.25-m telescope of the Crimean Laboratory of the Sternberg Astronomical Institute and the AZT-22 1.5-m telescope of the Maidanak Observatory in Uzbekistan are analyzed using data obtained during the operation of two optical compensators designed to correct the tilt of incoming wave fronts. A spectral analysis is used to identify possible origins of these errors. The amplitudes of periodic errors in the main worm-and-worm gears of the tracking mechanisms have been measured to be 1.5″ (a period of 240 s) for the 1.25-m telescope and 0.15″ (167 s) for the 1.5-m telescope. The rates of constant drifts have also been determined.     

Spectroscopy of Globular Clusters in the Spheroidal Dwarf Galaxy IKN

Astronomy Reports - Moderate resolution spectra of four globular clusters in the dwarf spheroidal galaxy IKN obtained with the 6-m telescope of the Special Astrophysical Observatory have been used...     

On the Status of the Star Schulte 12 in the Association Cyg OB2

Astronomy Reports - High-resolution spectra of the LBV candidate Schulte 12 in the Cyg OB2 association were obtained at the 6-m BTA telescope with the NES echelle spectrograph on the arbitrary...     

Spectral studies with the Special Astrophysical Observatory 6 m and RATAN-600 telescopes

We present optical identifications, classifications, and radio spectra for 19 radio sources from a complete sample in flux density with declinations 10°–12°30′ (J2000) obtained with the 6-m optical telescope (4000–9000 Å) and RATAN-600 radio telescope (0.97–21.7 GHz) of the Special Astrophysical Observatory. Twelve objects with redshifts from 0.573 to 2.694 have been classiffied as quasars, and two objects with featureless spectra as BL Lac objects. Four objects are emission-line radio galaxies with redshifts from 0.204 to 0.311 (one also displaying absorption lines), and one object is an absorption-line galaxy with a redshift of 0.214. Radio flux densities have been obtained at six frequencies for all the sources except for two extended objects. The radio spectra of five of the sources can be separated into extended and compact components. Three objects display substantial rapid (on time scales from several days to several weeks) and long-term variability of their flux densities.     

云相态的卫星遥感研究进展

云相态不仅是气象学和气候学研究的重要参量,也是卫星云参数反演的关键要素,其识别的准确性直接关系到光学厚度、有效粒子半径等光学和微物理参数的反演精度.卫星遥感技术的发展为云相态的识别提供了前所未有的技术手段.对能够提取云相态信息的主要星载遥感源进行了介绍,重点总结了近30年来国内外利用星载被动光学遥感资料、偏振辐射资料以及主动雷达资料进行云相态反演的基本原理、方法以及技术特点,最后针对目前云相态反演工作中存在的一些问题和发展趋势进行了探讨.     

BVIc photometry of classical cepheids from the ASAS-3 catalog

In 2008–2010, we obtained 6095 CCD frames in the BV I _c photometric systemfor 49 classical Cepheids discovered in the ASAS-3 project. The observations were obtained on the 76-cm telescope of the South African Astronomical Observatory (SAAO, RSA) and the 40-cm telescope of the Cerro Armazones Observatory of the Catholic University of the North (OCA, Chile), with a SBIGCCD ST-10XME camera. We present tabulated observations, light curves, and revised elements for the brightness variations.     

Internal structure of simple S-bursts of Jovian decameter-wavelength emission

The fine internal structure of fundamental Jovian decameter-wavelength millisecond outbursts (S-bursts) is studied. Broadband data obtained with the Waveform Receiver (WFR) on the UTR-2 decameter radio telescope have been analyzed using wavelet transforms. The millisecond S-bursts have a complex internal pulse microstructure, whose parameters are presented. Our results offer new prospects for understanding Jovian decameter-wavelength emission.     

Objects from a cross-identification of the IRAS and low-frequency Texas radio catalogs

A cross-identification of objects in the low-frequency (365 MHz) Texas radio catalog and in IRAS catalogs at four infrared wavelengths has yielded a list of 715 objects for further studies. Objects with steep spectra for which the difference in the centers of gravity of the radio and infrared sources was less than 3″ were selected from this list. Seventeen of the objects have been observed at six wavelengths using the RATAN-600 radio telescope. Spectra of nine objects from the initial list for which there were candidate optical counterparts were obtained using the 2.1-m telescope of the INAOE. The results of these observations are discussed. The presence of steep spectral indices for the radio sources is confirmed. The possible optical counterparts include interacting galaxies, an infrared galaxy, two emission-line galaxies, and a candidate BL Lac object. Optical images of the optical counterparts are presented together with radio and optical spectra.     

Microvariability of line profiles in the spectra of OB stars: III. The supergiant ρ LEO

We observed the bright supergiant ρ Leo (B1 lab) in January–February 2004 using the 6-m telescope of the Special Astrophysical Observatory (Russia) and the 1.8-m telescope of the Bohyunsan Optical Astronomy Observatory (South Korea). 47 spectra with high time resolution (4–10 min), signal-to-noise ratios 300–1000, and spectral resolutions 45 000–60 000 were obtained. We detected variability in the HeI, SiII, SiIII, and NII line profiles, which may be due to rotational modulation of the profiles and photospheric pulsations of ρ Leo. The possible influence of the stellar magnetic field on the line-profile variations is discussed.     

Value of Information Introduced by a Resource Model Updating Framework

A primary concern of the mining industry is to meet production targets, which are required and defined by customers. Deviations from these targets, in terms of quality and quantity, highly affect the economical aspect. Recently, an efficient resource model updating framework concept has been proposed aiming for the improvement of raw material quality control and process efficiency in any type of mining operation. The concept integrates online sensor measurements, obtained during production, into the resource model. In this way, due to the spatial variability, quality attributes of the blocks that will be produced in the next days or weeks are being updated based on real-time measurements. The concept has been applied in a lignite field with the aim of identifying local impurities in a lignite seam and to improve the prediction of coal quality attributes in neighbouring blocks. This paper investigates the added value of using the resource model updating framework by using the value of information analysis. The expected benefit of additional information (integration of the online sensor measurements into the resource model) is compared to a case where there is no additional information integrated into the process. These benefits are evaluated based on the economic impact determined by applying the resource model updating framework in mine planning.

     

An experimental test of the photometric calibration of the guide star catalog for the Spectrum-UV (WSO/UV) project

A test of the photometric calibration accuracy for the guide-star catalog (Master Catalog) of the Spectrum-UV project (World Space Observatory—Ultraviolet) has been performed using CCD observations in a spectral band close to that of the guide sensor system of the T-170M space telescope. The mean photometric uncertainty of the Master Catalog at 14 ^m –17 ^m is 0.23 ^m ; variations in this uncertainty over the sky are within a factor of two. About 2% of the stars in the Master Catalog were found to have photometric errors in excess of 2 ^m . We analyze the correspondence of large photometric errors to flags of the Master Catalog.     

Refractive shift in the position of the pulsar PSR B0329+54, measured at 111, 610, and 2300 MHz

The results of an analysis of timing data for the pulsar PSR B0329+54 obtained in 1968–2012 on the Large Scanning Antenna of the Pushchino Radio Astronomy Observatory at 111 MHz, the 64 m DSS-14 telescope of the Jet Propulsion Laboratory at 2.3 GHz, and the 64 m telescope of the Kalyazin Radio Astronomy Observatory at 610 MHz are presented. The astrometric and spin parameters of the pulsar are derived at a new epoch. The coordinates of the pulsar and its proper motion measured at the three frequencies differ. These differences have a systematic character, and are interpreted as a secular, refractive shift in the apparent position of the pulsar that arises because it is observed through large-scale inhomogeneities of the interstellar medium, leading to variations in the angle of refraction.     

Spectrum of the variable component of the radio source J0157+7442

The spectrum of the maximum values of the variable component of the radio source J0157+7442 is presented. The flux densities obtained on the RATAN-600 radio telescope at centimeter wavelengths in 2009 and 2010 are minimum for all observations of the source, and it was assumed that the variable component was absent in these years. After subtracting these RATAN-600 data from the upper envelope of all available flux density data, the spectrum of the variable component was obtained. The form of the spectrum of the variable component is typical of a nonuniform, spherically symmetric source with synchrotron self-absorption.     

Spectral studies of several galaxies in the vicinity of the cluster A0569

The results of spectroscopic studies of several faint galaxies projected onto the cluster A0569 are presented. The observations were carried out at Cananea (Mexico) on the 2.12-m telescope of the Guillermo Haro Observatory equipped with a Boller and Chivens spectrograph. The redshifts of these galaxies have been determined based on their absorption and emission lines.     

Detection of a cyclotron line in the radio spectrum of a solar active region and its interpretation

Observations of the active region AR 7962 obtained at 2–32 cm on the RATAN-600 radio telescope on May 10–12, 1996, are presented. The high-resolution measurements detected a narrow feature near 8.5 cm against the background of the smooth spectrum of the local source associated with sunspots. This narrow-band emission is identified with a bright, pointlike, high-frequency source at 1.7 cm recorded on maps made using the Nobeyama radio telescope. The characteristics of the observed line (lifetime 3 days, brightness temperature of the order of several million Kelvin, relative width of about 10%) suggest that it can be explained as thermal cyclotron radiation at the third harmonic of the electron gyrofrequency from a compact source containing a dense, hot plasma; the corresponding higher frequency emission could be due to thermal Bremsstrahlung. Analysis of the RATAN-600 and Nobeyama data can be used to probe the magnetic field, kinetic temperature, and electron density in the radiation source in the corona.     

Radio and optical spectra of objects from two complete samples of radio sources

We present optical identifications and radio spectra for ten radio sources from two flux-density-complete samples. Radio variability characteristics are presented for four objects. The observations were obtained on the RATAN-600 radio telescope at 0.97–21.7 GHz and the 2.1 m telescope of the Haro Observatory in Cananea, Mexico at 4200–9000 Å. Among the ten objects studied, three are quasars, four are BL Lac objects, two are radio galaxies, and one is a Sy 1 galaxy. Two of the sources identified with BL Lac objects, 0509+0541 and 0527+0331, show rapid variability on time scales of 7–50 days.     

Evolution of OH and H2O Maser Emission in the Active Star Formation Region NGC 2071

Astronomy Reports - We present the observation results of the star forming region NGC 2071 in the 1.35-cm H2O line and 18-cm OH lines obtained with the 22-m radio telescope in Pushchino (Russia)...