... The most precisely determined characteristic for accreting neutron stars (NS's) is their period. ... Period changes show fluctuations. ... Some applications of stochastic processes in astrophysics especially in accreting systems were discussed in Lipunov (1987),Hoshino Takeshima (1993) and Lipunov (1992).In Hoshino Takeshima (1993) the authors, using simple models of MHD turbulence, try to explain aperiodic changes in X-ray luminosity of X-ray pulsars. ... Here, -constant angular momentum. ...

... They were determined as a result of orbit improving on the base of all kinds of optical observations available in the catalog of observations of the Minor Planet Center on March 16, 2014 (radar observations have not been used at this stage). ... As the MPC orbits do not all were improved simultaneously with EMP orbits, only 383866 sets of elements were used for data comparison (for selected sets of elements process of improvement had started with the use of the same observations). ...

THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE BY MEANS OF DIGITAL MODELS. ... The surface brightness of Mercury was measured Danjon (1933, 1949, 1953) and Harris (1961) in phase angle 3o-123o. The analysis of the various data of the integral photometric gives the results of determination of the main photometric constants for Mercury. ... THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE: S.G. Pugacheva The surface brightness of the Mercurian images was established on the geologic map Mercury. ...

... The absolute flux calibration of NICMOS will be calculated from observations of standard stars with known flux distributions F( ). ... In order to expand the set of IR standard stars in the appropriate flux range for NICMOS, M. Rieke, R. Thompson, and collaborators at the University of Arizona are making photometric observations of solar-analog stars, which will be used to normalize the solar spectrum to the observed IR magnitudes. ... Relative flux references accurate to 1.5% for standard...

Institute of Applied Astronomy Russian Academy of Sciences Method of Determining the Orbits of the Small Bodies in the Solar System Based on an Exhaustive Search of Orbital Planes Dmitrii Vavilov, Yurii Medvedev Introduction to the problem: Let we have n 3 positional observations of a body: points in time ( = 1, ) , right ascensions , and declinations . ... Determination of the orbit using the Gauss method of determining orbital elements based on two heliocentric positions and points in time. ...

... Categories: calibration GPDOF estimates the likely error in a calibration solution, by calculating the errors in the "Degrees-of-Freedom" (dofs) of an interferometer. This is useful for calibration of high-precision circular polarization observations. ... Finally, GPDoF calculates the std and standard error of the derived dofs, which you can use to estimate the errors in the Stokes V of a target observation. ... GPDoF estimates the std and standard error in the dofs. ...

... The HST uses an onboard model of its orbit to perform in real-time various control functions relating to spacecraft operations and observation support. ... New coefficients for the ephemeris are updated every other day, and are archived as FITS keywords for each HST observation data set. Using these coefficients,an observer can perform a variety of calibration and characterization calculations relating to the orbital position and velocity of the telescope. ...

Next: Primary Catalog Up: Observations and Analysis Previous: Source Positions . ... This energy selection allows direct comparison with previous EGRET, COS-B and SAS-2 results. ... The energy spectra shown in the catalog are taken largely from previous EGRET publications (or those currently in the publication process), which discuss the details of source identifications, time variability, and energy spectra. ... Such sources are identified in the catalog. ...

... The experience of determination of the link between radio sources and dynamical reference frames is presented. To obtain this connection we used a series of very long baseline interferometry (VLBI) observations of the spacecraft Phobos-2 and angularly nearby quasars. ... The dynamical reference frame is determined by equator and equinox of these ephemerides. ... References . ... The relative orientation of the radio and dynamical reference frames can be described by a sequence of three rotations . ...

... The accuracy of calculation of both INTERBALL spacecraft (SC) motion has been estimated at the IKI. ... The 30 days measuring intervals were used during the Tail probe (TP) orbital data treatment, and 15 days intervals - during the Auroral probe (AP) orbit determination. ... http://www.iki.rssi.ru/vprokhor/indap.htm for the Auroral probe; . http://www.iki.rssi.ru/vprokhor/indtp.htm for the Tail probe . ... http://www.iki.rssi.ru/vprokhor/ssc.htm , or http://www.iki.rssi.ru/vprokhor/amisan.htm . ...

... Based on the measurements of the Stokes parameters in the continuum and in the broad 0.6563 nm hydrogen emission line obtained with the 6-m telescope for the Seyfert galaxy Mkn 6, secular variability of the hydrogen line profile polarization was discovered; a time lag of less than 2 days between the continuum flux and the polarized continuum emission was determined which corresponds to the size of the region where the polarization of the continuum occurs, less than 0.001 pc. ...

For solar wind dials without any explanatory text, see this page . ... There are three logs, one for each condition index ( K P , Solar Wind ,and NOAA/SEC .) ... More about the solar wind's recent behavior can be found on my Current Solar Wind Conditions page. ... Other items of interest include NOAA/SEC Current Conditions , my composite current Auroral Images page, Windows on the Universe: Space Weather , and Public Outreach Index, Department of Space Physics and Astronomy, Rice University . ...

Taking into account the result by Watanabe P=2.5 days in outburst, I reconstruct old set of photographic observations being partly lost, and add some new observations. ... The periodogram calculated with the method by Lafler and Kinman is shown. ... The last periodogram indicates peaks corresponding following possible periods with the double-wave light curve: 0.4236, 0.4650, 0.5379, 0.6064, 0.7365, 0.871, 1.168, 1.5437, 2.8173, and 6.89 days. ...

... Binary orbits in the acceleration/period plane . Circular Orbits . ... We first present the equations for the period and acceleration of a pulsar in an eccentric binary system as a function of its position in the orbit. ... In Freire, Kramer & Lyne (2001) (from where most of this text and following equations are taken), we describe in more detail how circular binary orbits can be determined from the observed periods and accelerations of the pulsar. ... where is the orbital period of the binary. ...

Databases (NSDC) of the Natural Planetary Satellites. ... NSDC: Database of astrometric observations of Natural Planetary Satellites . ... They are thoroughly looking for observations in different sources, creating their owndatabases which are then mostly inaccessible to other researchers. ... In the file "content" with explications, the reference is given to the data source as well as the bibliographic reference. ... Data sources. ... Why a specific bibliographic database for Natural satellites? ...

... This task operates on event data in an event list. ... In the first two cases, the celestial coordinates of the reference point are taken respectively as the values of the RA_NOM , DEC_NOM or RA_OBJ , DEC_OBJ values in the input event file header. ... Although the OM attitude information may be more accurate, it will not be present throughout part of the observation, and as such, the default source for the attitude data should be "ahf". ...

The ESA/ESO Astronomy Exercise Series 2 . The Distance to Messier 100 as Determined by Cepheid Variable Stars . ... The small variations in distance to the individual Cepheid variable stars in the Cloud are negligible compared with the much larger distance to the SMC. ... In this way Cepheid variable stars can be used as one of the 'standard candles' in the Universe that act either as distance indicators themselves or can be used to calibrate (or set the zero point for) other distance indicators. ...

... Line ratios calculated from temporal series observations of O IV and Fe XIII spectral lines were converted to electron density, and hence electron pressure using theoretical line ratios. Little or no evidence was found to support the constant electron density assumption, and instead a constant electron pressure is found between the transition region and corona. ...

... This class is designed to be an up to date summary of the last 10-20 years of observations relevant to Cosmology. ... Theory today is bombarded by a vast array of observational data but there remains no clear and preferred model for the origin and evolution of structure in the Universe. ... The inflationary paradigm and the nature of the Dark Matter - Inflation solves a lot of problems that are inherent in the standard Big Bang Model. ... Kinds of Dark Matter and Observational Constraints . ...

... Ser. 27,21 # by adding a constant offset in m_AB. The offset is determined for the region # 5250-9200 Angstroms. ... SET .Z.UNITS = mjy SET .Z.LABEL = Fnu SET .TABLE.BANDWIDTH = 50 SET .TABLE.LAMBDA_DOUBLE = 11000 * 3050.000 2.741 3100.000 5.483 3150.000 7.639 3200.000 9.151 3250.000 10.653 3300.000 11.985 3350.000 13.154 3400.000 13.901 3450.000 13.142 3500.000 14.718 3550.000 14.992 3600.000 14.637 3650.000 15.756 3700.000 14.370 3750.000 9.787 3800 ...