... Such particles are called ``optically soft'', and the corresponding approximation could be named that of optically soft particles. ... For the theory based on the assumption (1), there are a set of the names: Rayleigh-Gans [ 11 ], Rayleigh-Debye [ 274 , 397 ], Rayleigh-Gans-Born [ 474 ], Rayleigh-Gans-Debye [ 78 , 144 , 409 , 410 ], Rayleigh-Gans-Rokard [ 132 ], Rayleigh-Debye-Gans (RDG) [ 100 , 462 ], Born (or the first Born) [ 56 , 135 ] approximation. ...

... How much brighter is the Sun as viewed from the planet Mercury as compared to Earth ? ... Actually, all of these questions can be answered through a very simple mathematical relationship known as the inverse square law. ... As the distance from the Sun increases the surface area of the sphere grows by the square of the distance. ... Common sense tells us that the Sun will be brighter and the inverse square law tells us how much brighter. ... gr = 0.912 G or 91.2% gravity felt at Earth's surface. ...

... The bright supernova (hereafter SN) in the galaxy NGC 4527 was first sighted by S. Knight (USA) on April 13.17UT at magnitude ~14.0v. The report of the sighting was subsequently forwarded by phone to the AAVSO. ... SN 1991T. The galaxy NGC 4527 is an Sb(s)II type galaxy with an apparent Blue magnitude of 11.32 (Shapley-Ames, 1981). ... An analysis of this event utilizing visual observations by amateurs, plus a light curve is presented.. ... THE LIGHT CURVE: . ... ISN SN 1991T web page . ...

... With enough velocity, a spacecraft can break loose from the Earth's gravity and enter an orbit around the Sun, like that of a planet. If it then orbits the Sun with the same period as the Earth--one year--it may keep a fixed position relative to Earth. ... If the distance is just right--about 4 times the distance to the Moon or 1/100 the distance to the Sun--the spacecraft, too, will need just one year to go around the Sun, and will keep its position between the Sun and the Earth. ...

... Astrophysics Group . ... VSA . ... CAT . ... The Very Small Array is a custom-built radio telescope (operating between 26-36 GHz), designed expressly to make high resolution observations of the cosmic microwave background (CMB) radiation on angular scales around and below one degree. ... The VSA has been operated in ?compact array? and ?extended array? configurations (see the technical description below) and data collected to achieve high sensitivity in both regimes have been analysed. ... 1.75 GHz)...

... 2009 March 3 . The Helix Nebula from La Silla Observatory . ... The Helix Nebula is one of brightest and closest examples of a planetary nebula , a gas cloud created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space appear from our vantage point as if we are looking down a helix . ... A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin . ... About APOD | ... NASA Official: Phillip Newman Specific rights apply . ...

Общая Астрономическая Конференция . ... Правила форума . ... Сообщения за день . ... Добро пожаловать на Общая Астрономическая Конференция. ... Форумы общей направленности . Любые вопросы от новичков (просматривают: 17) . ... Общий форум любителей астрономии (просматривают: 7) . ... Новости магазина Starshop.ru . ... Менее астрономические товары (просматривают: 1) . ... Форум исключительно для сообщений об испытаниях астрономической техники. ... Общая Астрономическая Конференция статистика . ...

Astronotes Armagh Planetarium's Stellar Blog! ... Our Galaxy . ... Stars . ... September . ... Posted on September 12, 2011 | No Comments September features yet another delightful selection of astronomical treats. ... Continue Reading.. ... 3 Comments The astronomy community is excited by the discovery of an exploding star, a supernova, in a galaxy 21 million light years away in the constellation Ursa Major. ... Posted on August 19, 2011 | ... Posted on July 8, 2011 | ... Posted on June 10, 2011 | ...

... A star was observed at different zenith distances during one night at the Engelgardt's Astronomical Observatory in the program of atmospheric extinction study at blue. ... The determination of the star's brightness was performed with the method of photon counting. ... Variable star. ... The brightness of the variable star was measured occasionally during the other nights, and moments of maximal values of brightness (15.59m) were received on nights 2­5, the 2nd table. ... JD 2452805. ...

... Meade Instruments Corporation . ... Section 3: File Menu . ... Displays the dialog to open an existing image: . ... Saves the current image as a new file name or new file type, or both. ... This can be useful to prevent having 20 or more images open at once, and saves having to close them manually. ... This is done by creating a text file with the same name as the image file. ... Note that Image Information is saved within the FITS file, so there will not be a text file to accompany these files. ...

THE RELATIVE MONTHLY MEAN SUNSPOT NUMBER ON JUNE 2011 HAS MADE Wjune =37.0, THAT GIVES FOR 24 MONTH (2010, DECEMBER) DEVELOPMENT CURRENT 24 CYCLES OF SOLAR ACTIVITY THE SMOOTHED MONTHLY MEAN SUNSPOT NUMBER W*dec. ... THE INTERNATIONAL DAILY VALUE OF RELATIVE SUNSPOT NUMBER FOR 2011, JUNE ACCORDING DATA OF 70 SOLAR OBSERVATORIES HAS MADE 1.. ... NEXT WEEK THE LEVEL OF SUNSPOT ACTIVITY IS EXPECTED TO BE LOW AND BY THE END OF THE PERIOD APPROUCH THE AVERAGE VALUE. ...

... Chandra Survey . ... Bulge Windows Survey . ... The ChaMPlane survey is being conducted at the Harvard-Smithsonian Center for Astrophysics. As a complement to our ChaMPlane survey, we have conducted a deep survey of low-extinction windows in the Galactic Bulge. ... were observed (nearly) simultaneously with Chandra and the Wide Field Camera on the Advanced Camera for Surveys (ACS) on HST. ... The Chandra and HST observations for the Bulge Window Survey were carried out from 2003 to 2005. ...

... Two such triple stars with low mass components, GJ 900 and KUI 99, have been observed during the last six years at the 6 m BTA telescope (Zelenchuk). ... Fig. ... The relative positions of the AB pair changed linearly during the period 2000­2004, showing a mean value of 48 mas/yr (Fig. ... Orbital solutions for the outer pair were proposed by Baize [1], Heintz [4] and Soderhjelm [10]. ... The apparent ellipses of the KUI 99 AC and KUI 99 AB pair are shown in Fig. ... P. Baize: Astron. Astrophys. ...

... The European HST Archive has been moved to ESA's European Space Astronomy Centre ( ESAC ), Spain, where most of ESA's Space Science Archives are located and operated from. ... The Space Telescope European Coordinating Facility (ST-ECF), jointly operated by ESA and the European Southern Observatory ( ESO ) was, until the end of 2010, the European HST science facility, supporting the European astronomy community in exploiting the research opportunities provided by the Hubble Space Telescope. ...

CCD imaging and photometry of large BCGs subsample . For many problems connected with study both group and individual properties of blue compact galaxies (BCGs), it is important to know their photometric and structure parameters. ... For the study of BCG phenomenon it is important to probe possible relations between the main physical parameters of this galaxies such as luminosity, characteristic size, gas mass, color indexes, etc. ... 10 BCGs are very compact and hard to classify. ...

... PUL2 catalog contains original absolute proper motions of 59646 stars in 149 fields with galaxies. ... Mean errors of relative proper motions in PUL2 catalog is 5.5 mas/year. ... The external mean error of one relative proper motion of a bright star of PUL2 catalog is 9 mas/year for both of coordinates. ... After issue of UCAC2 catalog, we decided to improve accuracy of proper motions, using Pul-3 coordinates (of 1950s) as the first epoch, and UCAC2 coordinates as the second epoch. ...

Links on this page are to sites that hold information on the Sun , our nearest star . ... Big Bear Solar Observatory (BBSO) , California, USA. Mauna Loa Solar Observatory (MLSO) , Hawai'i, USA. ... Space Environment Center, Current Solar Images , Boulder, Colorado, USA. ... Solar Data Analysis Center, Latest Images , at GSFC, Maryland. ... NSSDC - National Space Science Data Center, Solar Physics (at GSFC). ... NSSDC - National Space Science Data Center, Space Physics (at GSFC). Back to Links ...

... This SAS routine allows to compare real columns from two files, with absolute and relative tolerance. ... compare_realcols table =newfile(: table ) reftable=reffile(: table ) colnames= column list (abstol=tol1 reltol=tol2 operation=op) # newfile(: table ): name of the first file with table ( first by default ) # reffile(: table ): name of the second file with table ( first by default ) # column list : names of the columns to be compared (separated by a blank) # tol1 : absolute ...

The revision of the MASS/DIMM star catalogue N. Shatsky, V. Kornilov March 16, 2008 Abstract The compilation of the (updated) version of the MASS (MASS/DIMM) device target catalogue is described. ... Then the list was cleaned according to following criteria: I. Remove stars too faint for a MASS device. ... Here the color equation of the Sternb erg device was taken: M AS S mag = V mag + 0.45 (B - V ); stars with M AS S mag > 3.2 were removed. ... This was made based on the GCVS4.2 catalogue data. ...

Moscow Astronomical Plate Archives: . Contents, Digitization, Current and Possible Applications . ... We describe the astronomical plate archives in Moscow and Zvenigorod and the existing digitization projects. ... 2 The Plate Archive of the Sternberg Institute . The contents of the most important Moscow astronomical plate archive, that of the Sternberg Astronomical Institute, was briefly presented in Shugarov et al. [1] in 1999. ... THE MOSCOW PLATE COLLECTION (STERNBERG INSTITUTE) . ...