... In collaborative work with David Garc?a Alvarez (an Observatory PhD student now at Harvard) and John Butler, an extensive study of the RS CVn binary HR1099 was completed leading to two papers; the first on Doppler imaging and the second on flare activity. Spectra for the Doppler imaging were taken at two different sites, Kitt Peak National Observatory (KPNO), Arizona, and Mount Stromlo Observatory (MSO), Australia, during the 1998 MUltiSIte COntinuous Spectroscopic (MUSICOS) campaign. ...

... It is found that the correlation coefficients between these two parameters calculated separately inside and outside the sunspot formation zone ±30 have cyclic variation and occur in anti-phase. This suggests different mechanisms of formation of the corona in the fields of small, medium, and large scales. ... The relationship between the coronal green line brightness (CGLB) and the magnetic field strength (MFS) has been investigated by constructing the corresponding synoptic maps for the 1977-2001. ...

... In this activity, students will observe that the faintest stars which they can see in the sky are affected by many things: the adaptation of their eyes to the dark, the presence of clouds or haze, the time of year, and the presence of light pollution. General Information . ... After completing this activity, students should have a better understanding of the practical processes for dealing with the light pollution problem and with other environmental and societal issues. << previous page | ...

... 2002 March 7 . Comet Ikeya-Zhang Brightens . ... Explanation: In the last week , Comet Ikeya-Zhang has become bright enough to be just visible to the unaided eye. Based on its present activity, observers are optimistic that Ikeya-Zhang will become substantially brighter. This composite color image from March 3rd, captured with a wide-field telescope, shows this active comet's bright, condensed coma and a delightful array of subtle structures in its developing tail. ... About APOD | ...

... It provides long range planning information to the scheduling team; it provides bright object, timing, and orientation information to the observation planning team; and it provides graphical description of the observations and their constraints. ... The GUI graphically displays the constraints that are computed by Spike and stored in the description files and in the database. ... BOAS processes all bright objects that have entered the database since the last time BOAS was run. ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

The night sky brightness, together with number of clear nights, seeing, transparency, photometric stability and humidity, are some of the most important parameters that qualify a site for front-line ground--based astronomy. ... Night sky at ESO-Paranal (Chile). ... Night sky brightness data . ... UBVRI night sky brightness at ESO-Paranal during sunspot maximum (A 2003, PDF) . ... The Dancing Sky: six years of night sky observations at Cerro Paranal (Starlight 2007 conference proceedings, PDF) . ...

... The earliest X--ray observations were carried out in the mid--1970s. X--ray luminosities of order L erg/sec were detected in the 2-11 keV range in the direction of the Orion star forming region. ... These observations showed that the O and B stars were the brightest X--ray sources, and that TTs were also associated with emission. Feigelson and Kriss (1981) showed that some of the X--ray sources were associated with PMS stars which had not been previously detected which H surveys. ...

Proposal Identification No.: ... Proposal Type: General Category: Sub-Category: Observation Category: Total Time Requested: Minimum Useful Time: Prop osal Title: Regular Astronomy Spectroscopy Solar System 15 Hours 1 hour Arecibo OH Observations of Comet C/2013 US10 Catalina, December 2015- January 2016 ABSTRACT: Comet C/2013 US10 Catalina is a long-period comet expected to be very bright and observable at Arecibo from January 2015. ...

... Other Characteristics of the Sun: Variability of Rotation, Magnetism, Chemical Structure, Planetary System. ... Methods of Solar Magnetic Fields Measuring: Visual, Photografic, Photoelectric. ... Empiric Datas of Magnetic Fields in Photosphere, Chromosphere and Corona. ... Characteristics of Magnetic Field in Balanced Force Tubes by Potential and Forceless Field. ... Phenomenons in Active Region (Magnetic Field, Spots, Torches, Solar Prominences, Flares, Discharges. ... Magnetic Fields in Flares. ...

This page is devoted to information on Supernova 1999gn in NGC 4303 (= M61 ) Basic information on this SN, including the last reported brightness, on this Supernova can be found on the main supernova page. Information on the original web pages for many of these images can be found on the Supernova links web page. ... SEDS has a Supernova 1999gn page . ... Seiichi Yoshida has a 1999gn page . ... Kopernik 's M61 and supernova 1999gn page . ... vsnet-alert 3835 ] SN 1999gn in NGC 4303 = Messier 61 . ...

... 4.01.2005 . ... Since we are stuck inside, and since opaque dust truncates our view in visible light , nobody knows for sure. ... In the Milky Way's center is a very bright core region centered on a large black hole . The Milky Way 's bright central bulge is now thought to be an asymmetrical bar of relatively old and red stars. ... News: APOD editor to speak in January in New York . January . ... Publications with keywords: Milky Way - stars . Publications with words: Milky Way - stars . ...

... 38 CONTENTS Karachentsev I.D., Kopylov A.I., Kopylova F. G. Distance moduli in M 101 group from brightest stars .. Tikhonov N.A., Karachentsev I.D. Maffei 2, a nearby galaxy shielded by the Milky Way.. ... Zhuravkov A.V. , Bartolini C., Guarnieri A., Piccioni A., Zampieri G. Optical behaviour of GRO J0422+32 in different brightness levels ............................................................................. telescope .. ... Cas OB5 .. ... Instrumental facilities of the 6 m telescope .. ...

Quasar VLBI network observatories as co-location sites A. Ipatov, I. Gayazov, S. Smolentsev Institute of Applied Astronomy, Saint Petersburg, Russia ... supposes: 1. installation of different observational techniques at sites (co-location) 2. combined processing of different types of observations (collocation) IAA activity in space geodesy · Quasar VLBI network : ­ VLBI observations ­ GPS /GLONASS observations ­ DORIS ( ...

Observational data on solar activity is a basement for investigation of processes that take place on the Sun and interplanetary space, with data of long-term observations being of special importance. ... Subsection "Sunspot groups" is the catalogue of all sunspot groups that were observed in the given year. ... For every day of observation of the group the area of the group, the area of the largest spot (both areas - in millionths of solar hemisphere) and number of spots in the group are presented. ...

Next: Tsys scaling Up: Calibration Previous: Calibration . RPFITS files to not contain any information as to whether the telescope calibration was in units of Kelvin or Janskys. On reading the data a default value is set depending on the telescope and frequency of observation. ... ASAP> scans = scantable(('2004-11-23_1841-P484.rpf', unit='Jy') # Or in two steps ASAP> scans = scantable(('2004-11-23_1841-P484.rpf') ASAP> scans.set_fluxunit('Jy) . ...

... BTA and RATAN-600 are largest optical and radio telescopes in Russia. ... Antenna of RATAN radio telescope consist of 576-m circle of 895 elements (2 x 11.5 m), which could use as four independent sectors (225 elements) of that reflector (named: North, South, West and East). Four different feed-cabines (N1,2,3,5) with secondary mirrors could simulteniously collect radio emission from these four sectors and be used in programs of Continuum , Spectral and Solar observations. ...

... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...

. This visible-light image from the Hubble Space Telescope shows the vicinity of the star Fomalhaut, including the location of its dust ring and disputed planet, Fomalhaut b. A coronagraphic mask helped dim the star's brightness. This view combines two 2006 observations that were taken with masks of different sizes (1.8 and 3 arcseconds). // Credit: NASA/ESA/T. Currie, U. Toronto

... Dept. for Astrometry & Space Geodynamics . ... Dept. for Physics of Stars&Galaxies . ... Dept. for Physics of Planetary Systems . ... Science . ... All Pages . ... Research of the stars with planets which pass apparent star disk (transiting exoplanets). The transit method based on a detection star brightness decrease during a passing of planet in front of its disk. Observed brightness system decries when planet pass star disk and its volume depend of the relative sizes star and planet. ...