... Stars . ... Cepheid variable stars have been known since the 18th century. ... Regularly brightening to a peak over days, weeks or months before fading these variable stars were remarkable curiosities to astronomers in past centuries.€а The term Cepheid is taken from the star Delta Cephei in the constellation of Cepheus, which was identified as variable€а in 1784 by the teenaged prodigy John Goodricke (1764-96). ... Tweets that mention Cepheids: Inconstant Stars which break the rules | ...

A STUDY OF THE FRAGMENT DISPERSAL AND TRAJECTORY OF THE SAYH AL UHAYMIR 001 METEORITE SHOWER. ... We obtained hundreds of GPS find locations, analyzed the fragment distribution, and developed a model of the meteorite's trajectory. ... More than 2670 samples weighing more than 450 kg have been collected. ... Increasing fragment mass along track indicated a flight direction of 233o. The fragments' mass distribution was used to model the meteorite trajectory. ...

... The accuracy of the RESIK measurements allows photospheric and coronal abundance sets, important for the free­bound continuum, to be discriminated. ... The FB emission depends on the set of abundances used in the calculations, a coronal set (Feldman 1992; Fludra & Schmelz 1999) giving rise to greater emission than a photospheric set (Grevesse et al. ... Right panel: continuum fluxes compared for coronal (Feldman 1992) and photospheric (Grevesse et al. 2007) abundances for Te = 15 MK. ...

A&A 467, 991­1001 (2007) DOI: 10.1051/0004-6361:20066758 c ESO 2007 Astronomy & Astrophysics Metallicity and age gradients in round elliptical galaxies M. Baes1 , O. K. Sil'chenko2,3 ,A.V. Moiseev4 , and E. A. Manakova2 1 2 3 4 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, 9000 Gent, Belgium Sternberg Astronomical Institute, University av. ... We probe the stellar population age and metallicity distributions in nearby elliptical galaxies over the largest extension to date. ...

MATSYM - symbolic matrix processor . ... To use the program you will need a MAT file (liked CIR file: "User manual for CIRSYM program") of your system. ... In first string of MAT file enter any text you want to be the title of your system. ... Starting from string 2 (if is not comments - "*") enter the system element name, incident row and column and, optionally, its value. ... To generate a solution, run MATSYM.exe and enter "system_file_name.CIR" or click on the "ENTER" (in "MAT" case). ...

... First Contact Moon begins to move over Sun from West Starts at ~5:44:45 AM (about 10 minutes after sunrise) Must observe sun with filter! Good time to check and adjust mount tracking and alignment Watch for sunspots 6/21/ 2001 - Zambia ( Mario Motta ) First Contact Crescent images of Sun Natural pin-holes such as leaves on trees Pin-holes in cardboard Mario Motta Watch sky and environment Gradually darkens Temperature drops 8/11/1999 Hungary (Eric Pauer) ~1 min Before Second ...

... A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. ... The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program. he introduction of artificial light has caused an unprecedented disruption to the nighttime environment over large areas of the Earth. ... Data processing...

... For reliable estimation of the accuracy of asteroid CCD observations we usually consider from ten or more various NUMBERED MINOR PLANETS (NMPs) observed during several nigths per month (more then 50 positions). ... They can be considered as an indicator of accuracy of the CCD positional observations with given MPC code. ... For any NUMBERED minor planet the (O-C) values must be zero if the errors of observations and the errors of its theory are absent. ...

... ARTICLE: The Adventurous Search For The Astronomical Unit . ... Kepler himself had suggested to use the rare occasions of Venus transiting (crossing) the solar disk to measure our distance to the planet. ... Due to the orbital inclination of Venus against the ecliptic of 3.5°, a Venus transit is so rare that it happens only at intervals of 121.5 years, 8 years, 105.5 years, 8 years and so on. ... Crabtree witnessing the transit of Venus 1639 . ... Transits of Venus - The Quest for the Solar Parallax...

... VaST is a software tool for finding variable objects on a series of astronomical images. ... VaST performs object detection and aperture photometry using SExtractor on each image, cross-matches lists of detected stars, performs magnitude calibration with respect to the first (reference) image and constructs a lightcurve for each object. ... VaST FITS image viewer ./pgfv . ... Part I" PZP, vol. ... K. V. Sokolovsky, S. A. Korotkiy; "New Variable Stars Discovered by the NMW Survey" PZP, vol. ...