... Credit: N. A. Sharp , REU program / NOAO / AURA / NSF Explanation: What is causing the unusual flashes behind globular cluster M22? ... M22's center was recently imaged repeatedly by the high resolution Hubble Space Telescope . Behind M22 are many more stars near the center of our Galaxy . Unexpectedly, several stars near the Galactic center -- well behind M22 -- appeared to nearly double in brightness and return to normal within 20 hours. ... Globular Cluster M22 from CFHT . ...

... 2001 July 3 . Unusual Flashes Toward Globular Cluster M22 . ... Explanation: What is causing the unusual flashes behind globular cluster M22? This teeming ball of stars is the brightest globular cluster visible from Earth's northern hemisphere. M22 , shown in full in the inset, spans about 50 light-years and lies 8,500 light-years away toward the constellation of Sagittarius . ... Behind M22 are many more stars near the center of our Galaxy . ... About APOD | ...

Astronotes Armagh Planetarium's Stellar Blog! ... Comets and Asteroids . ... Image credit:ESO/J.Emerson/VISTA. ... However others are less pessimistic and it has even been claimed that the mysterious ?Wow! signal? received in 1977 originated from the direction M55.б  Sadly, this still unexplained pulse of radio energy originated from a location rather to the northwest of M55 so I doubt if the source was this cluster (if indeed the signal was genuinely of extraterrestrial origin). ... Mysterious Wow! ...

... BLUE STRAGGLER STARS are unusually hot and bright stars found in the cores of ancient star clusters known as globulars. ... BACKGROUND (from wikipedia): Blue straggler stars are stars in open or globular clusters that are hotter and bluer than other cluster stars having the same luminosity. ... There is evidence in favor of this view, notably that blue straggler stars appear to be much more common in dense regions of clusters, especially in the cores of globular clusters. ...

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... 2000 August 4 . M15: Dense Globular Star Cluster . ... In fact, only 40,000 light-years away in the constellation Pegasus, M15 is one of the most densely packed globular star clusters in our Milky Way Galaxy. This stunning Hubble Space Telescope image of M15 shows thousands of individual stars across the central 10 or so light-years of the cluster, also cataloged as NGC 7078. ... Globular star clusters harbor from a hundred thousand up to a million stars and roam the Milky Way halo. ...

You Can Make Stellar Images Brighter . Articles | ... A few months ago I wrote an article titled "You Can’t Make Them Brighter". So why am I now writing that you can make them brighter. ... The image of a focused star is actually a small disk called the Airy disk, named after the 19 th century scientist Sir George Airy. ... For a given aperture, a smaller Airy disk means that the light is focused to a smaller disk and is therefore brighter. ... www.astronomy.net . About Astronomy Net | ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Three sixth-form students from St Patrick's Grammar School, Armagh , used the Faulkes Telescope South in Australia in April to observe and measure HW Virginis , an unusual "binary" or double star system suspected to host one or two extrasolar planets orbiting the central stellar pair. ... Armagh Observatory and associated researchers hope to develop this work to look for further evidence of planet-hosting binary star...

... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

... Ultraluminous X-ray sources (ULXs) are located in external galaxies, their X-ray luminosities (10 39 - 10 41 erg/s) are thousand times greater than those of brightest black holes in the Galaxy. ULXs may be supercritical accretion disks around black holes of stellar masses (~10 Solar masses) like that in SS433, or they may be a hypothetical intermediate-mass black holes (hundreds - thousands Solar masses) with standard accretion disks. ... 2) The ULX progenitors were ejected from the star clusters. ...

... The Pleiades star cluster, also known as the Seven Sisters and Messier 45, is a conspicuous object in the night sky with a prominent place in ancient mythology . ... The stars in the Pleiades are thought to have formed together around 100 million years ago, making them 1/50th the age of our sun, and they lie some 130 parsecs (425 light years ) away. ... Data for these stars are listed in a table below. ... Yes . ... WEBDA Pleiades cluster data . ... M45: The Pleiades Star Cluster (2007 November 18) ...

... Bad Astronomy . ... Bitesize Astronomy . ... The next step up are true clusters, called open clusters . Open clusters (sometimes misleadingly called "galactic clusters") are groups of stars ranging in size from a few dozen stars up to tens of thousands. ... The youngest is about 1 or 2 million years old, while the oldest is about 6 or 7 billion years, making it just older than our own solar system. ... So by looking at the stars in the cluster we can tell pretty well how old they are. ...

... A faint, dusty rose of the northern sky, emission nebula IC 410 lies about 12,000 light-years away in the constellation Auriga. The cloud of glowing hydrogen gas is over 100 light-years across, sculpted by stellar winds and radiation from embedded open star cluster NGC 1893. ... These "tadpoles" (seen just below center) are regions of denser, cooler gas, and more slowly resist the erosive radiation from the hot stars. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...

Name Last modified Size Description . Parent Directory - coma_cluster_B_00014dfw.fits 2012-04-11 21:51 64M coma_cluster_R_00012dfw.fits 2012-04-11 22:40 64M coma_cluster_V_00013dfw.fits 2012-04-11 22:36 64M coma_rgb_log_100_20120410.jpg 2012-04-11 23:10 288K . Apache/2.4.6 (Linux/SUSE) Server at www.astro.louisville.edu Port 80

... Another shock for the Bullet cluster . ... With Australia Telescope Compact Array (ATCA) observations we ( Shimwell et al. 2015 ) detect a highly elongated Mpc-scale diffuse radio source on the eastern periphery of the Bullet cluster 1E 0657-55.8, which we argue has the positional, spectral and polarimetric characteristics of a radio relic. ... The image to the left shows the X-ray emission of the Bullet cluster (colour) overlaid with the ATCA radio continuum emission (green contours). ...

... IAU planet classification Observing with a Telescope Large Scale Structure The observables: Local Group (size 1 Mpc) Virgo cluster (size 2+ Mpc) Virgo supercluster (size ~33 Mpc) Voids (size ~ 10-150 Mpc), Walls and sheets, aka filaments (size ~ 50-80+ Mpc) 1 parsec The nearest star is 1.2 parsecs away (Proxima Centuri). ... Virgo supercluster Voids, Sheets Filaments The Virgo Cluster is a cluster of galaxies at a distance of about 18.0 Mpc away in the constellation Virgo. ...

... 320, P L45-L48 (1997). Abstract . ... 320, P L49-L52 (1997). ... 320, P L53-L56 (1997). ... 320, P L57-L59 (1997). ... 320, P 685-695 (1997). ... 320, P 696-704 (1997). ... 320, P 705-716 (1997). ... 320, P 717-730 (1997). ... 320, P 731-745 (1997). ... 320, P 746-756 (1997). ... 320, P 757-775 (1997). ... 320, P 776-782 (1997). ... 320, P 783-786 (1997). ... 320, P 787-790 (1997). ... 320, P 791-798 (1997). ... 320, P 799-810 (1997). ... 320, P 811-822 (1997). ... helpdesk@link.springer.de . ...

In autumn 1994, two groups of astronomers announced that they had discovered Cepheid variable stars in a distant cluster of galaxies. ... As the term suggests, variable stars change in brightness over time. ... Variable stars are an ideal way to get high-school students doing real science, with real data, from the real sky. ... a sky chart to find the stars . ... Students can use the nearby stars to estimate the magnitude of Delta. ... Locate the star Delta in Cepheus and estimate its brightness . ...

The apparent path of the Sun across the sky. ... The path of the Sun across the celestial sphere is very close to that of the planets and the moon. ... In one year, as the Earth completes a full circuit around the Sun (drawing above), the Earth-Sun line and its continuation past Earth sweep the entire plane. ... Since the Sun and Earth are in the plane of the ecliptic, the line is automatically in that plane too; if the moon is also on the same line, it must be in the plane of the ecliptic as well. ...

ADC CATALOG HOLDINGS SHORT TITLE LIST March 29, 2002 (adapted from ftp://adc.gsfc.nasa.gov/pub/adc/archives/catalogs/key) Category 1: Astrometric and Positional Data - March 29, 2002 1090 Positions of 502 Stars in Pleiades Region (Eichhorn+ 1970) 1107A Washington Cat Visual Double Stars 1984.0 (Worley, Douglass 1984) 1131A SAO Star ...