... Shadows of Saturn at Equinox . ... Unusual shadows and dark rings appeared around Saturn near its equinox last month. At that time -- early August -- Saturn's ring plane pointed directly at the Sun. ... Open Cluster M25 . ... Many stars like our Sun were formed in open clusters. ... The stars in this cluster all formed together about 90 million years ago. The bright young stars in M25 appear blue. ... Known as an extremophile, bacteria such as D. NGC 7771 Galaxy Group . ... Equinox at Saturn . ...

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Stellar Clusters are very useful laboratories for empirically studying stellar evolution. ... All cluster stars are at the same distance . All cluster stars have the same physical age . ... CM diagram Young Cluster In this case we see the Main Sequence fully represented. The blue dots represent massive stars with short main sequence lifetimes. ... Thus, identifying the most massive star which is still on the main sequence is an effective means of determining the age of a stellar cluster. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... Editor's choices for the most educational Astronomy Pictures of the Day about clusters of galaxies: . APOD: 2006 March 21 - The Coma Cluster of Galaxies . ... APOD: 2005 November 22 - A Galactic Collision in Cluster Abell 1185 . ... A prominent example occurs on the left of the above image of the rich cluster of galaxies Abell 1185. ... Recent observations of Abell 1185 have found unusual globular clusters of stars that appear to belong only to the galaxy cluster and not to any individual galaxy. ...

ST ScI Preprint #1362 . ... However, the radial extents of some of the very young clusters (ages <10 Myr) are much larger than those of old globular clusters (e.g., the outer radius of Knot S exceeds 450 pc). ... Star clusters around the edge of the dust overlap region appear to be the youngest, with ages 5 Myr, while clusters in the Western Loop appear to be 5-10 Myr old. ... A handful of old globular clusters from the progenitor galaxies are also identified. ...

... Structure of Data . ... Catalog . ... The SAI OCL Catalog site provides several VO-enabled modes of operation: . VO-enabled catalog data analysis from a browser . ... Endpoint URL is http://ocl.sai.msu.ru/catalog/conesearch/ . ... VO-enabled catalog analysis from a browser . Presently, this recipe works with Firefox (Windows, MacOS, Linux), Internet Explorer (Windows) and Opera (Windows) browsers with Java plugin 1.6 installed. ... Main TOPCAT window with SAI OCL catalog loaded will appear. ...

... Neutral and Ionised Hydrogen in NGC 4214 V. J. McIntyre1,2 1 2 Physics Department, University of Wollongong, Wollongong, NSW 2522, Australia Astrophysics Department, University of Sydney, NSW 2006, Australia vjm@physics.usyd.edu.au Abstract: It is not clear at present how the diffuse ionised gas (DIG) component in galaxies is ionised. ... How porous the ISM must be depends on the (unknown) location of the ionised emission relative to the disk. ... 1996). ... Local H I surface density is 2в1021 cm-3 ...

... Primordial theory review : Dick Bond . Defects and the CMB review : Andy Albrecht . ... Gravitational wave contribution to CMB anisotropies : V.B. Lukash and E.V. Mikheeva . C_l from cosmic strings : Lloyd Knox . Some aspects of CMB anisotropies induced from topological defects : Mairi Sakellariadou . ... CMB anisotropies from scaling sources : Ruth Durrer . ... SZ observations I : Sarah Church . ... Holes in the microwave sky? ... Detecting cosmic strings in the CMB : James Robinson . ...

... 1st Announcement IAU Symposium 312 Star Clusters and Black Holes Across Cosmic Time, Beijing, China, Aug. 25-29, 2014 . ... SUBJECT: 1st Announcement IAU Symposium 312 Star Clusters and Black Holes Across Cosmic Time, Beijing, China, Aug. 25-29, 2014 . ... which will be held in Beijing, P.R. China, from August 25-29, 2014, hosted by Chinese Academy of Sciences . ... China), . ... 1st Announcement IAU Symposium 312 Star Clusters and Black Holes Across Cosmic Time, Beijing, China, Aug. ...

Title: A New Model of the Gravitational Lens 0957+561 and a Limit on the Hubble Constant . Authors: Norman A. Grogin , Ramesh Narayan (Harvard Univ.) ... Title: ROSAT/PSPC observation of the distant cluster CL0939+472 . ... Title: Interaction in the Bimodal Galaxy Cluster A3528 . ... Title: Cosmological Implications of Galaxy Cluster Evolution . ... Title: Galaxy Cluster Virial Masses and Omega . ... Matches 201 to 222 from a total of 222 matches for the search pattern galaxy cluster . ...

ATMoB "Open Cluster Observing Award " Guidelines Purpose: To promote observing among the membership of the Amateur Telescope Makers of Boston through participation in the Open Clusters Observing Awards program. Introduction: This awards program is oriented towards visually observing open clusters above magnitude 9.9. ... It turns out that a very unprejudiced and convenient method to dermine the limiting magnitude is to count the number of visible stars in certain areas on the sky. ...

... ESO, the European Southern Observatory . ... ESO . ... Galaxy Clusters . ... Star Clusters . ... Video News Releases . ... Stars@ESO . New on eso.org . ... This video sequence shows a comparison of the view of the newly discovered globular cluster VVV CL001 in visible and infrared light. The infrared view, from the VISTA telescope, shows the new cluster very clearly for the first time and allows many of the component stars to be studied. ... Milky Way : Star : Grouping : Cluster : Globular . ...

... The large body of near infrared observations presented in Testi et al. (1997; 1998) are analysed with the aim of characterizing the young stellar clusters surrounding Herbig Ae/Be stars. The results confirm the tendency of early Be stars to be surrounded by dense clusters of lower mass "companions", while Ae stars are never found to be associated with conspicuous groups. ... Only the most massive stars (10-20Msun) are found to be associated with dense (10^3 pc^-3) stellar clusters. ...

Astronomy suffers from the `Static Illusion' - because astronomical changes usually occur over intervals much longer than a human lifetime they appear static. This illusion affects our understanding of how astronomical objects work. ... Observations at the 1/10th arcsecond level with HST and near-infrared adaptive optics on ground based telescopes are beginning to create movies of `astronomy in motion'. ... Proto-star HH-30 expanding jet HST.. Young binary, XZ Tau, expanding `bubbles' HST.. ...

Results from 6m telescope observations of globular clusters in dwarf galaxies Sharina M. We consider properties of globular clusters in dwarf galaxies observed with the multi-slit unit of the SCORPIO spectrograph at the SAO 6m telescope. ... Studying GCs in dwarf galaxies at the faintest end of the galaxy luminosity function provides valuable information for a better understanding of galaxy evolution and evolutionary connection between globular clusters and nuclei of galaxies. ...

The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda II . This paper has been accepted by the Astronomical Journal for the January 2004 issue. Download PDF or GZip'd postscript version. ... Globular Clusters and Dwarf Galaxies . ... This paper has now been published in the Astronomical Journal, Volume 124, page 332 (2002). ... This paper has appeared in the Proceedings of IAU Symposium 207 ``Extragalactic Star Clusters'', eds D. Geisler, E. Grebel and D. Minniti, p. 83 (2002). ...

... In 1930, Trumpler noticed that linear diameters (LD) of open clusters increase with distance (D) from the Sun. ... Since that time, the interstellar absorption has become one of the best studied factor in astrophysics, and we may hope that current OCL distance scales are free from this LD-D correlation. To verify if this is the case we have chosen several modern OCL distance scales and test them with the same clusters and the same angular diameters that Trumpler had used back in 1930. ...

. During 10 years, five high-energy cosmic rays (plotted as orange asterisks) came from one small part of the sky near the star Merak in the Big Dipper. Astrophysicists suspect their source is a merging pair of galaxy clusters (blue). Progressively more distant galaxy clusters appear in light blue, green, and red, while the gray shading shows the positional error for each of the five cosmic-ray detections. G. R. Farrar, A. A. Berlind, D. W. Hogg (New York University)

Astronotes Armagh Planetarium's Stellar Blog! ... Milky Way . Stars . ... This dramatic image depicts Omega Centauri, one of 200 or so globular clusters orbiting our Milky Way galaxy. ... Swarms of tightly packed stars, numbering in the thousands to low millions, globular clusters are cosmic fossils, relics of the early times of our galaxy. Omega Centauri may actually be the core of a smaller galaxy ripped apart and assimilated by our own Milky Way in the distant past. ...