... The Coma Cluster of Galaxies . ... Deep inside Centaurus A, the closest active galaxy to Earth, lies ... another galaxy! ... At least that was the conventional wisdom when it was first realized that the space between the stars is filled with hydrogen, a strong absorber of extreme ultraviolet light. ... Is the Moon larger when near the horizon? ... The result, shown above, is the most complete sky map of the most common visible light emitted from the most abundant element in our Galaxy: hydrogen. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. December 7, 1997 . A Distant Cluster of Galaxies . ... Explanation: In this 1994 Hubble Space Telescope photograph , every bright object is a galaxy . ... Photos like this indicate that clusters in the past contained a higher fraction of spirals than do nearby clusters which are usually dominated by elliptical galaxies . ... About APOD > . ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

Astronotes Armagh Planetarium's Stellar Blog! ... Our Galaxy . ... Stars . ... Space Flight . ... A galaxy is born: This artist's impression shows a young galaxy, about two billion years after the Big Bang, accreting material from the surrounding hydrogen and helium gas and forming many young stars. ... Galaxies, distant from us in space and time, have been in the news recently. ... Astronomers at the European Southern Observatory have observed another process which helped primordial galaxies grow. ...

... Science User Portal . ... Galaxies . ... Star Clusters . ... Stars@ESO . ... New observations from ESOтАЩs Very Large Telescope have, for the first time, provided direct evidence that young galaxies can grow by sucking in the cool gas around them and using it as fuel for the formation of many new stars. ... This allows them to make a map that shows the quantity of heavy elements present in different parts of a galaxy and also determine where in the galaxy star formation is occurring most vigorously....

Discover the cosmos! ... December 6, 1999 . M83: The Southern Pinwheel Galaxy from VLT . ... Explanation: M83 is one of the closest and brightest spiral galaxies on the sky. Visible with binoculars in the constellation of Hydra , majestic spiral arms have prompted its nickname as the Southern Pinwheel. Although discovered 250 years ago, only in this century was it appreciated that M83 was not a gas cloud but a barred spiral galaxy much like our own Milky Way Galaxy . ... About APOD > . ...

... About ATMoB . ... The Observing Committee is starting an Observing Awards Program to promote observing among the membership of the Amateur Telescope Makers of Boston. ... Participant must be a current member of the Amateur Telescope Makers of Boston . ... To qualify for your Observing Award Certificate, turn in your worksheet and drawings to an ATMoB Observing Committee member or observing@atmob.org . ... This Excel sheet has useful macros. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...

... These Frontier Fields will combine the power of HST with the natural gravitational telescopes of high-magnification clusters of galaxies. ... We are soliciting gravitational lensing maps for the last four Hubble Frontier Fields clusters (MACSJ0717.5+3745, MACSJ1149.5+2223, AbellS1063, and Abell 370) based upon the exceptionally deep HST FF imaging and other new ancillary data. ... For the full set of proposal instructions and requirements, see the FY16 Frontier Fields Lensing Map Call for Proposals....

... 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....

... The measurements extend to a lower 1.5 GHz limit of 1.0 mJy and comprise a complete sample with 1.5-GHz flux density 2.5 S1.5 J/AuJPh/47/145 VLA Survey of Rich Clusters of Galaxies II (Slee+, 1994) J/AuJPh/49/977 VLA Survey of Rich Clusters of Galaxies III (Slee+, 1996) ================================================================================ A VLA Survey of Rich Clusters of Galaxies II. ... Note (3): An elliptical Gaussian was fitted to the source. ...

... This paper ( Burke et al. 2003 ) describes the creation of one such catalogue - the Southern Serendipitous High-redshift Archival ROSAT Cluster (SHARC) survey - which covers an area of 17.7 deg 2 and consists of 32 clusters with redshifts between 0.05 and 0.7 and X-ray luminosities between 7 x 10 42 and 4 x 10 44 erg/s: the high-redshift subsample contains 16 clusters with = 0.3 and X-ray luminosities greater than 2 x 10 43 erg/s (luminosities are quoted for the 0.5 - 2.0 keV energy band). ... 1997 ...