... 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....

... 27.07.2011 . ... Comet Garradd was discovered two years ago by Gordon Garradd in Australia , and is currently visible through a small telescope at visual magnitude nine. Officially designated C/2009 P1 (Garradd), the comet will likely continue to brighten, with recent projections placing it at peak magnitude six or seven in February 2012, just below naked eye visibility. ... July 2011 . ... 2011 2012 . ... Publications with keywords: comet - Solar System . ... Comet Lovejoy over The Great Wall . ...

As noted earlier Kristian Birkeland, reporting in 1903 on his expeditions to the auroral zone, proposed that magnetic disturbances accompanying the aurora were caused by large electric currents flowing down the length of auroral formations. ... Some scientists disagreed with Birkeland and claimed the electrojets did not connect to space but instead their entire circuit lay inside the ionosphere, like that of other ionospheric currents known at the time, believed to be caused by atmospheric tides. ...

... The choice of which type of electricity is called "positive" and which "negative" was made around 1750 by Ben Franklin, early American scientist and man of many talents (the stamp on the left commemorates his role as first US postmaster--and colonial postmaster before that). ... Franklin knew of two types of electric charge, depending on the material one rubbed. ... Later, when electric batteries were discovered, scientists naturally assigned the direction of the flow of current to be from (+) to (-...

Подписка на рассылку обзоров astro-ph на Subscribe.Ru . ... Предыдущий выпуск (N335) . ... Обсудить на форуме Scientific.RU . ... Подписка на рассылку обзоров на Subscribe.Ru . Обзоры препринтов astro-ph . ... Собственно обзоры препринтов. ... Ранее обзоры также были на Астронете и на Scientific.Ru . ... АНКи доступны на Астронете , а с 2006 по 2008 г. также на сайте Элементы.Ру . ... Ранее они также размещались на сайте Астронет и в архиве моих обозрений (кодировка KOI8) на сайте Scientific.Ru . ...

... Users . ... AAS 225 . ... This particular part of the analysis has been disabled since the code is struggling to cope with the number of users seen this year, in particular the large contingent of people who have re-tweeted NASA. ... The links between the accounts identify those users who have mentioned another user in a tweet, using the @name syntax; the line widths increase based on the number of mentions but given that the graph is ever-so-slightly crowded this isn't that useful at this time. ...

... November 29, 1998 . Arecibo: The Largest Telescope . ... Explanation: The Arecibo radio telescope is currently the largest single-dish telescope in the world. ... The Arecibo telescope has been used for many astronomical research projects , including searches and studies of pulsars , and mapping atomic and molecular gas in the Galaxy and the universe . ... About APOD > . ... NASA Technical Rep.: ... A service of: LHEA at NASA / GSFC . ...

... Tonight's Sky . ... The Magazine . ... Observing . ... Magazine . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... 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 . ... large (8 inches or larger) . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ... Astronomy Magazine . ...

... Corporate Partners Rock Our Cosmos! Current Partners . ... In addition to Sky & Telescope and SkyandTelescope.com, the comany publishes Night Sky, a bimonthly magazine for beginning astronomers, an annual magazine called SkyWatch, an annual magazine called Beautiful Universe, as well as books, star atlases, posters, prints, globes, and other fine astronomy products. ... We thank our Corporate Affiliates for their annual investment in partnering with the ASP to improve astronomy education. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2000 February 28 . The Sombrero Galaxy from VLT . ... FORS1 , VLT ANTU , ESO . ... Reasons include the Sombrero '