... 2007 November 15 . M13: The Great Globular Cluster in Hercules . ... Explanation: M13 is modestly recognized as the Great Globular Cluster in Hercules . ... At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter, but approaching the cluster core over 100 stars would be contained in a cube just 3 light-years on a side. ... Among the distant background galaxies also visible, NGC 6207 is above and to the left of the Great Globular Cluster M13 . ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2000 November 8 . October Skylights . ... Explanation: With brilliant Venus above the western horizon at sunset and Jupiter and Saturn high in the east by early evening, November's night sky is filled with bright planets. October's sky featured bright planets as well and, triggered by the active Sun, some lovely auroral displays . ...

... MPIfR activities - GMVA Global mm-VLBI Array ( GMVA ) is doing VLBI at 3mm and 7mm wavelengths Coordinated correlated by the MPIfR Typically two observation sessions per year Phased- ALMA will possibly join GMVA observations starting in cycle-4 ( 2017) MPIfR activities - GMVA Requirement by ALMA : demonstrate that GMVA + ALMA observations can be succesfully correlated Test ...

... This cosmic hang-up has been debated over much of last century, as astronomers wondered whether this binocular-visible object is really a physically associated open cluster or a chance projection. ... Tomorrow's solstice marks the southernmost point of the Sun's annual motion through planet Earth's sky and the astronomical beginning of winter in the north. ... It's also very red, exhibiting such a remarkable spectrum of light, 19th century astronomer Angelo Secchi dubbed it La Superba. ...

... Tonight's Sky . ... The Magazine . News . 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 . ... Open cluster NGC 2818, spiral galaxy NGC 2964, and spiral galaxy NGC 2976 . ... Astronomy for Kids . ... November 2011 . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ... Astronomy Magazine . ...

... New APT ETC Features and Improvements . for ETC version delivered on November 25, 2003) . ... News and . ... HST Overview . Overview . ... For point sources, the ETC also gives an estimate of the "optimal S/N" (i.e. PSF-fitting method). A new thermal model has been implemented. The Backgrounds and extinction laws have been homogenized with those used by the ETCs of other HST instruments. ... Further information can be obtained from the help link connected to the APT ETC user interface. ...