Astronomy Picture Of the Day (APOD)Surprising Comet ISON
After failing to appear for Sun staring spacecraft at perihelion, its harrowing closest approach to the Sun, sungrazing Comet ISON was presumed lost. But ISON surprised observers yesterday as material still traveling along the comet's trajectory became visible and even developed an extensive fan-shaped dust tail.
Comet ISON Before and After
Sungrazing Comet ISON reached perihelion, its closest approach to the Sun, yesterday, November 28, at 18:45 UT. The comet passed just over 1 million kilometers above the solar surface, a distance less than the diameter of the Sun.
NGC 1999: South of Orion
South of the large star-forming region known as the Orion Nebula, lies bright blue reflection nebula NGC 1999. At the edge of the Orion molecular cloud complex some 1,500 light-years distant, NGC 1999's illumination is provided by the embedded variable star V380 Orionis.
Comet ISON Rising
Will Comet ISON survive tomorrow's close encounter with the Sun? Approaching to within a solar diameter of the Sun's surface, the fate of one of the most unusual comets of modern times will finally be determined.
Cap Cloud over the Sierra Nevadas
One might say this was a bell weather day for the Sierra Nevada mountains. In January, just as the Sun was setting above the district of AlbayzМn in Grenada, Spain, a huge cloud appeared as a bell capping the Veleta peak.
Anemic Spiral NGC 4921 from Hubble
How far away is spiral galaxy NGC 4921? Although presently estimated to be about 310 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe.
Comet Hale Bopp Over Indian Cove
Comet Hale-Bopp, the Great Comet of 1997, was quite a sight. In the above photograph taken on 1997 April 6, Comet Hale-Bopp was imaged from the Indian Cove Campground in the Joshua Tree National Park in California, USA. A flashlight was used to momentarily illuminate foreground rocks in this six minute exposure.
Comet ISON from STEREO
Still intact, on November 21 Comet ISON (C/2012 S1) swept into this animated field of view (left) from the HI-1 camera on the STEREO-A spacecraft. The camera has also captured periodic Comet Encke, Mercury, and Earth, with the Sun cropped out of the frame at the right, the source of the billowing solar wind.
From California to the Pleiades
An astronomical trip from the California Nebula to the Pleiades star cluster would cover just 12 degrees across planet Earth's night sky. That's equivalent to the angular extent of 25 Full Moons, as your telescope sweeps over the borders of the constellations Perseus and Taurus.
The Trail of a Minotaur
Star trails arc above a moonlit beach and jetty in this serene sea and night skyscape. Captured on November 19, the single time exposure looks south down the Atlantic coast from Cape Cod, Massachusetts, USA.