Astronomy Picture of the Day

Explanation: Here lie 526,230,881 of the brightest stars known. The US Naval Observatory has deployed their monster Precision Measuring Machine to digitize photographic plates covering the whole sky and creating the above map. Yellow corresponds to 150,000 stars per square degree, while dark blue corresponds to only 500 stars per square degree. (For comparison, the Full Moon takes up about 1/4 of a square degree.) The most striking feature on this whole sky projection is the central disk of our Milky Way Galaxy, which stretches across the middle. Dark dust lanes are evident there by the great number of stars they obscure. The two bright spots seen south of the Milky Way's disk are the neighboring Magellanic Cloud galaxies. Anyone can order a free copy of this data, but not everyone can fit data from all 526,230,881 stars on their hard-drive.

January February March April May June July August September October November December

<  April 1999   > Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Publications with keywords: POSS - sky
Publications with words: POSS - sky
See also:

• Martian Analemma
• Venus Falls Out of the Evening Sky
• Aurora Through a Moonlit Sky
• Loop I in the Northern Sky
• The Radio Sky: Tuned to 408MHz
• A Chamaeleon Sky
• Dark Sky, Bright Sun

All publications on this topic >>