Alnitak [ http://www.astro.ui…], Alnilam [ http://www.astro.ui…], and Mintaka [ http://www.astro.ui…], are the bright bluish stars from east to west (left to right) along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion [ http://www.gb.nrao.…belt.html ], these three blue supergiant stars are hotter and much more massive than the Sun. They lie about 1,500 light-years away, born of Orion's [ http://www.gb.nrao.…optical.html ] well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have intriguing and some surprisingly familiar shapes, including the dark Horsehead [ http://antwrp.gsfc.…] Nebula and Flame Nebula [ http://antwrp.gsfc.…] near Alnitak at the lower left. The famous Orion Nebula [ http://antwrp.gsfc.…] itself lies off the bottom of this star field that covers an impressive 4.4x3.5 degrees on the sky. The color picture was composited from digitized [ http://www-gsss.sts…] black and white photographic plates recorded through red and blue astronomical filters, with a computer synthesized green channel. The plates were taken using the Samuel Oschin Telescope [ http://www.astro.ca…], a wide-field survey instrument at Palomar Observatory [ http://www.astro.ca…], between 1987 and 1991.
