DETAILS
Exposure: 20×600″ + 20×600″ @ ISO 800
Telescope: William Optics Megrez 88FD with flattener/reducer Borg DG-L
Filter: Hutech IDAS LPS P2 2″
Mount: Skywatcher EQ6 Pro
Camera: Amp-off Modded & Cooled Canon 350D
Date: 4th December 2010
Location: Coll d’Ares (Lleida, Spain)
Comments: It was a very cold night (-7ºC) with very good transparency and low humidity… ideal conditions for astrophotography. This is a very beatiful area of the sky plenty of beautiful and curious nebular objects. This image was selected as NASA’s Astronomy Picture of the Day on January 21st, 2011!

Mintaka, Alnilam and Alnitak are the three big stars in this picture. They are bluish stars thousands of times brighter and much hotter than our sun. This gorgeus asterism of stars is known as the Orion’s Belt.
Mintaka, also known as Delta Orionis, is the faintest of the three stars in Orion’s Belt. It is a multiple star system, composed of a large B-type blue giant and a more massive O-type white star. The Mintaka system constitutes an eclipsing binary variable star, where the eclipse of one star over the other creates a dip in brightness. Mintaka is the westernmost of the three stars that constitute Orion’s Belt. In the image it’s the star bright star at the upper side.
Alnilam, also known as Epsilon Orionis, is a B-type blue supergiant, despite being nearly twice as far from the Sun as Mintaka and Alnitak, the other two belt stars, its luminosity makes it nearly equal in magnitude. Alnilam is losing mass quickly, a consequence of its size; approximately four million years old. It’s the bright star near the center of the image.
Alnitak, also known as Zeta Orionis, is the easternmost star in Orion’s Belt. It is a triple star some 800 light years distant, with the primary star being a hot blue supergiant and the brightest class O star in the night sky. It is the bright star at the bottom of the image, just above the flame nebula.