This image covers area of 1.89 x 1.26 deg. around Alnitak (ζ Ori), the easternmost star in the Belt of Orion. There are several nebulae in this region (see annotated mouseover). The Flame Nebula, designated as NGC 2024 or Sh2-277, is an emission nebula about 900 to 1,500 light-years away. Alnitak shines energetic ultraviolet light into the Flame and this knocks away electrons from the clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. Another H II region that extends south of Alnitak is IC 434. It has a very elongated shape in the north-south direction and receives the ionizing wind directly from the star σ Orionis, a brilliant member of the great Orion OB1 association. The temperature of this region was measured by various methods and exploiting various radiation ratios, initially obtaining values between 8000 K and 7600 K, subsequently this value was reduced to 3360 K. An electronic temperature study conducted in 1992, on the other hand, provided a value similar to the previous ones, which is around 6000 K. Additional dark gas and dust lies in front of the bright part of IC 434 and this is what causes the dark network that appears in the center of the glowing gas. This is what we call the Horsehead Nebula (or Barnard 33). All of the above-mentioned nebulae are part of the Orion Molecular Cloud Complex, a huge star-forming region. Four reflection nebulae have been catalogued by Sidney van den Bergh in his catalogue. They are:VDB 50 (or IC 431, DG 72, Bernes 108, Ced 55l, LBN 206.06-16.41, LBN 944, Magakian 130), VdB 51 (or IC 432, DG 74, Bernes 109, Ced 55m, LBN 206.21-16.20, LBN 946, Magakian 133, V901 Ori) ; VdB 52 (or NGC 2023, LBN 954B, Magakian 135, Bernes 111, Ced 55o, IV 24, GC 1226) and VdB 57 (or IC 435, DG 77, Ced 55q, Bernes 112, Magakian 141). As seen, all of them are catalogued in many other catalogs.