M78
NGC 2068
物性
位置と識別子
可視性
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M78について
説明
M78 is the brightest diffuse reflection nebula in the sky, located about 1,600 light-years away in Orion. It is part of the Orion Molecular Cloud Complex and spans about 4 light-years. Two 10th-magnitude stars (HD 38563A and B) illuminate the surrounding dust, which reflects their light to give the nebula its blue-white color.
観測のコツ
Located about 2 degrees northeast of Alnitak (Zeta Orionis), the leftmost belt star. In binoculars it appears as a small, faint hazy patch. A 4-inch telescope at 60-80x shows a comet-like fan of nebulosity around two embedded stars. An 8-inch telescope reveals more extent and mottled structure. Unlike emission nebulae, nebula filters do not help (M78 is a reflection nebula). Dark, transparent skies are important. Best observed from November through March.
歴史
Discovered by Pierre Mechain in early 1780. Charles Messier cataloged it on December 17, 1780. It is one of only a few reflection nebulae in the Messier catalog (the blue component of M20 being another).
豆知識
M78 sits at the edge of a vast molecular cloud containing enough material to form thousands of stars. In 2004, the nearby reflection nebula McNeil's Nebula appeared suddenly when a young variable star (V1647 Orionis) brightened dramatically, illuminating a previously dark patch of dust — a rare example of a nebula appearing in real time.
コミュニティ写真 (1)
Credit: ESO/Igor Chekalin. License: CC BY 4.0. (Wikimedia Commons)
Skybred Feb 28, 2026