The sky around vdB 51 at true scale, north up and east left, with stars to magnitude 8. The circles show the field of a low-power eyepiece and of 10×50 binoculars.
vdB 51 is a reflection nebula in Orion, 1,280 light-years away
vdB 51 (IC 432, LBN 946, Ced 55m) is a reflection nebula in the constellation Orion, 1,280 light-years away. spans 10′ of sky, about 3.7 light-years across. It is a telescope object, 6 inches or larger, and it is highest in the evening sky in February.
Nebula: a cloud of gas and dust. Emission nebulae glow on their own, lit by ultraviolet light from hot young stars; reflection nebulae shine by starlight scattered from dust; dark nebulae block the light behind them.
vdB 51 is vdB 51 in the Van den Bergh catalog of reflection nebulae
Sidney van den Bergh listed it in his catalog of reflection nebulae (1966), drawn from the Palomar Sky Survey. He chose nebulae lit by a star bright enough to appear in the Bonner and Cordoba star catalogs. The star that lights it is HD 37776, B2V, magnitude 7.0. He rated it very bright in brightness and blue in color.
Finding vdB 51 from Alnitak
vdB 51 lies 26′ north of Alnitak, the magnitude 1.7 star. That is within one binocular field.
vdB 51 is highest in the evening in February
The chart gives its height above the horizon at 9 pm through the year, from 60°N to 40°S. It can be seen from the whole southern hemisphere and north to about 88°N.
vdB 51 is 1,280 light-years away
The light seen from vdB 51 tonight left it about 1,280 years ago, around 746 AD. It ranks 63 of 158 by distance among the Van den Bergh nebulae. Distance source: Gaia DR3 parallax of the illuminating star via AT-HYG v3.2 (393 pc).
