The sky around vdB 156 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 156 is a reflection nebula in Andromeda, 687 light-years away
vdB 156 is a reflection nebula in the constellation Andromeda, 687 light-years away. spans 3.1° of sky, about 38 light-years across. It is a telescope object, 6 inches or larger, and it is highest in the evening sky in October.
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 156 is vdB 156 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 Omicron And, HD 217675/217676, B6IIIpe+A2p, magnitude 3.6. He rated it faint in brightness and intermediate in color.
Finding vdB 156 from Matar
vdB 156 lies 12.7° north of Matar, the magnitude 2.9 star. A fist held at arm's length covers about 10°.
vdB 156 is highest in the evening in October
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 northern hemisphere and south to about 48°S, and never sets north of 48°N.
vdB 156 is 687 light-years away
The light seen from vdB 156 tonight left it about 687 years ago, around 1339 AD. It ranks 28 of 158 by distance among the Van den Bergh nebulae. Distance source: Hipparcos 2007 parallax via HYG v4.1 (HR 8762, illuminating star).
