The sky around vdB 84 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 84 is a reflection nebula in Canis Major, 2,840 light-years away
vdB 84 is a reflection nebula in the constellation Canis Major, 2,840 light-years away. spans 5.6′ of sky, about 4.6 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 84 is vdB 84 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 CP-27 1408, B5, magnitude 9.2. He rated it moderate in brightness and very blue in color.
Finding vdB 84 from Sirius
vdB 84 lies 10.7° south of Sirius, the magnitude -1.4 star. A fist held at arm's length covers about 10°.
vdB 84 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 63°N, and never sets south of 63°S.
vdB 84 is 2,840 light-years away
The light seen from vdB 84 tonight left it about 2,840 years ago. It ranks 108 of 158 by distance among the Van den Bergh nebulae. Distance source: Gaia DR3 parallax of the illuminating star via AT-HYG v3.2 (872 pc).
