The sky around vdB 99 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 99 is a reflection nebula in Scorpius, 586 light-years away
vdB 99 (Ced 125d, LBN 1093, LBN 1094) is a reflection nebula in the constellation Scorpius, 586 light-years away. spans 3.3° of sky, about 34 light-years across. It is a telescope object, 6 inches or larger, and it is highest in the evening sky in July.
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 99 is vdB 99 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 Fang (Pi Sco), HD 143018, B1V+B2V, magnitude 2.9. He rated it moderate in brightness and very blue in color.
Finding vdB 99 from Dschubba
vdB 99 lies 3.5° south of Dschubba, the magnitude 2.3 star. Three fingers held at arm's length cover about 5°.
vdB 99 is highest in the evening in July
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 64°N, and never sets south of 64°S.
vdB 99 is 586 light-years away
The light seen from vdB 99 tonight left it about 586 years ago, around 1440 AD. It ranks 25 of 158 by distance among the Van den Bergh nebulae. Distance source: Hipparcos 2007 parallax via HYG v4.1 (HR 5944, illuminating star).
