VDB9

Fri, 11 Jan 2019 08:50:55 +0100

VDB 9, LDN1352/1353 in Cassiopeia ASA N10“ @1050mm Paracorr Trius 694 L 1100min ASK8“ @540mm SXV-H9 RGB a‘340min 8min subs total   35h Gahberg 20181013 bis 1228 Explanation: Centered in a well-composed celestial still life, pretty, blue vdB 9 is the 9th object in Sidney van den Bergh's 1966 catalog of reflection nebulae. It shares this telescopic field of view, about twice the size of a full moon on the sky, with stars and dark, obscuring dust clouds in the northerly constellation Cassiopeia. Cosmic dust is preferentially reflecting blue starlight from embedded, hot star SU Cassiopeiae, giving vdB 9 the characteristic bluish tint associated with a classical reflection nebula. SU Cas is a Cepheid variable star, though even at its brightest it is just too faint to be seen with the unaided eye. Still Cepheids play an important role in determining distances in our galaxy and beyond. At the star's well-known distance of 1,540 light-years, this cosmic canvas would be about 24 light-years across.