324 Bamberga is well-placed all month as it reaches opposition in Perseus
Asteroid 324 Bamberga reaches opposition on 21 November, shining at 9th magnitude in the constellation of Perseus. It is fortuitously well placed at the moment, the asteroid describing a north-bowing arc between mag. +3.8 Nu (ν) Persei and eclipsing binary Algol (Beta (β) Persei).
324 Bamberga begins the month 20 arcminutes southwest of Nu Persei, thereafter heading west and very gently north, before curving southwest towards the quadrilateral of stars formed by Algol, Omega (ω), Pi (π) and Rho (ρ) Persei. It ends the month a degree east and very slightly south of Algol. Over this period its brightness hardly varies, starting and ending the month at mag. +9.2, increasing fractionally to +9.1 in the middle of the month.
Despite being the 324th officially recognised asteroid, Bamberga is quite large. With a mean diameter of 227km, it’s in the top 20 largest asteroids within the main belt. It also has an eccentric orbit that takes it out as far as 3.59 AU from the Sun and in as close as 1.77 AU. This creates a considerable variation in its opposition magnitude, reaching mag. +8.0 when conditions are favourable, allowing it to become the brightest of its class – Bamberga being a C-type, carbon-rich asteroid. Favourable, near-perihelion oppositions occur with a periodicity of 22 years, and the next is due in 2035 when the asteroid will reach mag. +8.1 in September of that year. Bamberga rotates once every 29.43 hours, a long period for such a large asteroid. Its carbon-rich makeup gives it a low reflectivity of just 6%. It was discovered by the prolific Austrian asteroid hunter, Johann Palisa in 1892 and is named after Bamberg, a town in southern Germany.