December 22 – Discovery of Asteroid 323 Brucia (1891)

Thirty-three kilometre wide asteroid 323 Brucia was the first to be discovered by the new fangled process known as astrophotography.

It was discovered by Max Wolf, and named in honour of Mrs Catherine Wolfe Bruce, who had donated the instrument on which it was captured, the 16 inch double astrograph at Heidelberg.

The Bruce Astrograph, Heidelberg

Mrs Bruce was a generous supporter of astronomy (she also provided instruments for Harvard and Yerkes), and now, as well as an asteroid, has a lunar crater named after her. She established an annual award for the Astronomical Society of the Pacific, the “Catherine Wolfe Bruce Gold Medal”, one of the most prestigious awards in astronomy. Over the years the Bruce Medal has been awarded to the likes of Poincaré, Hubble, Hoyle and Chandrasekhar, and also to a certain Max Wolf, who received the honour in 1930.

I’ve included a picture of the Bruce Medal because photographs of Catherine are hard to come by.  There’s one doing the rounds online, but I’m fairly sure it isn’t her, so I’m not using it.

December 22 – Discovery of Asteroid 264 Libussa (1886)

Discovered on December 22nd 1886 by C H F Peters, asteroid 264 Libussa is an asymmetrical S-type main belt asteroid of somewhere between 50 and 60 km diameter.

It was named after Libussa (Lubossa or Libuše), a half-elf daughter of the mythical Czech king Krok. She eventually became the founder of the city of Prague, and ancestor of the whole Czech nation.

Libuse (photo credit: Palic Kap)
Libuse (photo credit: Palic Kap)

Today’s photo shows a detail from the Octárna Hotel, Kroměříž, Czech Republic. This is alunette (a half moon shaped space) by local artist Max Švabinský. It shows Princess Libuse prophesying the glory of Prague.

There’s not a great deal more to say about Libussa, so it’s back to orbital characteristics. To date we have come across aphelion (3.18 AU for this particular rock), perihelion (2.42 AU), semi-major axis (2.8 AU), longitude of ascending node (49.8°), and inclination (10.4°). Today we add another important element of an asteroid’s orbit: the argument of perihelion. For Libussa, this is 339.27°, and in orbital calculations it is depicted by the letter ω. It’s not a “w”, by the way, but a lower-case omega (the word means “great o”) the last letter of the Greek alphabet. Remember that, because one of these days I’m going to work out how to put some of these calculations in this blog in the form of a table.

The argument of perihelion is the angle between the perihelion and the ascending node. So if, for example, the value was 90°, that just means that the asteroid would be at perihelion when it reached the northerly point in its orbit.

1891 ⇒ Asteroid 323 Brucia becomes the first asteroid to be discovered by astrophotography, by Max Wolfe.