August 15 – Discovery of Asteroid 101 Helena (1868)

Asteroid 101 Helena was discovered by James Craig Watson on August 15th 1868. Helena is a main belt asteroid, and for most purposes we can say it is about 66km across, though if you need to be more precise, Observations from Arecibo Observatory have fine-tuned this to 71 x 63 x 63 km. Helena is classified as an “S-type” asteroid in the Tholen¬†system introduced by David James Tholen in 1984.

The Rape of Helen.
The Rape of Helen.

If you know anything at all about Greek mythology you have probably already guessed that Helena is named after Helen of Troy (or Helen of Sparta), daughter of Zeus and Leda, abducted in youth by Perseus, married to King Menelaus of Laconia, then abducted again, this time by Prince Paris of Sparta, after which, according to Homer, it all kicked off.

Eight years later, on August 15th 1876, asteroid 166 Rhodope was discovered by C H F Peters in Clinton, New York. Rhodope is a GC type asteroid, and is a member of the approximately one thousand strong Adeonian family, formed sometime within the past 600 million years from their parent, 145 Adeonia.


Queen Rhodope of Thrace was wife of King Haemus, who made the mistake of offending Zeus and Hera. The punishment was unusual: he and Rhodope were turned into mountain ranges. Haemus is now the Balkans, and his queen became the Rhodopes, which straddle the Greek/Bulgarian border.