Today in 1877, Canadian-American astronomer James Craig Watson discovered his final asteroid, the large main belt member179 Klytaemnestra. This stony S-type asteroid is about 75 km across, and has a light curve giving it a rotation period of 11.13 hours, varying in by magnitude by 0.55.
A light curve is pretty much exactly what you might think. It’s a curve showing variations in brightness of the target object. Variations in the light intensity recorded can be used to infer how long it is taking the asteroid to rotate. The same method can be used to predict the shape of the asteroid.
As was fairly normal in the early days of asteroid naming, this one is a mythological Greek reference. The Spartan princess Clytemnestra was the wife of Agamemnon, king of Mycenae, and became infamous by killing both her husband and the Trojan princess Cassandra, whom he had chosen as a reward for his part in the victory over Troy.
1875⇒ I love this name. Vesto Melvin Slipher, the American astronomer responsible for providing the first proof of universal expansion, was born today in Mulberry, Indianna. Slipper lived to the grand old age of 93, and spent his entire working life at the Lowell Observatory in Flagstaff, Arizona. His brother, Earl, was also an astronomer, specialising in the study of Mars.
I have no idea where his parents got the name Vesto from, but if you conjugate the Italian verb vestirsi (to wear or get dressed) you come across it pretty quickly (1st person present indicative – I dress).
1982 ⇒ Launch of the fifth NASA shuttle mission, STS-5, using shuttle Columbia. The four-man crew was the first to undertake an “operational” shuttle mission, by deploying two commercial satellites.
The bright 27 Euterpe is a large main belt asteroid, discovered by John Russell Hind on November 8th 1853. At opposition Euterpe can get to magnitude 8.3, making it one of the brightest asteroids.
Euterpe was Hind’s penultimate asteroid. He had discovered four the year before, so probably thought he was headed for the record books. But they dried up pretty quickly, with just this one in 1853, and one last find in 1854 (30 Urania). Hind has a crater on the Moonnamed in his honour, lying next to the crater Halley, the namesake of which is celebrating (quietly, I assume) his 361st birthday today.
Euterpe was named after the muse of music, the name deriving from the Greek meaning something approximating to “delight” or “rejoicing”.
Today’s space-filler is by the Belgian artist Godefroid Guffens, a pupil of Nicaise de Keyser, born in Hasselt, but working mostly in Antwerp.
1656 – Birth of Edmund Halley.
1875 – Discovery of asteroid 155 Scylla.
1956 – Comet Arend-Roland discovered.
1958 – Launch of Pioneer 2 in the direction of the Moon. An altitude of almost 1,000 miles was achieved, but unfortunately the Moon is another 237,000 miles further up. Actually, that flippant remark is only partly true. The average distance to the Moon is about 238,000 miles, but the actual distance varies from 225,000 miles at perigee (closest approach to Earth) to 252,000 miles at apogee (furthest distance from Earth).
47 Aglaja (the “aja” is pronounced like the “iar” in “friar”) is a C-type main belt asteroid, about 140 km (80 miles) wide, following a fairly average path around the Sun at a fairly average speed of about 17.5 km/s. It was discovered on September 15th 1857 by one of our regular contributors, Robert Luther, and was named after one of the Charites of Greek mythology (who have become more famous under their Roman name of the Graces). Aglaia (or Aglaea) was responsible for splendour. We have already encountered another of the trio, Euphrosyne, (“mirth”) on September 1st, but we won’t be coming across the third, Thalia (“good cheer”), because she shares her name with the more popular Muse of Comedy, who we will probably meet on December 15th.
Today’s accompanying artwork is by the German artist and former student of Albrecht Dürer, Hans Baldung (c. 1484 to 1545). In this painting I have no idea which Grace is which. There is probably a clue in the book being read by the grace on the left, and the lute-like instrument carried by the one on the right, but their identification eludes me.