September 30 – 81 Terpsichore

Asteroid 81 Terpsichore, discovered on September 30th 1864 by Ernst Wilhelm Tempel, is a large (about 120 km diameter), dark, “C” type (carbonaceous) main-belt asteroid.  Terpsichore is named after my least favourite muse, the one in charge of dancing.  Her name means “delight in dancing“, an alien concept to myself.  According to the epic poem the Dionysica of Nonnus, she was the mother of the Sirens.

Terpsichore by Antonio Canova (Cleveland Museum of Art)

Terpsichore by Antonio Canova (Cleveland Museum of Art)


The Jovian moon Themisto, discovered on September 30th 1975 by Charles Kowal and Elizabeth Roemer, is a rather small, irregular moon, orbiting about halfway between Jupiter’s large, well known Galilean moons and the rather less famous Himalia Group of prograde irregular companions. The best photographs currently available on the Internet show Themisto as a white pinhead on a black background, so I haven’t bothered “borrowing” one.

Themisto was named after a character from Greek mythology, the subject of a tragedy by Euripides which has unfortunately been lost. In the play, Themisto accidentally kills her own children, believing them to be the offspring of her husband’s first wife. When she realises what has happened, Themisto does what the star of any tragedy would be expected to do, and kills herself as well. The Greek stage at an average drama festival was littered with more bodies than an entire season of Murder She Wrote.

Co-discoverer Elizabeth Roemer also has two asteroids to her name, the magnificently named 1930 Lucifer and 1983 Bok. Charles T Kowal does even better, with 19 minor planets discovered between 1970 and 1981, including 2060 Chiron, the first of the centaurs. His collection of astronomical trophies also boasts a few comets, and Leda, another Jovian satellite.


ALSO TODAY . . .

Asteroid 191 Kolga was discovered today in 1878 by C H F Peters, and named in honour of the daughter of a Norse sea God. The name means “chilling wave”.

Chilling Wave

Chilling Wave

Two years later to the day, Johann Palisa added asteroid 219 Thusnelda to his collection. Thusnelda is an S-type main belt asteroid of approximately 38 km diameter. The name comes from a Germanic princess captured in AD 15 by the Roman general Germanicus Julius Caesar , adoptive son of the Emperor Tiberius, and father of Caligula.


September 29 – OSO-7

The Orbiting Solar Observatory 7 (OSO-7 ) was the seventh of eight similar satellites, and was launched on September 29th 1971, straight into a drama, when a problem with the second-stage guidance system left it in an unplanned orbit, and pointing in unexpected directions. Fortunately, John Thole at NASA (who we might well come across again in connection with Echo 2) managed to get the mission back on course with a mix of skill and luck, saving the day. I can’t imagine how he must have felt, slewing this huge craft around from so far away he couldn’t even see it. It’s bad enough when your spaceship is made by Nintendo and you get to start again if you crash.

OSO-& (image credit: NASA)

OSO-& (image credit: NASA)

OSO-7, like its brethren, came in two main parts, known as the “sail” and the “wheel”. The sail faced the Sun (during its day) and measured solar x-rays and coronal activity. The wheel, as the name suggests, rotated continuously, measuring solar x-rays and cosmic x- and gamma-rays. The spinning of the wheel, combined with the axial movements that kept the sail pointing at the Sun, allowed two of the wheel-based experiments to cover the whole sky every six months.

OSO-7 re-entered the Earth’s atmosphere on July 9th 1974.


ALSO TODAY . . . .

1884  —  Discovery of asteroid 243 Ida by Johann Palisa.  Ida has been visited by the Galileo spacecraft.  Thanks to Galileo, we have pretty good photographs of Ida, and we now know it has a small companion, Dactyl.

Ida and Dactyl, courtesy of Galileo (image: NASA/JPL)

Ida and Dactyl, courtesy of Galileo (image: NASA/JPL)

Dactyl is pretty teeny, measuring just over a kilometre across in most directions. The name comes from a race of mythical beings who inhabited Mount Ida in Crete.  They are credited with discovering how to use fire to work metal.


1962  —  Launch of satellite Alouette 1.


1988  —  Launch of shuttle mission STS-26 (“Discovery“).


September 28 – Ananke

Ananke is one of Jupiter’s many smaller moons.  It was discovered on September 28th 1951 by Seth Barnes Nicholson at Mount Wilson Observatory.  It takes its name from the mythological personification of “Necessity” (the word means something similar in Greek).  Ananke was the mother of the Fates (also kmown as the Moirai), their father being Zeus (surprise, surprise).

Ananke

Ananke

Ananke is an irregular retrograde satellite, and lends its name to the Ananke group  of similarly inclined moons, as at 14km in diameter it is the largest of the type (the other members being Praxidike, Iocaste, Harpalyke, ThyoneEuanthe, and Europie).  The retrograde motion and eccentric orbits of the group lend credence to the theory that they may all be the remains of asteroids captured by Jupiter.

As far as I am aware there are no photographs of Ananke that show it as anything more than a faint grey spot.


 ALSO TODAY . . . .

1852  —  Birth of Elizabeth Isis Pogson, the first woman to attempt to gain membership of the Royal Astronomical Society (it took five years for her to succeed).


1876  —  Discovery of asteroids 168 Sibylla (by J C Watson) and 169 Zelia by Paul and Prosper Henry (a rarity, classified as “O-type” in the SMASS-based system devised by Bus and Binzel).


September 27 – 134 Sophrosyne / DAWN

Asteroid 134 Sophrosyne was discovered on September 27th 1873 by Robert Luther. Its a dark, C-type, main belt asteroid, with an estimated diameter, derived from occultation observations, of 110 km (68 miles).

Sophrosyne was one of the many spirits to escape from Pandora’s jar. As a goddess she represents a concept almost completely alien today in the westernised world, that of enlightenment and happiness achieved through harmonious living, restraint, patience and self-knowledge (rather than through the acquisiton of 4x4s and HD-TVs).

There are very few representations of today’s goddess floating around, and to be honest I could have shown you a shot of almost any classically dressed woman looking a bit thoughtful and passed her off as Sophrosyne, but I haven’t.


 ALSO TODAY . . . .

1814  —  Birth of American astronomer, Daniel Kirkwood, the man who noticed the gaps in the asteroid belt which now bear his name.  I look forward to receiving hits from Evertonians (another Dan Kirkwood was a player and director there).


2003  —  Launch of Kaistsat 4 (Korea Advanced Institute of Science and Technology SATellite), aka STSAT-1, with the primary mission of studying galactic hot plasma.


2003  —  Launch of SMART 1 (Small Missions for Advanced Research in Technology) by ESA.  SMART 1 was the first ESA to the Moon, and set a couple of unusual records.  It became the first mission to leave Earth orbit using just solar power, and the slowest ever to the Moon, taking 13 months.  It also holds the record for the lowest fuel consumption on an Earth to Moon journey.  As well as testing new power sources, SMART 1 did carry imaging equipment, and identified this location . . . .

Shackleton Crater viewed by SMART 1 (image credit: ESA)

Shackleton Crater viewed by SMART 1 (image credit: ESA)

. . . . as the best place to site solar panels for a future lunar base.


2007  —  Launch of DAWN, to rendezvous with Vesta and Ceres.  Vesta was visited in July 2011, resulting in this fabulous photograph, below.

Image of Vesta, by DAWN (image credit: NASA)

Image of Vesta, by DAWN (image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Ceres was reached in March 2015, and DAWN is currently (September 2016) orbiting at a height of just over 900 miles, and has been busy sending back excitingly detailed shots like this one . . .

Ceres from DAWN (image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Ceres from DAWN (image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

. . .  and this one:

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/ID

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/ID


September 26 – Asteroid 610 Valeska

Asteroid 610 Valeska was discovered on September 26th, 1906, by Max Wolf at Heidelberg.

The JPL Small Body Database Browser gives a diameter of 19.153 km (I’m happy with “just under 20”).

Now, Lutz D Schmadel’s Dictionary of Minor Planet Names has this one listed in the appendix of bodies for which the origin of the name is unknown.  There was actually a fairly famous Valeska around at the time of the discovery and naming, but I’m not sure whether she was big enough to impress the astronomers of Heidelberg.

Valeska Suratt

Valeska Suratt

Valeska Suratt was born on June 28th, 1882, in Owensville, Indianna, and began an acting career in Vaudeville at the turn of the 20th century.  She moved onto Broadway in 1906, and began a film career in 1915.  Unfortunately Max Wolf, though he did visit the USA, did so way before Suratt became famous.

But a minor detail like that isn’t going to stop me from adding her photograph to today’s blog.

 

September 25 – Asteroid 203 Pompeja

Asteroid 203 Pompeja was discovered on September 25th 1879 by our old workaholic friend Christian Heinrich Friedrich Peters.  There isn’t much to say about it except it’s about 116 km across, and completes one orbit of the Sun every four and a half Earth years.  Peters made all 48 of his asteroid discoveries, between 1861 and 1889, from the Litchfield Observatory at Hamilton College, Clinton, NY.  Unfortunately it has since burnt down.

Pompeii (photo by me)

Pompeii (photo by me)

Pompeja was named after the town of Pompeii, and given a suitably asteroidal name by changing the ending (for some reason they sound better if they finish with an “a”).  Pompeii is an amazing place; you really should go.

Aphelion 3.376 AU
Perihelion 2.082 AU
Orbital period 4.51 years
orbital speed 18.03 km/second
Semi-major axis 2.729 AU
Eccentricity 0.237
Inclination 10.921°
Longitude of ascending node 97.251°

(epoch – Jan 30 2005)


September 24 – Asteroid 318 Magdalena

Asteroid 318 Magdalena, discovered on September 24th 1891 by Auguste Charlois, is a main belt asteroid of about 105 to 106 km diameter, of unknown composition. The reason the name was chosen remains a mystery.

This makes it very difficult to say anything much of interest about this object, leading to a very short blog.  I’ll fill this one out a little with the orbital facts and figures for our mysterious friend Magdalena.

Aphelion 3.461 AU
Perihelion 2.927 AU
Orbital period 5.71 years
orbital speed 16.67 km/sec
Semi-major axis 3.194 AU
Eccentricity 0.084
Inclination 10.641°
Longitude of ascending node 161.671°
Argument of Perihelion 300.312°

(Epoch – Jan 20, 2005).


ALSO TODAY . . . .

1964  –  Launch of Kosmos 46 from the Baikonur Cosmodrome. Kosmos 46 spent 8 days in orbit, taking in the view and photographing it, before returning a capsule of film by parachute.


September 23 – Neptune

Officially, Neptune was discovered visually on September 23rd 1846 by Johann Galle, but its existence had been proposed by Alexis Bouvard years before, and its position was predicted by Urban Le Verrier on August 31st 1846, and by John Couch Adams a couple of days later.  James Challis at the University of Cambridge was also in the running, and observed Neptune twice before the discovery was announced, but failed to realise what was going on.  And Galileo had seen and noted Neptune himself, but even he had no idea what it was.

Neptune from Voyager 1 (image credit: NASA)

Neptune from Voyager 1 (image credit: NASA)

The first suggestion for a name for this new planet came from Galle, who thought Janus might be a good idea, after the two-faced Roman god of beginnings, from whom we get the name of the first month of the year.  Challis, no doubt anxious to make up for being beaten to the finishing tape, suggested Oceanus (whose children we have been meeting all year in the guise of asteroids).

Le Verrier was the first to suggest naming the new planet Neptune, the Roman god of the sea, and appropriately a brother of Jupiter and Pluto (he also suggested, modestly, Le Verrier, but this idea didn’t gain much support outside France).  The name is used almost universally, although as Neptune was the Roman equivalent to the Greek Poseidon, Greece is, as far as I’m aware, the only western country to use that name instead.

Neptune is a small giant (yes, I know what I just said).  It is 17 times more massive than Earth, but only about 5% as massive as Jupiter.  It is similar in composition to Uranus, and the two of them, while still coming under the “gas giant” umbrella, are sometimes also referred to as “ice giants”.

As with the other giants, Neptune has a ring system, but not one that’s going to be used as a backdrop to an episode of Star Trek anytime soon.  The rings are fairly thin, and few enough in number to have been named after some of the players in Neptune’s discovery (the Adams, Le Verrier, Lassell, Galle and Arago rings).

Neptune's Rings (image credit: NASA)

Neptune’s Rings (image credit: NASA)

At last count Neptune was known to have fourteen moons, all named after water deities.  I’ll just briefly mention that the biggest are Triton (way bigger than the rest at 2,700+ km diameter), Proteus, Nereid, Larissa, Galatea and Despina, but as all fourteen will probably be turning up in these pages over the next twelve months, we will leave it at that for now.

Just as an aside, it has been speculated that in the dim and distant past of the solar system there might have been a fifth gas giant, which was flung out of orbit by a strong gravitational kick from Jupiter or Saturn.


ALSO TODAY . . . .

1791  –  Birth, in Hamburg, of Johann Franz Encke, comet hunter, and expert at predicting when they were going to return. Encke also has a gap in Saturn’s rings named after him, in recognition of his observations of that planet.


September 22 – Asteroid 57 Mnemosyne

Discovered on this very day in 1859 by Robert Luther, 57 Mnemosyne is a main belt asteroid of about 113km across, sweeping round the Sun at 16.7km/s,  and taking about five and a half years to complete one orbit. Mnemosyne is a stony “S” type asteroid, with an albedo of 0.215. S types are generally brighter than most, with Iris able to reach +7.0 at opposition.

Mnemosyne was a titaness (a daughter of Uranus and Gaia),  and was mother of the nine Muses (Zeus was the father, and somehow managed to persuade Mnemosyne that they needed to sleep together for nine nights to get the job done).

It is from Mnemosyne that we get the word mnemonic.


1862  –  Asteroid 75 Eurydike discovered by C H F Peters.

Orpheus and Euridice, by Christian Gottlieb Kratzenstein.

Orpheus and Euridice, by Christian Gottlieb Kratzenstein.


1878  –  Asteroid 190 Ismene, a member of the Hildian family, discovered by C H F Peters. The family are named after asteroid 153 Hilda.


1884  –  Asteroid 242 Kriemhild discovered.


2004  –  Planetoid 120347 Salacia discovered.  Salacia has an incredibly high number, but is significant because, as you will have noticed, I used the word “planetoid”, indicating it isn’t one of my normal day-to-day asteroids.  This particular Kuiper belt object is estimated to be 850 km (530 miles) in diameter.


September 21 – 149 Medusa

Henri Joseph Anastase Perrotin discovered today’s asteroid, 149 Medusa, on September 21st 1875, at which time I believe he was working at Toulouse Observatory. His name is quite impressive,  so his discoveries are normally just credited to J Perrotin.

Medusa, despite being a bright stony asteroid, was a good catch for Perrotin, as it was the smallest to have been found at the time.

Medusa

Medusa

Medusa, of course, was the hideous female gorgon with snakes for hair who turned to stone anyone who met her gaze. She was one of three sisters (the others being Stheno and Euryale) who were the children of the marine deitiesPhorkys and Keto. Medusa was killed by Perseus, who then presented her head to Athene to attach to her shield. The word gorgon, incidentally, comes from the same root as the Sanskrit word “garg”, meaning a monster (from the noise they generally make).


Twelve years later, on September 21st 1887, Johann Palisa discovered 269 Justitia, a much larger main belt asteroid which was named after the Roman goddess whose Greek equivalent was Themis.

Themis, the personification of divine law and order, was one of the original twelve Titans, descendants of Gaia and Uranus, who ran the world until the Olympian gods showed up and overthrew them.