October 05 – Asteroid 36 Atalante

There’s not a great deal to say about 36 Atalante, except that it is in the main belt, has a fairly large, dark, slightly elongated body, and was discovered on October 5th, 1855 by Hermann Goldschmidt.

Atalante and Hippomenes (Nicolas Colombel)

Atalante and Hippomenes (Nicolas Colombel)

The asteroid is named after the mythological Greek huntress Atalanta, who married Hippomenes after he won her hand by the unusual means of beating her in a foot race. She was a good runner though, and Hippomenes would have been killed had he lost, so he needed to slow her down, and used the lure of golden apples provided by Aphrodite strewn in her path to achieve this.

Italian astronomer Giorgio Abetti was born in Padua on this day in 1882. His father was also an astrononer, specialising in positional astronomy, but Abetti junior was a solar specialist, and led expeditions to observe eclipses from Siberia in 1936 and the Sudan in 1952. He now has his own lunar crater on the edge of the Mare Serenitatis which he shares with his father, and an asteroid, number 2646.

Asteroid 37 Fides was discovered today in 1855 by Robert Luther.

Asteroid 2839 Annette discovered in 1929 by Clyde Tombaugh and named after his daughter.


April 29 – 68 Leto

Asteroid 68 Leto was discovered by Robert Luther on April 29th 1861.  It’s a fairly big main belt asteroid (about 125km diameter) with an absolute magnitude of 6.78, and an apparent magnitude from down here of 9.56 when at its brightest.

Leto was the daughter of the Titans Coeus and Phoebe, and mother (by Zeus, of course) of Apollo and Artemis.  She was thought to have been born on the island of Kos.  Apart from her role in bearing two important gods, Leto is hardly heard about in Greek writing and seems to have been content to remain in the Olympian background.  This fits in with her being generally portrayed as a demure woman, modestly lifting her veil.  The word letho means “to move unseen”, which may explain it.  Perhaps she’s hiding from Hera, Zeus’ wife.

Latona and the Lycian Peasants, by Jan Brueghel the Elder (about 1605).

Latona and the Lycian Peasants, by Jan Brueghel the Elder (about 1605).

The oil painting above, by Jan Brueghel the Elder, shows another incident from Leto’s life, also concerning Hera.  In a foul mood at discovering that Leto was to bear children to Zeus, Hera cursed her to be shunned everywhere she went.  In the painting, she is attempting to drink from a pond in Lycia (southern Turkey), but is being prevented from so doing by the locals, who are stirring up the mud from the bottom of the pond.  She responded by turning them into frogs.

Also today, it now transpires that in 1801 main belt asteroid 69 Hesperia was discovered by Italian astronomer Giovanni Schiaparelli from Milan.  Previously the discovery date had been thought to be April 26, but in an editorial notice of August 29th 2015 the Minor Planet Center announced that an examination of the literature of the time of the discovery shows that the date should in fact be pushed back three days.

Being a patriotic kinda guy, Schiaparelli had named his new discovery in honour of his home country, but for some reason used the Greek name for Italy rather than the Latin (or Italian) one.  The M-type Hesperia is a fairly chunky size, and would be about 130 km in diameter, if it were a sphere (which it isn’t).  I use the word “diameter” a lot in this blog to describe asteroids, but it just means “wide in no particular direction”.

April 17 – 17 Thetis

Today’s lump of rock, asteroid 17 Thetis, was discovered in 1852 by yesterday’s birthday boy, Robert Luther.  It was the first asteroid he discovered.

Thetis is a main belt asteroid approximately 90 km across, with an absolute magnitude of 7.76 (apparent magnitude from 9.9 to 13.5).

Not a great deal is known about Thetis, but it is thought to be an “S-type” asteroid (the S stands for stony).   S-types are the second most common asteroids after “C-types” (C = carbonaceous).

Black figure hydria showing Thetis and the Nereids mourning Achilles

Black figure hydria showing Thetis and the Nereids mourning Achilles

Most references to Thetis (goddess of water)  in Greek literature relate in some way to her role as mother of Achilles, the greatest warrior of the Trojan Wars, but she did have some adventures of her own, most notably protecting Zeus from a plot to overthrow him by summoning Briarius, a friendly “Hekatonkheire”, Greek for “hundred-handed one” (and just in case that wasn’t frightening enough, they had fifty heads as well).

2014  –  NASA announced the discovery of Kepler-186F by the Kepler mission, which is using the “transit” method to discover exoplanets.   Kepler had already discovered hundreds of planets, but this was the first Earth-sized planet, orbiting a red dwarf, to be spotted.  The Kepler team believes that red dwarf stars could provide the majority of “habitable zone” planets, and Kepler-186F is on the edge of the host star’s habitable zone, in an orbit similar to that of Mercury.

Kepler-186F, is, unsurprisingly, orbiting a star known as Kepler-186.  This is an “M dwarf” (the Sun is a “G dwarf”) about 500 light years away.  M dwarfs are the most populous type of star in the known universe (7 out of 10 stars fall into this category, even though they can’t be seen by the naked eye). M dwarf stars are much dimmer than the Sun, and smaller, some being only 8% the mass of our star.

Comparison graphic for Kepler-186F (image: NASA)

Comparison graphic for Kepler-186F (image: NASA)

We should probably resist the temptation to get too excited about the possibility of life on Kepler-186F.  It is not known whether it has an atmosphere, and NASA are uncertain as to whether the planet is “tidally locked”, which would be unhelpful to life, or subject to flares from the parent star, which would be fatal.   However, NASA say that the differences between the conditions on Earth and K-186F don’t rule out the possibility of life.

1861  –  Asteroid 67 Asia discovered by Norman Robert Pogson.

1888  –  Asteroid 276 Adelheid discovered by Johann Palisa.  The origin of the name is not known.  There were probably a few Adelheids (and Adelaides) around at the time, but the most high-profile was Princess Adelheid of Hohenlohe-Langenburg, a niece of Queen Victoria.  Unfortunately I can’t find anything spectacular happening in her life in 1888.  Another posibility though, is Princess Helena Adelaide of Schleswig-Holstein-Sonderburg-Glücksburg, born in 1888 (the name Helena had already been taken for an asteroid discovered by  J C Watson in 1868).  Who can say?

1970  –  Splashdown of Apollo 13, following the scariest mission of the entire manned Apollo program.

View of the Moon from Apollo 13 (image credit: NASA).

View of the Moon from Apollo 13 (image credit: NASA).

April 16 – Robert Luther: Asteroid Hunter

Today is the birthday of Karl Theodor Robert Luther, born in 1822 in the town of Schweidnitz, which is now in Poland, but at the time was in Germany (where it remained until the end of WWII).

Luther discovered 24 asteroids between April 1852 and February 1890.  He died on February 15, 1900.  Like several other asteroid hunters, he is now honoured with a lunar crater and his own asteroid, 1303 Luthera (discovered March 16, 1928 by A. Schwassmann).

One of his asteroids, 90 Antiope, is very interesting (as asteroids go) because it consists of two almost identically sized bodies.  There’ll be more about that on October 1st.

1756  –  Death of Jacques Cassini.

1972  –  Launch of Apollo 16.

April 02 – 108 Hecuba

Asteroid 108 Hecuba was discovered on April 2nd 1869 by Karl Theodore Robert Luther, and is in the wrong place, living as it does with the Hygiea family of main-belt asteroids, but not being related to them (they are C-types, whereas Hecuba is a stony S-type.


Hecuba is the Latin form of the Greek name Hecabe, the wife of King Priam of Troy, and mother of Hector.  I’ve said it before and I’ll say it again:  read the Iliad! 

1964  –  Launch of the Zond 1 spacecraft by the USSR.  A total of ten missions carried the incredibly futuristic and alien-sounding Zond name.  If you’re Russian though, it’s a bit more mundane: it means “probe”.  This was the second Soviet craft to reach Venus.  Unfortunately contact had been lost before the big day.

1998  –  The Transition Region and Coronal Explorer (TRACE) was launched from Vandenberg Air Force Base to observe our nearest star.

TRACE Image of a Sunspot (image credit: Stanford-Lockheed Institute for Space Research / NASA)

TRACE Image of a Sunspot (image credit: Stanford-Lockheed Institute for Space Research / NASA)

TRACE returned a fabulous gallery of images, dozens of which can be viewed here.

March 24 – Concordia

On March 24 1860 Karl Theodor Robert Luther discovered the C-type asteroid 58 Concordia from the Düsseldorf-Bilk Observatory.  As you may remember (I mention it every so often) Luther discovered 24 asteroids in all.  This one was named after the Roman goddess of marital harmony and understanding.  The name was chosen by Karl Christian Bruhns, the recently appointed professor of astronomy at the University of Leipzig.

Concordia (image credit: Andreas Praefcke)

Concordia (image credit: Andreas Praefcke)

Concordia is a main belt asteroid, 90-odd km wide, orbiting at between 2.5 and 2.8 AU, and taking 4.44 years to orbit the Sun.  It is a member of the Nemsis family, a medium-sized asteroid family with about 250 known members, predominantly C-types.

1781   –   Messier 105 (NGC 3379).  If you think back a couple of days you might remember me mentioning a group of galaxies in Leo containing M95 and M96, both of which were discovered on March 20th 1781.  M105 is also in the group, and it was discovered on March 24th 1781, also by Messier’s assistant Pierre Méchain, who was on a roll.  Unlike the other two, this one is an elliptical galaxy, and is known to have a supermassive black hole at its centre.

M105 (image credit: NASA)

M105 (image credit: NASA)

M105 is the brightest elliptical galaxy in this particular group.  It is an E1 type, and is approximately 38 million light years away from Earth.  The “E” rating for galaxies is based on their elongation, where “E0” is fairly round, while “E7” is extremely stretchy.  E1 galaxies are only slightly elongated.

March 15 – Alan Bean

Captain Alan LaVern Bean, USN, was born on this day in 1932 in Wheeler, Texas (100 miles east of Amarillo).

Alan Bean on his way down. (Image credit: NASA)

Alan Bean about to do the almost impossible. (Image credit: NASA)

Bean clocked up 69 days in space aboard Apollo 12 (he was the 4th person to undertake the highly improbable act of walking on the Moon) and Skylab mission SL-3. Following his retirement from NASA, Bean turned his attention to painting. As far as I know, he is the only artist to incorporate genuine Moon dust into his work.

1853  –  Asteroid 78 Diana was discovered on March 15th, 1853 by Robert Luther, the German astronomer who discovered 24 asteroids. According to IRAS observations Diana is about 120 km across, a figure that matches quite well with the 116 km diameter obtained from observations of the occultation of star SAO 75392 in 1980. Diana is named after the Roman goddess of the hunt, and her Greek equivalent, Artemis, will be turning up in these pages later in the year (discovered September 16th, 1868).

1873  –  Asteroid 118 Peitho discovered by Robert Luther. This main belt asteroid is about 47 km in diameter, and categorised as S-type. There are a couple of Peitho‘s in Greek mythology, with the most likely candidate for this naming ceremony being the goddess of seduction, an attendant of Aphrodite. Her Roman name, Suada, presumably shares a root with the Latin persuadere , the place from where we get the middle English word persuasion.

1895Asteroid 400 Ducrosa discovered by Auguste Charlois. It was named after Joseph Ducros, a technician at the Nice Observatory.

March 01 – Asteroids-R-Us

1854  –  28 Bellona and 29 Amphitrite

Asteroid 28 Bellona was discovered by Robert Luther on March 1st 1854, three weeks before the start of the Crimean War, so the name was chosen to be topical (Bellona was a Roman goddess of war).   Bellona is a large S-type asteroid of somewhere between 110 and 120km across.

An even larger S-type asteroid, at over 200km wide, is 29 Amphitrite, discovered on the same day, several hundred miles from Luther in Regent’s Park, London, by another German astronomer, Albert Marth.  Marth was working at the time for George Bishop, the owner of a private observatory in the park.  Bishop chose the name.  Amphitrite was Marth’s only asteroid, but John Russell Hind, who we meet in these pages every so often, used Bishop’s 7″ refractor to greater effect to discover ten asteroids between 1847 and 1854.  Unfortunately the observatory is no longer in Regent’s Park; the telescope was moved to his son’s residence in Twickenham after Bishop’s death, and then donated to an Italian Observatory.

In ancient Greek mythology, Amphitrite was a Nereid, and wife of Poseidon.

1878  –  185 Eunike

185 Eunike is a dark, large, carbonaceous main-belt asteroid, approximately 157 kilometres in diameter. It was discovered on March 1st, 1878 by Christian Heinrich Friedrich Peters, and named, in a politically motivated fashion after yet another Nereid, Eunike, whose name means ‘happy victory’.  This is a reference to the Treaty of San Stefano, signed on March 3rd 1878 between the Russian Empire and the Ottoman Empire at the end of the Russo-Turkish War. The treaty led to the creation of an autonomous Bulgaria, became the central point of Bulgarian foreign policy, lasting until 1944, and led to the Second Balkan War and Bulgaria’s entry into World War I.

1891  –  306 Unitas

306 Unitas is another main belt asteroid, discovered by Elia Millosevich on March 1st, 1891. in Rome, and named by the director of the Modena Observatory in honor of the Italian astronomer Angelo Secchi.  It is classified as an S-type asteroid.  Unitas has a similar orbit to the Vesta family, but has been found to be unrelated to them.

1894  –  385 Ilmatar and 386 Siegena

385 Ilmatar is a large main belt asteroid discovered by Max Wolf on this day in 1894.  Ilmatar is the virgin spirit of the air in Finnish mythology.

Ilmatar (R W Ekman)

Ilmatar (R W Ekman)

386 Siegena is another large, C-type asteroid.  It, too, was discovered by Max Wolf in 1894.  It is named after the city of Siegen in Germany.


September 15 – 47 Aglaja

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 popularMuse of Comedy, who we will probably meet on December 15th.

The Three Graces

The Three Graces

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.

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August 25 – Cupid and Mab

Today in 2003  –  Cupid and Mab, moons of Uranus, both of which had been too dim to see on Voyager photographs, discovered by Mark R Showalter and Jack J Lissauer using the Huble Space Telescope. Cupid was named after the character in Timon of Athens, and Mab after the queen of the fairies who is mentioned in Romeo and Juliet (and as a long-time fan I would also refer you to The Fairy Feller’s Master Stroke on the album Queen II).  Mab has unusual hobbies. She drives her chariot (which I believe is made from an acorn) up people’s noses to enable her to influence their dreams, and she is thought to decide who gets infected by herpes simplex.

The best picture I could find of Mab.

The best picture I could find of Mab.

Neither Cupid nor Mab could be described as impressive bodies.  Cupid measures about 18 km in diameter, while Mab is thought to be about 24 km.

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Asteroid 84 Klio discovered by R Luther in 1865.  Clio (or Klio or Kleio) was the muse of history.  A daughter of Zeus and Mnemosyne, she had one son, to whom she gave the butchly masculine name Hyacinth. Her own name is derived from the verb kleô, meaning to celebrate or make famous.

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1889 – Asteroid 287 Nephthys discovered by C F H Peters, and is the last of his incredible haul of 48 asteroids.  Nephthys is a large, S-type main belt asteroid, and for a change is named after a character from Egyptian mythology, the daughter of Nut and Geb, and sister of Isis.



I’m going to have to do some digging on Peters, because I find it hard to believe that after 28 years of tracking the things, he doesn’t have an asteroid named after him.  I’ve found two so far named after people called Peters, and he isn’t either of them.

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Voyager 2 makes its closest approach to Neptune on August 25th, 1989.  This was the end of a bit of a purple patch for NASA.  Photographs from the outer planets had enthralled the inhabitants of this one for more than a decade, and Neptune didn’t disappoint.  Voyager 2 was able to get some great shots of the planet, including the “Great Dark Spot” which seems to have subsequently vanished. There was also time for a visit to Triton, Neptune’s volcanically active largest moon, thought to be a captured Kuiper belt object.

Neptune and Triton from the departing Voyager 2 (image credit: NASA)

Neptune and Triton from the departing Voyager 2 (image credit: NASA)

Although they didn’t know it at the time, this fly-by marked the point at which every planet in the solar system had been visited (back in the day they still had Pluto on the list).

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