September 03 – 230 Athamantis

Asteroid 230 Athamantis, discovered September 3rd 1882, was the only asteroid to be found by the German-Austrian astronomer Leo Anton Karl de Ball. It is an S-type, just over 100km across, and has a rotation period of almost exactly 24 hours.

Roman Fresco showing Phrixos and Helle (Athamantis)

Roman Fresco showing Phrixos and Helle (Athamantis)

In Greek mythology Athamantis is usually known as Helle, and she features in the story of Jason and the Argonauts. To cut a long story short she fell off a flying golden ram into the Hellespont (who hasn’t done that on a Saturday night?) and died. Her twin brother Phrixos survived the flight and presented the ram’s golden fleece to King Aeetes of Colchis, thus starting another long story.

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Asteroid 250 Bettina is one of Johann Palissa‘s. He discovered it lurking in the main belt on September 3rd, 1885. It has an absolute magnitude of 7.58, is about 80km across, and completes one full rotation every 5 hours (as usual, my statistics are severely rounded up or down; I assume nobody reading this cares much about being accurate to three decimal places).

Baroness Bettina de Rothschild

Baroness Bettina de Rothschild

Bettina gets her name from the Baroness Bettina de Rothschild (15 Feb 1858 to 24 Mar 1892), wife of the banker Albert Salomon von Rothschild. Palisa was in need of cash to fund an expedition to view the total solar eclipse of 1886, and Rothschild parted with £50 (a sum probably a lot more eye-widening then than now) for the opportunity to immortalise his wife.

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September 02 – 147 Phaedra

Discovered on September 2nd 1877 by James Craig Watson, 147 Phaedra is a bog-standard S-type (stony) asteroid, possibly with an elongated shape, in the main belt.  It takes approximately 4.8 years to get around the Sun, rotating every 5 hours as it does so.  Phaedra has a diameter of less than 70km, so determining the rotation rate by direct observation from Earth is, to say the least, difficult.  This is where light curve observations come in.  If you measure the light coming from an asteroid for long enough you end up with a collection of readings that, when plotted on a graph, repeat every so often.  What you need to do is measure the time between similar maxima or minima to give you a pretty good idea of the length of a day on the asteroid.  By the way, a rotation rate of 5 hours gives Phaedra a year of about 1700 days.  You’re going to need a bigger diary if you’re thinking of moving there.

Watson discovered 22 asteroids, but could have gone on to be one of the great rock-spotters had he not died of peritonitis at the age of 42.

Phaedra and Hippolytus (print by A G L Desnoyers of a painting by Pierre Guérin)

Phaedra and Hippolytus (print by A G L Desnoyers of a painting by Pierre Guérin)

Phaedra (from the Greek for “bright”) was married to Theseus, but fell for his illegitimate son Hippolytus (eponymous hero of a play by Euripides that I was forced to spend far too long studying in 1981) under the influence of Aphrodite, goddess of love, who was annoyed by Hippolytus’ chastity.  Basically, Phaedra makes the mistake of telling her nurse that she fancies her stepson.  The nurse tells Hippolytus; he goes ballistic; Phaedra knows things are going to get complicated, hangs herself and leaves a suicide note saying Hippolytus has raped her.  Theseus finds it, exiles his son and curses him.  Now, Theseus’ father is Poseidon, so it’s not quite the same as me or you cursing a neighbour for parking in front of our house.  In this case, as Hippolytus is fleeing into exile in his chariot, a huge bull appears from the sea, frightens his horses, and causes him to crash and be fatally wounded (he survives just long enough to be carried back on stage to make peace with his father, who has learned the truth).

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September 01 – 3 Juno and 31 Euphrosyne

1804  –  Discovery of minor planet  3 Juno. 3 Juno was, believe it or not, the third asteroid to be discovered, on September 1st 1804, by Karl L Harding. It is one if the largest S-type asteroids (15 Eunoma might be slightly larger) and approximately the 10th largest overall.

In the first few years after its discovery, wild estimates about its size led Juno, along with several others of the first group of asteroids discovered, to be classed as a planet. Their classification was downgraded to asteroid as more of them were found.

Juno can be a quite bright magnitude +7.5 at opposition, just about visible in binoculars, and has an even more eccentric orbit than Pluto. The difference between Juno’s aphelion (farthest point from the Sun) and perihelion (closest point to the Sun) is over 120 million miles. That’s greater than the distance from the Earth to the Sun.

Juno (photo: Harvard-Smithsonian Center for Astrophysics)

Juno (photo: Harvard-Smithsonian Center for Astrophysics)

Juno is, of course, named after the important Roman goddess of the same name (equivalent to the Greek Hera). Juno was the daughter of Saturn, and both sister and wife to Jupiter. She was queen if the gods, and goddess of marriage, pregnancy and childbirth. She was the mother of Mars, conceived, apparently, when she had her stomach touched with a magic flower. And if Jupiter believes that, he’ll believe anything.

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Half a century later, September 1st 1854 saw the discovery, by James Ferguson, of asteroid 31 Euphrosyne, the first asteroid to be discovered from North America. It’s a big one, possibly the fifth biggest overall; dark, C-type, with a highly inclined orbit. It also gives its name to a grouping of similar bodies.

'The Three Graces' by Canova (Euphrosyne is thought to be the one on the left). Photo: Mak Thorpe.

‘The Three Graces’ by Canova (Euphrosyne is thought to be the one on the left). Photo: Mak Thorpe.

Euphrosyne (goddess of joy), along with Thalia (good cheer) and  Aglaea (splendour), is one of the Charites, daughters of Zeus and Euronyme.

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August 16 – Asteroid 46 Hestia

Main belt asteroid 46 Hestia was discovered on August 16th 1857 from the Radcliffe Obsetvatory, Oxford, by N R Pogson. Hestia (Greek goddess of the hearth) is a “c type” body of about 124 km diameter. Pogson gave the honour of naming her to astronomer, coin collector, and veteran of the 1810-12 Siege of Cadiz, Admiral William Henry Smyth.


1873 – Discovery of asteroid 133 Cyrene.

1885 – Discovery of asteroid 249 Ilsa.

July16 – Launch of Apollo 11

July 16th 1969 is a fairly important day in spaceflight history.  It’s the day on which Neil A Armstrong, Michael Collins and Edwin “Buzz” Aldrin decided to get away from it all.  Their Saturn V rocket (SA-506), the fifth manned Apollo mission, blasted off from the Kennedy Space Centre at about half past one in the afternoon (Staffordshire Time) and may be the reason I have the vaguest recollection of my infant school gathering after dinner to watch a launch on the school television.

Launch of Apollo 11 (image credit: NASA)

Launch of Apollo 11 (image credit: NASA)

Also today, in 1990, Mark R Showalter, using old frames from Voyager 2, discovered Saturn’s walnut-shaped moon, Pan, in the Encke Gap of the A Ring (the outermost of the main bright rings).

Thanks to the Cassini probe, we now have images beyond the wildest dreams of Voyager scientists:

Pan, imaged by Cassini (credit: NASA/JPL-Caltech/Space Science Institute)

Pan, of course, invented the pan pipes. He was a pretty hot musician all round, but a little big-headed. The story goes that he challenged Apollo to a musical duel. Pan was good, but Apollo was better. Only one person listening to the contest believed that Pan had won. This was Midas (he of the golden touch). So annoyed was Apollo at this lack of musical taste that he changed Midas’ ears into something more appropriate: those of a donkey.

The Judgement of Midas (Peter Paul Rubens)

The Judgement of Midas (Peter Paul Rubens)

Now, correct me if I’m incorrect, but in today’s artistic offering, is Pan playing his own invention upside-down?

This post originally published in 2015.  Updated 2017. 

March 19 – 326 Tamara

1892   –   Asteroid 326 Tamara, discovered March 19 1892 by Johann Palisa.  It is a C-type asteroid of about 93 km wide in the main belt, named after Tamar the Great, Queen of Georgia.

Queen Tamar, and her father, George III of Georgia.

Queen Tamar, and her father, George III of Georgia.

1892  –  Asteroid 332 Siri was also discovered on March 19th 1892, but by Max Wolf at Heidelberg.  It’s a fairly small object, about 40km wide.  The origin of the name is not known, and I haven’t been able to find any likely candidates.  Part of the problem, of course, is that, as with the aforementioned Tamara, and the next on this page, Isara, the name could have been altered to fit some perceived idea of what an asteroid’s name should sound like.

1893  –  Asteroid 364 Isara was discovered by Auguste Charlois.  It is a member of the large Flora family of S-type asteroids, which may be parents of the L chondrite meteorites.  The Isère river, from which this asteroid derives its name, flows from the Alps and joins the Rhone near Valence in southern France.

1919  –  Karl Wilhelm Reinmuth discovers asteroid 911 Agamemnon, a “Greek camp” Jupiter Trojan of approximately 83 km radius (making it probably the second biggest).

Originally posted 2015. Updated 2017.


March 17 – Jim Irwin

March 17th 1930: astronaut Colonel James Benson Irwin, USAF, born in Pittsburgh PA.

James Irwin (image credit: NASA)

James Irwin (image credit: NASA)

In 1971 Irwin, Apollo 15 lunar module pilot, became the eighth man to walk on the Moon, spending over 18 hours on the surface.  He also, on his return, became one of the first people to be grounded, quite literally, for smuggling postage stamps into space.

1852  –  Asteroid 16 Psyche was discovered on March 17th 1852 by Annibale de Gasparis.  Psyche is a large asteroid, about 200 km in diameter, accounting for about 1% of the mass of the entire asteroid belt.  It’s an M-type asteroid, probably mostly nickel and iron.

Cupid and Psyche (Van Dyck)

Cupid and Psyche (Van Dyck)

Psyche is named for a mythological princess, who caught the eye of the god Cupid.  The story is told by Lucius Apuleius in The Golden Ass.

In early 2017 NASA announced plans to  send a probe to Psyche in 2023, as part of their Discovery Program, the main reason being that, as a metallic asteroid, it represents one of the few classes of objects in our neighbourhood that haven’t yet been visited.

1899  –  Saturn’s moon Phoebe discovered by American astronomer W H Pickering.  It, too, is about 200 km in diameter, and may be a captured centaur from the Kuiper belt.  We have some spectacular photographs of Phoebe following the visit of the Cassini spacecraft in 2004.

Phoebe (image credit: NASA)

Phoebe (image credit: NASA)



March 04 – Messier 85

1781  –  Messier 85, a lenticular (elliptical if you prefer) galaxy, was discovered on this day in 1781 by Pierre Méchain.  It can be found in the constellation Coma Berenices (named after the Egyptian queen Berenice II) and is about 60 million light years away, making it the northernmost galaxy in the Virgo Cluster, a collection of somewhere between 1,200 and 2,000 galaxies, on the periphery of which is our own local group.

M85 (image credit: NOAO / AURA / NSF)

M85 (image credit: NOAO / AURA / NSF)

There are hundreds of beautiful photographs of all manner of galaxies on the internet, but M85 is very under-represented by legal entities with relaxed media sharing policies, hence the above.

1861  –  Asteroid 64 Angelina discovered from Marseilles by Ernst Tempel.  Angelina is an E-type (containing enstatite) with a very high albedo (0.28) compared to many other asteroids.  It is named after an astronomical station operated by the Hungarian astronomer Franz Xaver von Zach.  For discovering Angelina (and 65 Cybele) Tempel received the ‘Lalande Prize’ from the French Académie des sciences.

1892  –  M-type (mainly metallic) main belt asteroid 325 Heidelberga was discovered today by Max Wolf.  If you’ve been following these pages closely the choice of name should come as no surprise, being the location of most, if not all, of Wolf’s discoveries. Heidelberga is reasonably large, at approximately 75 km in diameter.  Fuller details of Heidelberga’s physical and orbital characteristics can be found in the NASA JPL Small-Body Database browser.

1904  –  Birth of George Gamow, cosmologist, and early champion of the Big Bang theory.

1923  –  Birthday of Patrick Moore, amateur astronomer extraordinaire.

This post originally appeared in 2015, and was slightly updated in 2017.


December 30 – Launch of RXTE

December 30th seems to be a thin day astronomically, but I did manage to find, in 1995, the launch of the Rossi X-Ray Timing Explorer from Cape Canaveral.  Bruno Rossi, after whom the satellite was named, was the discoverer of the first source of x-rays beyond the Sun.

Artist's Impression of RXTE

Artist’s Impression of RXTE

Over a sixteen year lifespan, RXTE did exactly what its name suggests: it timed variations in emissions from x-ray sources using three experiments (a proportional counter array, theHigh Energy X-ray Timing Experiment, and an all-sky monitor).

Also today, in 1924, Edwin Hubble announced to the world that the Milky Way is not the only galaxy.  Using the 100-inch Hooker Telescope at Mount Wilson, Hubble was able to calculate the distance to Cepheid variable stars in the Andromeda Galaxy using a technique devised by Harvard astronomer Henrietta Swan Leavitt.  At the time, “spiral nebulae” were assumed to be patches of dust or gas within the Milky Way, but calculating a distance to Andromeda of approximately 860,000 light years changed the scale of the Universe for ever.


December 27 – Johannes Kepler

Today is Johannes Kepler’s birthday.

Kepler was born in Weil der Stadt, a small town near Stuttgart, on December 27th 1571, and was introduced to astronomy from an early age, whether he liked it or not, by being taken outside to witness the Great Comet of 1577, C/1577 V1, at age 6. The comet was also seen, incidentally, by Tycho Brahe, with whom Kepler would later spend some time studying at the site of Brahe’s new observatory near Prague.

Johannes Kepler

Johannes Kepler

Kepler’s works included many revolutionary (and I mean that in several ways) publications on the behaviour of planets. His Astronomia Nova, published in 1609, contained arguments in favour of a heliocentric ‘universe’, and Harmonia Mundi (“The Harmony of the World”, 1619) was the setting for his third law of planetary motion.

As well as being an influential astronomer, Kepler was also a major influence in the field of optics (possibly because his own eyesight wasn’t the best). He was the first person to explain how a telescope works; worked out how our eyes perceive depth; investigated how a pin hole camera might be used to produce pictures, and discovered total internal reflection.

Also today, globular cluster Messier 92 was discovered in 1777 by Johann Elert Bode.

M92 (Photo courtesy of the Isaac Newton Group of Telescopes, La Palma)

M92 (Photo credit: the Isaac Newton Group of Telescopes, La Palma)

M92 is located in the constellation of Hercules. It is one of the oldest and brightest globular clusters, and is about 27,000 light years from Earth.

1968 – Splashdown, south of Hawaii, of Apollo 8, following a 6 day flight that included the first Earthrise seen by humans, and the first Christmas broadcast from a craft orbiting the Moon.