April 28 – Oorter Space

We have two birthdays today.

Johann Oskar Backlund was born on April 28th 1846 in Länghem, Sweden, but after university spent his career in firstly Tartu, Estonia (part of Imperial Russia at the time) and then Pulkovi (also Russia). He was a dab hand at celestial mechanics, and became so well known in Russian astronomical circles for his work on comet 2P/Encke that Russian sources sometimes refer to it as Encke-Backlund.

Oskar Backlund
Oskar Backlund


2P/Encke is believed to be the source of the Taurid meteor shower, but Backlund was more interested in the effect it might be having on Mercury, and used the perturbations produced by the motion of the comet to predict the mass of the planet. If I had a copy of the 1961 journal Soviet Physics I might be able to share his results with you (unless they were in Russian, which seems likely).

Jan Oort was also born on this day, in 1900, in Franaker, Friesland (the Netherlands). He was mostly drawn to radio astronomy, and his day job was as a professor at the University of Lieden, under Director Ejnar Hertzsprung. Among Oort’s many career highlights were the discovery of a group of stars outside the Milky Way (the galactic halo), the calculation of how far away and in what direction lies the centre of the galaxy, and of course the idea that comets originate in what is now commonly known as the Oort Cloud, a roughly spherical region of icy planetesimals surrounding the Sun at distances of up to an almost unbelievable 50,000 AU (defining the limits of our home star’s gravitational supremacy).

Jan Oort (image: Nationaal Archief NL Fotocollectie Anefo)
Jan Oort (image: Nationaal Archief NL Fotocollectie Anefo)

1903  –  Discovery of asteroid 509 Iolanda (a.k.a. 190LR) by Max Wolf. Iolanda is an S-type main belt asteroid, and the NASA JPL Small-Body Database Browser gives it a diameter of just under 53km, an absolute magnitude of 8.40, and a rotation period (day) of 12.306 hours.

1928  –  Birth of Eugene Shoemaker, a leading light in the development of astrogeology, but mostly remembered these days as co-discoverer of comet Shoemaker-Levy 9, which famously collided with Jupiter in 1994.

1999  –  Launch of the ABRIXAS X-Ray Telescope by the German Deutsches Zentrum für Luft und Raumfahrt from the Kapustin Yar facility in Russia. The mission lasted approximately three days, thanks to an accident involving an overcharged battery.

2003  –  Galaxy Evolution Explorer (GALEX) launched.

April 26 – Discovery of Asteroid 83 Beatrix (1859)

1859  –  Birth of Italian astronomer Vincenzo Cerulli, one of the first people to suggest that Martian canals might be an optical illusion.  Cerulli discovered one asteroid, 704 Interamnia, named in honour of his home town.  Wikipedia has his birthday as April 20th, but other sources seem to agree on the 26th.

1865  –  Asteroid 83 Beatrix discovered by Annibale de Gasparis, another Italian.  It is an X-type asteroid, signifying it is part of a group of bodies with similar spectral characteristics, but not necesarily similar compositions.  This one was named for Beatrice Portinari, popularly thought to be the inspiration for the guide Beatrice in Dante’s Divine Comedy.

"Dante and Beatrice" b y Henry Holiday. (Beatrice is second from the left.)
“Dante and Beatrice” b y Henry Holiday. (Beatrice is second from the left.)

1876  –  Asteroid 163 Erigone discovered by Henri Joseph Anastase Perrotin, director of the Nice Observatory, and discoverer of six asteroids.  A rare opportunity was missed last year when Erigone occulted the first magnitude star Regulus.  This kind of happening is rarely seen from heavily populated areas, and this one would have been visible from a small track that included New York.  Unfortunately Spode’s Law came into effect and it rained heavily throughout the quarter of an hour of the event.

1884  –  Main belt asteroid 236 Honoria discovered.  Honoria is named after the sister of Emperor Valentinian III.  She gets into the history books mostly as the perpetrator of one of the worst decisions ever made: asking Attila the Hun to help her get out of a dull marriage.  Honoria was discovered by Johann Palisa.  it is about 86 km across, and is a stony S-type.

1933  –  Birth of Arno Penzias, co-discoverer with Robert Wilson of the cosmic microwave background radiation, the faint echos of the Big Bang.

1957  –  Transmission of the first episode of “The Sky At Night” by the BBC.  Under the legendary Sir Patrick Moore, it became the longest running television programme in the World to have one presenter. It’s not quite the same these days, but new presenter Maggie Aderin-Pocock (she will always be the “new” presenter to some of us) is growing on me.

1962  –  Launch of Ariel 1 (UK 1) the first British satellite.  Surprisingly, given our lackluster approach to spaceflight today, this launch made the United Kingdom the third country on the planet to have their own satellite (but we needed the Americans to launch it for us from Cape Canaveral).

April 25 – Birth of Astronomer Gérard de Vaucouleurs (1918)

Born today in 1918, Gérard de Vaucouleurs was a French astronomer who specialized in galaxies.   He is best known these days for his modification of Edwin Hubble‘s galaxy classification scheme.  De Vaucouleurs added barsrings and spiral arms to Hubble’s basic system of ellipticalspiral and lenticular galaxies.

Barred Spiral Galaxy NGC 1300 (image credit: NASA/ESA).
Barred Spiral Galaxy NGC 1300 (image credit: STScI/NASA/ESA).

In honour of Monsieur de Vaucouleurs, Today’s photo (a composite image by the Hubble Space Telescope) shows the most barred, armed, spiral galaxy I could find.  NGC 1300 is in the constellation Eridanus. It was discovered by John Herschel in 1835, and is a member of the Eridanus Cluster of about 200 galaxies.

 1848  –  The large main belt asteroid 9 Metis was discovered by Irish astronomer Andrew Graham.  It was to be the last Irish asteroid for 106 years.

1890  –  Asteroid 291 Alice, of the Flora family, discovered by Johann Palisa. Alice is roughly the shape of a giant jelly bean, at about 19 x 12 x 11 km.

1890  –  Asteroid 292 Ludovica was also discovered today, and was also one of Johann Palisa’s. Palisa was obviously smoking on April 25th, whereas Auguste Charlois was probably steaming some time afterwards, as he too discovered both asteroids, but on the 26th.

1906  –  Asteroid 599 Luisa was discovered from Taunton, Mass., by prolific American asteroid and comet hunter Joel Hastings Metcalf. The origin of the name isn’t known, but I would like to point out that Metcalf’s father was called Lewis.

1993  –  Launch of X-ray telescope Alexis (Array of Low Energy X-Ray Imaging Sensors).

April 20 – Discovery of Asteroid 532 Herculina (1904)

Asteroid 532 Herculina was discovered this very day in 1904 by Max Wolf, born 21/06/1867 in Heidelberg, studied at Heidelberg, Chair of Astronomy at Heidelberg, died 03/10/1932… Can you guess where?

Wolf discovered a phenomenal 248 asteroids, presumably in the time he saved by not bothering to leave Heidelberg. Herculina was his 9th of 1904, a year in which he was finding the critters at about one every three weeks.

Heidelberg Resident, Max Wolf.
Heidelberg Resident, Max Wolf.

With a diameter of 225 km, Herculina is one of the larger main belt asteroids, probably in the top 20. It has a nicely elliptical orbit which takes it from 2.3 to 3.26 AU from the Sun.

For a while Herculina was suspected to have a “moon”, following observations made in the 1970′s, but further studies have failed to find it. And that’s also pretty much the story of my attempt to find the location from whence was plucked the name. Herculina doesn’t appear to be anyone or anywhere in particular. Wolf’s previous asteroid, 531 Zerlina, is a character from Don Giovanni, and his next one, 539 Pamina, is from The Magic Flute. But Herculina is a mystery.

1903 – Discovery of asteroid 508 Princetonia.

April 19 – Asteroid 161 Athor (and friends)

There’s a lot going on today, and I couldn’t decide which to concentrate on, so here they all are, chronologically, in brief, beginning with . . .

1855  –  C-type main belt asteroid 35 Leukothea (a Greek sea goddess) discovered by Robert Luther.

1870  –  86 km wide M-type main belt asteroid 110 Lydia (a country in Asia Minor in the 15th and 14th centuries BC) discovered by Alphonse Borrelly.

1876  –  M-type main belt asteroid 161 Athor discovered by James Craig Watson.  Hathor, after whom this asteroid is named, was an Egyptian goddess of fertility, motherhood, beauty, and (unusually) mining.  If she looks a little odd in the picture it’s because she is often depicted as a cow.

Hathor emerging from a bed of papyrus
Hathor emerging from a bed of papyrus

1879  –  Carbonaceous asteroid 195 Eurykleia discovered by Johann Palisa.

1882  –  Asteroid 225 Henrietta discovered by Johann Palisa, and named after the wife of French astronomer Jules Janssen.

1955  –  Death of Albert Einsteinamateur violinist (among other things).  There are many witticisms attributed to Einstein, and I was tempted to put one in, probably the one concerning pretty girls and stoves, or the definition if insanity.  But trying to find a definitive translation from German, or even proving that the great man ever said them, is harder than I thought.

1971  –  Launch of Orion 1 space observatory, loaded aboard Salyut 1, the first ever space station.

1975  –  Launch of ARYABHATA, India’s first satellite (launched on their behalf by the Soviet Union).


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.  I have been completely unable to find any picture or photograph of Luther, which is annoying.

1756  –  Death of Jacques Cassini.

1972  –  Launch of Apollo 16.

April 15 – Discovery of Asteroid 43 Ariadne (1857)

Today’s birthday is Friedrich Georg Wilhelm Von Struve.  Von Struve was born in Holstein (now in Germany, but then part of the united kingdom of Denmark-Norway) on April 15, 1629.

He was a keen observer of double stars, and published measurements of over 2,000 in his Stellarum duplicium et multiplicium mensurae micrometricae.  Despite this he still found the time to father 18 children to two wives.

1857  –  Asteroid 43 Ariadne was discovered today in 1857 by Sir Robert Norman Podgson, KBE.  Ariadne was the second of eight asteroids he discovered.  It is also the name of a Hawaiian Goose I adopted at the Wildfowl & Wetland Trust’s Martin Mere site in Lancashire some years ago, but that’s neither here nor there.

'Bacchus and Ariadne' by Titian.
‘Bacchus and Ariadne’ by Titian.

April 12 – Discovery of Asteroid 10 Hygiea (1849)

1849  –  Asteroid 10 Hygiea was discovered today by Annibale de Gasparis.  Hygiea has a family of asteroids named after it (the Hygiea family, obviously) and is the fourth largest object in the Asteroid Belt, with a diameter of about 530 km.  Unfortunately it is also quite dark, which made it difficult to see from down here in the 1840s, so despite being the fourth largest, it is only designated as number 10, because some smaller, brighter asteroids were spotted first.

The name de Gasparis decided on for the first of his nine asteroids was Igea Bourbonica (Bourbonica is an homage to the ruling family of Sicily, rather than the brown biscuits he may or may not have nibbled during his observations).  The Bourbonica bit was dropped within a few years of discovery, like the soggy end of some bourbon dunked too long by a distracted astronomer, splashing in the dark tea of history, never to be found by the spoon of fame. (It’s been a long day.)

Princess Maria Antonietta of Buorbon-Two Sicilies
Princess Maria Antonietta of Buorbon-Two Sicilies

Hygieia (I let an extra “i” creep in there because there are various spellings) was the goddess of health and cleanliness, and daughter of Asclepius, the Greek god of medicine.  One of her sisters, the goddess of “universal remedy” also persists to this day in the English language: Panacea.

1981  –  First flight of the shuttle Columbia (STS-1) from the Kennedy Space Centre.  Columbia completed 23 missions before the disaster of 2003.    STS-1 was the first orbital shuttle mission, lasting two and a bit days.  She only carried a two-man crew, commander John W Young and pilot Robert L Crippen.

During mission STS-1, Columbia, the most complicated machine on the planet,  attained an orbital altitude of 166 miles, 60 miles short of the total length of wire it contained.

1817  –  Death of Charles Messier, comet hunter.

1851  –  Birth of Edward Maunder, sunspot spotter.

1961  –  And finally today we celebrate the launch of Vostok 1 from the Baikonur Cosmodrome, taking Yuri Gagarin on the first and shortest ever orbital manned spaceflight (once round the block: 108 minutes). As with the launch of Sputnik 1 in 1957, this was another victory for the Soviet space program over NASA.  I blame monkeys for the delays in the West.  NASA tended to prefer monkeys for their test flights, while the Russians used dogs.  Monkeys are really hard to control, so the Americans must have wasted ages trying to train them to sit still.  If you have a rhesus monkey and a dog, and you tell them both to stay where they are, one of them is going to wander off looking for bananas, while the other waits as long as is necessary for you to produce a biscuit.  I’ll let you decide which is which.

March 16 – Caroline Herschel

Caroline Herschel was the sister of the more famous William.  She was born this day in 1750 in the German town of Hannover, but moved to London in 1772 to join her elder brother, after which she became a lean, mean, comet hunting machine, finding eight of them in eleven years.  She also discovered an impressive clutch of deep sky objects, mostly open clusters, and was awarded the Gold Medal by the Royal Astronomical Society.  After William’s death she moved back to Hannover, where she died in 1848.

Caroline Herschel
Caroline Herschel

Herschel wasn’t the tallest astronomer in history, and at 4 foot 3 inches she might possibly be the shortest person ever to find a comet (I need to check up on that).  Her diminutive stature was caused by a bout of typhus at the age of ten.  Her father sounds less than doting, and is reported to have told his fifth child that, because of the deformity caused by this illness, she would never marry.  Nice man.

March 06 – birth of Joseph von Fraunhofer (1787)

Today, in 1787 in Bavaria, Joseph von Fraunhofer, inventor of the spectroscope, and discoverer of the Sun’s absorption lines, was born.

Von Fraunhofer.
Von Fraunhofer.

Unfortunately for the worlds of optics and astronomy, Fraunhofer died on June 7th, 1826, at the young age of 39 (early death was an occupational hazard for glassmakers in those days due to the poisonous heavy metal vapours associated with the craft).

Fraunhofer lines are dips in the intensity of starlight that are now known to coincide with absorption of energy by certain elements in the atmosphere of a star. On a visible spectrum, the lack of energy shows up as dark lines.