January 10: Eugène Joseph Delporte

The Amor group of asteroids.

Eugène Joseph Delporte

January 10, 1872 – October 19, 1955

Eugène Joseph Delporte was a Belgian astronomer.

He discovered a total of sixty-six asteroids. Notable discoveries include 1221 Amor (which lent its name to the Amor asteroids) and the Apollo asteroid 2101 Adonis. He discovered or co-discovered some comets as well, including periodic comet 57P/du Toit-Neujmin-Delporte.

He worked in the Observatoire Royal de Belgique (Belgian Royal Observatory), situated in the town of Uccle (after which the asteroid 1276 Ucclia is named).

In 1930 he fixed the modern boundaries between all of the constellations in the sky, along lines of right ascension and declination for the epoch B1875.0.

The Lunar crater Delporte is named in his honor.

January 10: Simon Marius

The Astronomy Compendium: January 10

December 4: Wilhelm Tempel

Ernst Wilhelm Leberecht Tempel

December 4, 1821 – March 16, 1889

Wilhelm Tempel, was a German astronomer who worked in Marseille until the outbreak of the Franco-Prussian War in 1870, then later moved to Italy.

He was a prolific discoverer of comets, discovering or co-discovering 21 in all, including Comet 55P/Tempel-Tuttle, now known to be the parent body of the Leonid meteor shower, and 9P/Tempel, the target of the NASA probe Deep Impact in 2005.

Other periodic comets that bear his name include 10P/Tempel and 11P/Tempel-Swift-LINEAR.

The asteroid 3808 Tempel and the Lunar crater Tempel are named in his honor.

October 11: Heinrich Olbers

Heinrich Wilhelm Matthäus Olbers

October 11, 1758 – March 2, 1840

Heinrich Olbers was a German physician and astronomer.

Olbers was born in Arbergen, near Bremen, and studied to be a physician at Göttingen. After his graduation in 1780, he began practicing medicine in Bremen, Germany. At night he dedicated his time to astronomical observation, making the upper story of his home into an observatory. He also devised the first satisfactory method of calculating cometary orbits.

On March 28, 1802, Olbers discovered and named the asteroid Pallas. Five years later, on March 29, 1807, he discovered the asteroid Vesta, which he allowed Carl Friedrich Gauss to name. As the word "asteroid" was not yet coined, the literature of the time referred to these minor planets as planets in their own right. He proposed that the asteroid belt, where these objects lay, was the remnants of a planet that had been destroyed. The current view of most scientists is that tidal effects from the planet Jupiter disrupt the formation of planets in the asteroid belt.

On March 6, 1815, Olbers also discovered a periodic comet, now named after him (formally designated 13P/Olbers).

Olbers' paradox, described by him in 1823 (and then reformulated in 1826), states that the darkness of the night sky conflicts with the supposition of an infinite and eternal static universe.

In 1827, he was elected a foreign member of the Royal Swedish Academy of Sciences.

The crater Olbers on the Moon, the asteroid 1002 Olbersia and a 200-km-diameter dark albedo feature on Vesta's surface are all named in his honor.

October 8: Ejnar Hertzsprung

Ejnar Hertzsprung

October 8, 1873 - October 21, 1967

Ejnar Hertzsprung was a Danish chemist and astronomer.

In the period 1911-1913, together with Henry Norris Russell, he developed the Hertzsprung-Russell diagram.

In 1913 he determined the distances to several Cepheid variable stars by statistical parallax, and was thus able to calibrate the relationship discovered by Henrietta Leavitt between Cepheid period and luminosity. In this determination he made a mistake, possibly a slip of the pen, putting the stars 10 times too close. He used this relationship to estimate the distance to the Small Magellanic Cloud.

From 1919 to 1946 Hertzsprung worked at Leiden Observatory in The Netherlands, from 1937 as director. Perhaps his greatest contribution to astronomy was the development of a classification system for stars to divide them by spectral type, stage in their development, and luminosity. The "Hertzsprung-Russell Diagram" was used for many years as a classification system to explain stellar types and evolution.

He discovered two asteroids, 1627 Ivar (25 September 1929) and 1702 Kalahari (7 July 1924)

Hertzsprung received the Gold Medal of the Royal Astronomical Society in 1929 and the Bruce Medal in 1937.

The Lunar crater Hertzsprung and the asteroid 1693 Hertzsprung are named in his honor.

October 1: Charles Edward Adams

Dr Charles Edward Adams (left) reading an anemometer.

Charles Edward Adams

October 1, 1870 - October 31, 1945

Charles Edward Adams was a University lecturer, surveyor, astronomer and seismologist. He was born at Lawrence, Otago, New Zealand.

Adams was awarded an MSc from the University of New Zealand in 1909 and by 1910 was chief computer at the head office of the Lands and Survey Department. The techniques he devised during this period for the prediction of tides were, with few modifications, employed in New Zealand until 1924. In 1911, while continuing to discharge his duties in the department, he was appointed astronomical observer at Wellington. Early the following year he became government astronomer. He spent 1915 as Martin Kellogg fellow at the Lick Observatory, California, then returned to a full-time position as government astronomer in the Internal Affairs Department. He was awarded a DSc from the University of New Zealand in 1915 for a thesis entitled Harmonic analysis of tidal observations and predictions of tides.

It was Adams's work in astronomy that identifies him as one of New Zealand's important scientists. He developed methods of computation of planetary ephemerides and cometary orbits and made observations of sunspots, variable stars, planets and auroras. In 1922 he accompanied the Lick Observatory solar eclipse expedition to Western Australia and in 1930 led an eclipse expedition to Niuafo'ou, in the Tongan group. He pioneered the use of cinematography for astronomical timing. The camera he devised for photographing the Moon against its background stars, so that accurate longitudes and lunar positions could be gauged, forms the basis of the standard modern instrument.

As government astronomer Adams was in charge of the Hector Observatory and responsible for maintaining accurate time for scientific and civil purposes such as navigation.

He was the founder and president of the New Zealand Astronomical Society (now the Royal Astronomical Society of New Zealand), an associate in astronomy at Yale University and a fellow of the Royal Astronomical Society, London. He was also very active in the establishment of the Carter Observatory, believing that the capital city was entitled to an up-to-date observatory and telescope.

An asteroid discovered in 1985 by astronomers at the Mt John University Observatory, Lake Tekapo, was named 3305 Ceadams in his honour.

Source:

Smith, Warwick D. 'Adams, Charles Edward 1870 - 1945'. Dictionary of New Zealand Biography, updated 22 June 2007

http://www.dnzb.govt.nz/

September 23: Johann Encke

Johann Franz Encke

September 23, 1791 – August 26, 1865

Johann Franz Encke was a German astronomer, born in Hamburg. He is sometimes confused with Karl Ludwig Hencke, another German astronomer.

Encke studied mathematics and astronomy from 1811 at the University of Göttingen under Carl Friedrich Gauss; but he enlisted in the Hanseatic Legion for the campaign of 1813–1814, and became lieutenant of artillery in the Prussian army in 1815. Having returned to Göttingen in 1816, he was at once appointed by Bernhardt von Lindenau as his assistant in the observatory of Seeberg near Gotha.

There he completed his investigation of the comet of 1680, for which the Cotta prize was awarded to him in 1817; he correctly assigned a period of 71 years to the comet of 1812. That comet is now called 12P/Pons-Brooks.

Following a suggestion by Jean-Louis Pons, who suspected one of the three comets discovered in 1818 to be the same one already discovered by him in 1805, Encke began to calculate the orbital elements of this comet. At this time, all the known comets only had an orbital period of seventy years and more, where the aphelion is far beyond the orbit of Uranus. The most famous comet of this family was Comet Halley with its period of seventy-six years. Therefore the orbit of the comet discovered by Pons was a sensation, because his orbit was found to have a period of 3.3 years, therefore the aphelion had to be within the orbit of Jupiter. Encke predicted its return for 1822, but this return was only observable from the southern hemisphere and was seen by Carl Ludwig Christian Rümker from Australia. The comet was also identified with the one seen by Pierre Méchain in 1786 and by Caroline Herschel in 1795.

Encke sent his calculations as a note to Gauss, Olbers, and Bessel. His former mathematics professor published this note and Encke became famous as the discoverer of the short periodic comets. The first object of this family, the Encke comet, was named after him and so it is one of the few comets not named after the discoverer, but after the one who calculated the orbit. Later this comet was identified as the origin of the Taurids meteor showers.

The importance of the predicted return based on the calculation by Encke was rewarded by the Royal Astronomical Society in London by presenting their Gold Medal to him in 1824.

In 1837, Encke described a broad variation in the brightness of the A Ring of Saturn. The Encke Division was later named in honor of his observations of Saturn's rings.

Twice, in 1824 and 1830, he received the Gold Medal of the Royal Astronomical Society.

The crater Encke on the Moon, the asteroid 9134 Encke and the Encke gap of Saturn's rings are named in his honor.

July 13: Heinrich Louis d'Arrest

Heinrich Louis d'Arrest

July 13, 1822 – June 14, 1875

Heinrich Louis d'Arrest was a Prussian astronomer, born in Berlin.

While still a student at the University of Berlin, d'Arrest was party to Johann Gottfried Galle's search for Neptune. On September 23, 1846, he suggested that a recently drawn chart of the sky, in the region of Urbain Le Verrier's predicted location, could be compared with the current sky to seek the displacement characteristic of a planet, as opposed to a stationary star. Neptune was discovered that very night.

D'Arrest's later work at the Leipzig Observatory led him, in 1851, to the discovery of the comet named for him (formally designated 6P/d'Arrest). He also studied asteroids (he discovered 76 Freia) and nebulae.

He won the Gold Medal of the Royal Astronomical Society in 1875.

The crater D'Arrest on the Moon is named after him, as well as a crater on the Martian satellite Phobos and the asteroid 9133 d'Arrest.

July 7: Giuseppe Piazzi

Giuseppe Piazzi

July 7, 1746 - July 22, 1826

Giuseppe Piazzi was an Italian mathematician and astronomer. He discovered the asteroid Ceres and established an observatory at Palermo, now the Osservatorio Astronomico di Palermo – Giuseppe S. Vaiana.

In March 1781 Piazzi moved to Palermo as lecturer in Mathematics at the University of Palermo. He kept this position until 19 January 1787, when he became Professor of Astronomy. Almost at the same time he was granted permission to spend two years in Paris and London in order to undergo some practical training in astronomy and also to get some instruments to be specially built for the Palermo Observatory, whose foundation he was in charge of. In the period spent abroad, from 13 March 1787 until the end of 1789, Piazzi became acquainted with the major French and English astronomers of his time and was able to have the famous altazimuthal circle made by Jesse Ramsden, one of the most skilled instrument-makers of the 18th century. The circle was the most important instrument of the Palermo Observatory, whose official foundation took place on 1 July 1790. In 1817 King Ferdinand put Piazzi in charge of the completion of the Capodimonte (Naples) Observatory, naming him General Director of the Naples and Sicily Observatories.

He supervised the compilation of the Palermo Catalogue of stars, containing 7,646 star entries with unprecedented precision, including the star names "Garnet Star" from Herschel, and the original Rotanev and Sualocin. The work on this catalogue was started in 1789, enabling Piazzi and collaborators to observe the sky methodically. The catalogue wasn't finished for first edition publication until 1803.

Spurred by the success discovering Ceres, and in the line of his catalogue program, Piazzi studied the proper motions of stars in order to find parallax measurement candidates. One of them, 61 Cygni, was specially appointed as a good candidate for measuring a parallax, which was later performed by Friedrich Wilhelm Bessel. The star system 61 Cygni is sometimes still called variously Piazzi's Flying Star and Bessel's Star.

Piazzi discovered Ceres, today known as the largest member of the asteroid belt. On January 1, 1801, Piazzi discovered a "stellar object" that moved against the background of stars. At first he thought it was a fixed star, but once he noticed that it moved, he became convinced it was a planet, or as he called it, "a new star".

In spite of his assumption that it was a planet, he took the conservative route and announced it as a comet. In a letter to astronomer Barnaba Oriani of Milan he made his suspicions known in writing:

"I have announced this star as a comet, but since it is not accompanied by any nebulosity and, further, since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet. But I have been careful not to advance this supposition to the public."

He was not able to observe it long enough as it was soon lost in the glare of the Sun. Unable to compute its orbit with existing methods, the renowned mathematician Carl Friedrich Gauss developed a new method of orbit calculation that allowed astronomers to locate it again. After its orbit was better determined, it was clear that Piazzi's assumption was correct and this object was not a comet but more like a small planet. Coincidentally, it was also almost exactly where the Titius-Bode law predicted a planet would be.

Piazzi named it "Ceres Ferdinandea," after the Roman and Sicilian goddess of grain and King Ferdinand IV of Naples and Sicily. The Ferdinandea part was later dropped for political reasons. Ceres turned out to be the first, and largest, of the asteroids existing within the Asteroid Belt. Ceres is today called a dwarf planet.

In 1871, a memorial statue of Piazzi sculpted by Costantino Corti was dedicated in the main plaza of his birthplace, Ponte. In 1923, the 1000th asteroid to be numbered was named 1000 Piazzia in his honor. The lunar crater Piazzi was named after him in 1935. More recently, a large albedo feature, probably a crater, imaged by the Hubble Space Telescope on Ceres, has been informally named Piazzi.

June 21: Maximilian Wolf

Maximilian Wolf

June 21, 1863 – October 3, 1932

Maximilian Franz Joseph Cornelius Wolf was a German astronomer, a pioneer of astrophotography.

He was born in Heidelberg, Germany. In 1888 he was awarded a Ph.D. by the University of Heidelberg, and joined the staff of that institution in 1890.

Working at Landessternwarte Heidelberg-Königstuhl, he discovered more than 200 asteroids with the Bruce double-astrograph since 1891. The first one, 323 Brucia, was named after Catherine Wolfe Bruce, who had donated $10,000 for the construction of the telescope. He pioneered the use of astrophotographic techniques to automate the discovery of asteroids, as opposed to older visual methods, as a result of which asteroid discovery rates sharply increased. In time-exposure photographs, asteroids appear as short streaks due to their planetary motion with respect to fixed stars.

Among his many discoveries was 588 Achilles (the first Trojan asteroid) in 1906, as well as two other Trojans: 659 Nestor and 884 Priamus. He also discovered 887 Alinda in 1918, which is now recognized as an Earth-crossing Amor asteroid (or sometimes classified as the namesake of its own Alinda family). Shortly after his last discovery (on February 6, 1932), his record 248 discoveries were beaten by his pupil Karl Wilhelm Reinmuth, on July 24, 1933.

He also discovered or co-discovered some comets, including 14P/Wolf and 43P/Wolf-Harrington, and four supernovae: SN 1895A (a.k.a. VW Vir), 1909A (a.k.a. SS UMa), 1920A, and 1926A (the latter co-discovered by Reinmuth).

He also discovered Wolf 359, a red dwarf that is one of the nearest stars to our solar system. Note that Wolf-Rayet stars were co-discovered by French astronomer Charles Wolf and not by him.

In 1910 Wolf proposed to the Carl Zeiss optics firm the creation of a new instrument, now known as the planetarium. World War I intervened before this could be developed, but the Zeiss company returned to this after peace was restored, and the first successful planetarium was completed in 1923.

June 4: Baron Franz Xaver von Zach

Baron Franz Xaver von Zach

June 4, 1754 – September 2, 1832

Baron Franz Xaver von Zach was a Hungarian astronomer born at Pest.

He served for some time in the Austrian army, and afterwards lived in London from 1783 to 1786 as tutor in the house of the Saxon minister, Count Brühl. In 1786 he was appointed by Ernest II, Duke of Saxe-Gotha-Altenburg director of the new observatory on Seeberg hill at Gotha, which was finished in 1791. At the close of the 18th century, he organised a group of twenty-four astronomers to prepare for a systematic search for the "missing planet" predicted by the Titius-Bode law between Mars and Jupiter. Ironically, Ceres was discovered by accident just as the search was getting underway. From 1806 Zach accompanied the duke's widow on her travels in the south of Europe. He died in Paris in 1832.

Zach published Tables of the Sun and numerous papers on geographical subjects, particularly on the geographical positions of many towns and places, which he determined on his travels with a sextant.

His principal importance was as editor of three scientific journals of great value: Allgemeine Geographische Ephemeriden (4 vols., Gotha, 1798-1799), Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde (28 vols., Gotha, 1800-1813, from 1807 edited by Bernhard von Lindenau), and Correspondance astronomique, geographique, hydrographique, et statistique (Genoa, 1818-1826, 14 vols., and one number of the 15th, the suppression of which was instigated by the Jesuits).

He was elected a member of the Royal Swedish Academy of Sciences in 1794. Asteroid 999 Zachia and the crater Zach on the Moon are named after him, while asteroid 64 Angelina is named after an astronomical station he set up near Marseille.

May 12: John Russell Hind

John Russell Hind

May 12, 1823 – December 23, 1895

John Hind was an English astronomer. Some sources give his name as John Russel Hind with only one "L". However, 19th century British astronomical magazines consistently spell his name with two "L"s.

Hind was born in 1823 in Nottingham. At age 17 he went to London to serve an apprenticeship as a civil engineer, but through the help of Charles Wheatstone he left engineering to accept a position at the Royal Greenwich Observatory under George Biddell Airy. Hind remained there from 1840 to 1844, at which time he succeeded W. R. Dawes as director of the private observatory of George Bishop. In 1853 Hind became Superintendent of the Nautical Almanac, a position he held until 1891.

Hind is notable for being one of the early discoverers of asteroids. He also discovered and observed the variable stars R Leporis, U Geminorum, and T Tauri (also called Hind's Variable Nebula), and discovered the variability of μ Cephei. Hind discovered Nova Ophiuchi 1848 (V841 Ophiuchi), the first nova of modern times (since the supernova SN 1604).

Hind's naming of the asteroid 12 Victoria caused some controversy. At the time, asteroids were not supposed to be named after living persons. Hind somewhat disingenuously claimed that the name was not a reference to Queen Victoria, but the mythological figure Victoria.

Hind was a Fellow of the Royal Society (1851) and was awarded the Gold Medal of the Royal Astronomical Society (1853). The Lunar crater Hind and the asteroid 1897 Hind are named in his honor.