September 30: Michael Maestlin

Michael Maestlin

September 30, 1550 - October 20, 1631

Michael Maestlin was a German astronomer and mathematician, known for being the mentor of Johannes Kepler.

Maestlin studied theology, mathematics, and astronomy at the Tübinger Stift in Tübingen, a town in Württemberg. In 1580 he became a Professor of mathematics, first at the University of Heidelberg, then at the University of Tübingen were he taught for 47 years from 1583. In 1582 Maestlin wrote a popular introduction to astronomy.

Among his students was Johannes Kepler (1571-1630). Although he primarily taught the traditional geocentric Ptolemaic view of the solar system, Maestlin was also one of the first to accept and teach the heliocentric Copernican view. Maestlin corresponded with Kepler frequently and played a sizable part in his adoption of the Copernican system. Galileo Galilei's adoption of heliocentrism was also attributed to Maestlin .

The first known calculation of the (inverse) golden ratio as a decimal of "about 0.6180340" was written in 1597 by Maestlin in a letter to Kepler.

Maestlin catalogued the Pleiades cluster on December 24, 1579. Eleven stars in the cluster were recorded by Maestlin, and possibly as many as fourteen were observed. He also observed the occultation of Mars by Venus on October 3, 1590, at Heidelberg.

In Jules Verne's Cinq semaines en ballon (Five Weeks in a Balloon) the character of Joe, the manservant, is described as enjoying, "in common with Moestlin, Kepler's professor, the rare faculty of distinguishing the satellites of Jupiter with the naked eye, and of counting fourteen of the stars in the group of Pleiades, the remotest of them being only of the ninth magnitude."

The Lunar crater Maestlin, the Lunar rille Rimae Maestlin and the asteroid 11771 Maestlin, discovered in 1973, are named in his honor.

September 29: Gustav Mie

Gustav Adolf Feodor Wilhelm Ludwig Mie

September 29, 1869 – February 13, 1957

Gustav Mie was a German physicist.

Mie was born in Rostock. From 1886 he studied mathematics and physics at the University of Rostock. In addition to his major subjects, he also attended lectures in chemistry, zoology, geology, mineralogy, astronomy as well as logic and metaphysics. In 1889 he continued his studies at the University of Heidelberg and received a doctorate degree in mathematics at the age of 22.

In 1897 he got his Habilitation at the University of Göttingen in theoretical physics and in 1902 became extraordinary professor for theoretical physics at the University of Greifswald. In 1917 he became full professor for experimental physics at Martin Luther University of Halle-Wittenberg. In 1924 he became Professor at the University of Freiburg, where he worked up to his retirement in 1935.

During his Greifswald years he worked on the computation of scattering of an electromagnetic wave by a homogeneous dielectric sphere, which was published in 1908 under the title of “Contributions to the optics of turbid media, particularly of colloidal metal solutions” in Annalen der Physik. The term Mie scattering is still related to his name. Using Maxwell's electromagnetic theory applied to spherical Gold particles Gustav Mie provided a theoretical treatment of plasmon resonance absorption of Gold colloids. The sharp absorption bands depend on the particle size and explain the change in colour that occurs as the size of the colloid nanoparticles is increased from 20 to 1600 nm. He wrote further important contributions to electromagnetism and also to relativity theory.

In addition he was employed on measurements units and finally developed his Mie system of units in 1910 with the basic units Volt, Ampere, Coulomb and Second (VACS-system).

A crater on Mars was named in his honor and a building of the University of Freiburg carries his name.

September 28: Ismaël Bullialdus

Ismaël Bullialdus

September 28, 1605 - November 25, 1694

Ismaël Bullialdus was a French astronomer. He was born Ismaël Boulliau in Loudun, Vienne, France, the first surviving son to Ismaël Boulliau, a notary by profession and amateur astronomer.

Bullialdus was a friend of Pierre Gassendi, Christiaan Huygens, Marin Mersenne, and Blaise Pascal, and an active supporter of Galileo Galilei and Nicolaus Copernicus. It is for his astronomical and mathematical works that he is best known. Chief among them is his Astronomia philolaica, (published 1645). In this work he strongly supported Kepler's hypothesis that the planets travel in elliptical orbits around the Sun, but argued against the physical theory the latter had proposed to explain them. In particular, he objected to Kepler's proposal that the strength of the force exerted on the planets by the Sun would decrease in inverse proportion to their distance from it. He argued that if such a force existed it would instead have to follow an inverse-square law:

As for the power by which the Sun seizes or holds the planets, and which, being corporeal, functions in the manner of hands, it is emitted in straight lines throughout the whole extent of the world, and like the species of the Sun, it turns with the body of the Sun; now, seeing that it is corporeal, it becomes weaker and attenuated at a greater distance or interval, and the ratio of its decrease in strength is the same as in the case of light, namely, the duplicate proportion, but inversely, of the distances that is, 1/d².

However, Bullialdus did not believe that any such force did in fact exist. After writing the above-quoted passage, he then went on to write:

... I say that the Sun is moved by its own form around its axis, by which form it was ignited and made light, indeed I say that no kind of motion presses upon the remaining planets ... indeed [I say] that the individual planets are driven round by individual forms with which they were provided ...

In his Principia Mathematica of 1687, Isaac Newton acknowledged that Bullialdus's determination of the sizes of the planets' orbits ranked with Kepler's as the most accurate then available.

Bullialdus was one of the earliest members of the Royal Society, London, having been elected on April 4, 1667, seven years after its founding.

The Lunar crater Bullialdus is named in his honor.

September 27: Martin Ryle

Martin Ryle

September 27, 1918 - October 14, 1984

Sir Martin Ryle was an English radio astronomer who developed revolutionary radio telescope systems (e.g. aperture synthesis) and used them for accurate location and imaging of weak radio sources. In 1946 Ryle and Vonberg were the first people to publish interferometric astronomical measurements at radio wavelengths, although it is claimed that Joseph Pawsey from the University of Sydney had actually made interferometric measurements earlier in the same year. With improved equipment, Ryle observed the most distant known galaxies in the universe at that time. He was the first Professor of Radio Astronomy at the University of Cambridge, and founding director of the Mullard Radio Astronomy Observatory. He was Astronomer Royal from 1972 to 1982.

Ryle and Antony Hewish shared the Nobel Prize for Physics in 1974, the first Nobel prize awarded in recognition of astronomical research.

The focus of early work in Cambridge was on radio waves from the Sun. Ryle's interest quickly shifted to other areas, however, and to explore those he decided early on that the Cambridge group should develop new observing techniques. As a result, Ryle was the driving force in the creation and improvement of astronomical interferometry and aperture synthesis, which have contributed immensely to upgrading the quality of radio astronomical data. In 1946 he built the first multi-element astronomical radio interferometer.

He guided the Cambridge radio astronomy group in the production of several important radio source catalogues. For example, the Third Cambridge Catalogue of Radio Sources (3C) 1959 helped lead to the discovery of the first quasi-stellar object (quasar).

While serving as university lecturer in physics at Cambridge from 1948 to 1959, Ryle became director of the Mullard Radio Astronomy Observatory 1957, and professor of radio astronomy in 1959. He was elected a fellow of the Royal Society in 1952, was knighted in 1966, and succeeded Sir Richard Woolley as Astronomer Royal (1972-82).

Martin Ryle was undoubtedly one of the great astronomers of the 20th Century. He was sometimes considered difficult to work with - in fact he often worked in an office at the Mullard Radio Astronomy Observatory to avoid disturbances from other members of the Cavendish Laboratory and to avoid getting into heated arguments, as Ryle had a hot temper. Ryle worried that Cambridge would lose its standing in the radio astronomy community as other radio astronomy groups had much better funding, so he encouraged a certain amount of secrecy about his aperture synthesis methods in order to keep an advantage for the Cambridge group.

Ryle received the Hughes Medal (1954), the Gold Medal of the Royal Astronomical Society (1964), the Henry Draper Medal (1965), the Royal Medal (1973), the Bruce Medal (1974), and the Nobel Prize in Physics (1974). The Ryle Telescope at Mullard Radio Astronomy Observatory is named in his honor.

September 26: Christopher Hansteen

Christopher Hansteen

September 26, 1784 – April 11, 1873

Christopher Hansteen was a Norwegian geophysicist, astronomer and physicist.

In 1807 Hansteen began the inquiries in terrestrial magnetism with which his name is especially associated. His first scientific publication was printed in Journal de Physique, following a contest on magnetic axes created in 1811 by the Royal Danish Academy of Sciences and Letters. In 1813 he was given a research scholarship by the recently established (in 1811) Royal Frederick University in Christiania, with a promise of a future academic position.

Working as a lecturer from 1814, in 1816 Hansteen was promoted to professor of astronomy and applied mathematics. He was the editor of the official Norwegian almanac from 1815, manager of the city astronomical observatory from the same year and co-director of the Norwegian Mapping and Cadastre Authority from 1817. In 1819 he published a volume of researches on terrestrial magnetism, which was translated into German under the title of Untersuchungen über den Magnetismus der Erde, with a supplement containing Beobachtungen der Abweichung und Neigung der Magnetnadel and an atlas. By the rules there framed for the observation of magnetical phenomena Hansteen hoped to accumulate analyses for determining the number and position of the magnetic poles of the Earth. In 1822 he co-founded Norway's first journal on natural sciences, Magazin for Naturvidenskaberne. He sat as editor-in-chief for eight years.

In the course of his research he travelled over Finland and the greater part of his own country; and from 1828 to 1830 he undertook, in company with Georg Adolf Erman and with the cooperation of Russia, a government-funded mission to Western Siberia. Shortly after the return of the mission, in 1833 Hansteen moved with his family into the observatory, which was created from drawings by the architect Christian Heinrich Grosch. A magnetic observatory was added in 1839.

From 1835 to 1838 he published textbooks on geometry and mechanics, largely a reaction to his former research assistant Bernt Michael Holmboe's textbooks. In 1842 Hansteen wrote his Disquisitiones de mutationibus, quas patitur momentum acus magneticae. He also contributed various papers to different scientific journals, especially Magazin for Naturvidenskaberne.

Hansteen was a member of the Royal Norwegian Society of Sciences and Letters from 1818 and of the Norwegian Academy of Science and Letters from 1857, as well as several learned societies in other countries, including the Royal Swedish Academy of Sciences (1822). He was a member of the board of the Royal Norwegian Society for Development for many years, and also chaired the board of the Norwegian National Academy of Craft and Art Industry.

The crater Hansteen and the mountain Mons Hansteen on the Moon are named in his honor.

September 25: Ole Rømer

Ole Christensen Rømer

September 25, 1644 – September 19, 1710

Ole Rømer was a Danish astronomer who in 1676 made the first quantitative measurements of the speed of light.

Ole Rømer went to the University of Copenhagen in 1662, at which his mentor was Rasmus Bartholin. Rømer was given every opportunity to learn mathematics and astronomy using Tycho Brahe's astronomical observations, as Bartholin had been given the task of preparing them for publication.

After studies in Copenhagen, Rømer joined the observatory of Uraniborg on the island of Hven, near Copenhagen, in 1671. Over a period of several months, Jean Picard and Rømer observed about 140 eclipses of Jupiter's moon Io, while in Paris Giovanni Domenico Cassini observed the same eclipses. By comparing the times of the eclipses, the difference in longitude of Paris to Uranienborg was calculated.

Cassini had observed the moons of Jupiter between 1666 and 1668, and discovered discrepancies in his measurements that, at first, he attributed to light having a finite speed. In 1672 Rømer went to Paris and continued observing the satellites of Jupiter as Cassini's assistant. Rømer added his own observations to Cassini's and observed that times between eclipses (particularly those of Io) got shorter as Earth approached Jupiter, and longer as Earth moved farther away. Cassini published a short paper in August 1675 where he states: This second inequality appears to be due to light taking some time to reach us from the satellite; light seems to take about ten to eleven minutes to cross a distance equal to the half-diameter of the terrestrial orbit.

Oddly, Cassini seems to have abandoned this reasoning, which Rømer adopted and set about buttressing in an irrefutable manner, using a selected number of observations performed by Picard and himself between 1671 and 1677. Rømer presented his results to the French Academy of Sciences, and it was summarised soon after by an anonymous reporter in a short paper, Démonstration touchant le mouvement de la lumière trouvé par M. Roemer de l'Académie des sciences, published 7 December 1676 in the Journal des sçavans. Unfortunately the paper bears the stamp of the reporter failing to understand Rømer's presentation, and as the reporter resorted to cryptic phrasings to hide his lack of understanding, he obfuscated Rømer's reasoning in the process. Unfortunately Rømer himself never published his results.

Rømer never gave a value for the speed of light. However, many others calculated a speed from his data, the first being Christiaan Huygens; after corresponding with Rømer and eliciting more data.

Rømer's view that the velocity of light was finite was not fully accepted until measurements of the so-called aberration of light were made by James Bradley in 1727.

In 1809, again making use of observations of Io, but this time with the benefit of more than a century of increasingly precise observations, the astronomer Jean Baptiste Joseph Delambre reported the time for light to travel from the Sun to the Earth as 8 minutes and 12 seconds. Depending on the value assumed for the astronomical unit, this yields the speed of light as just a little more than 300,000 kilometres per second.

A plaque at the Observatory of Paris, where the Danish astronomer happened to be working, commemorates what was, in effect, the first measurement of a universal quantity made on this planet.

The Lunar crater Römer is named in his honor.

September 24: Charlotte Sitterly

Charlotte Emma Moore Sitterly

September 24, 1898 – March 3, 1990

Charlotte Moore Sitterly was an American astronomer.

Charlotte Moore was born in Ercildoun, Pennsylvania. She graduated from Swarthmore College in 1920 and went on to Princeton to assist Henry Norris Russell. During this time she worked at the Princeton University Observatory and the Mt. Wilson Observatory. She worked extensively on solar spectroscopy, analyzing the spectral lines of the Sun and thereby identifying the chemical elements in the Sun. She earned a Ph.D. in astronomy in 1931 from the University of California, Berkeley on a Lick Fellowship, and then returned to Princeton.

During her second stay at Princeton, she met and married Bancroft W. Sitterly, who became a physics professor. She joined the then National Bureau of Standards (NBS) in 1945. Her tables of atomic spectra and energy levels, published by NBS, have remained essential references in spectroscopy for decades.

Later in her life, it became possible to launch instruments on rockets and she extended her work to the ultraviolet spectral lines.

Sitterly was given the Annie J. Cannon Award (1937), the William F. Meggers Award of the Optical Society of America (1972) and the Bruce Medal (1990).

The asteroid 2110 Moore-Sitterly is named in her honor.

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.

September 22: Pehr Wargentin

Pehr Wilhelm Wargentin

September 22, 1717 – December 13, 1783

Pehr Wargentin was a Swedish astronomer.

When Pehr Wargentin was 12 years old he observed a (total) lunar eclipse which would spark his life-long interest in Astronomy. During his tenure at Frösö trivialskola (elementary school), his teacher deemed him advanced enough to continue directly to Uppsala University. However, Wargentin's father wanted him first to attend the gymnasium (secondary school) of Härnösand, which he did. According to his own account, Wargentin was unimpressed with the purely classical and theological curriculum and the lack of any education in the sciences and did not finish the fourth year.

In 1735, Wargentin matriculated as a student at the University of Uppsala, where he excelled. Olof Hiorter was one of his instructors. He graduated in 1743 and became a docent in astronomy in 1746 and an adjunct in 1748. He was called to Stockholm as secretary of the Royal Swedish Academy of Sciences in 1749 on the death of secretary Pehr Elvius, Jr., and stayed on this post until his death. Wargentin therefore became the first long-serving secretary of the Academy, which had been founded in 1739. He is seen as an important person in leading the Academy to its first golden era. Wargentin also became the first director of the Stockholm Observatory founded by the Academy of Sciences on the initiative of his predecessor, Elvius, and completed in 1753.

Wargentin made studies on the moons of Jupiter and published his first paper on the topic in 1741 in the Acta of the Royal Society of Sciences in Uppsala.

The crater Wargentin on the Moon is named in his honor.

September 21: Arthur Covington

Arthur Edwin Covington

September 21, 1913 – March 17, 2001

Arthur Covington is a Canadian physicist who made the first radio astronomy measurements in Canada. Through these he made the valuable discovery that sunspots generate large amounts of microwaves at the 10.7 cm wavelength, offering a simple all-weather method to measure and predict sunspot activity, and their associated effects on communications. The sunspot detection program has run continuously to this day.

Covington was born in Regina and grew up in Vancouver. He showed an early interest in astronomy, and had built a 5-inch (130 mm) refractor telescope after meeting members of the local chapter of the Royal Astronomical Society of Canada. He was also interested in amateur radio and operated station VE3CC for a time. He started his career as a radio operator on ships operated by the Canadian National Railways. He put himself though school and eventually earned a bachelor's degree from the University of British Columbia in 1938, and obtained his master's degree from the same institution in 1940 after building an electron microscope. He then moved to University of California in Berkeley where he received his doctoral degree in nuclear physics in 1942. He was still at Berkeley when he was invited to join the National Research Council (NRC) in Ottawa in 1942 as a radar technician, working at the NRC's Radio Field Station.

Immediately after the war Covington became interested in radio astronomy, and built a small telescope out of the electronic parts from a surplus SCR-268 radar combined with parts from another receiver originally built to test silicon crystal radio parts for radar applications. These electronics were attached to the 4 ft (1.2 m) parabolic dish from a Type III gun-laying radar. The system operated at a frequency of 2800 MHz, or a wavelength of 10.7 cm. Initially the instrument was pointed in the direction of various celestial objects, including Jupiter, the Milky Way, aurora borealis, and the Sun, but it proved too insensitive to pick up any source other than the Sun. So a solar study program was started. As time passed, Covington and his colleagues realized that the Sun's emission at 10.7 cm wavelength was varying, which was unexpected. Thinking at that time was that the solar emission at centimeter wavelengths would be simply black body emission from a ball of hot gas.

Covington became convinced that the effect was due to sunspots, as the flux appeared to vary with the number of visible spots. The resolution of the device, about seven degrees, made it impossible to "pick out" a spot on the sun's surface for study, making a demonstration of the claim difficult. An opportunity to directly measure this possibility presented itself on November 23, 1946 when a partial solar eclipse passed over the Ottawa area, and Covington was able to conclusively demonstrate that the microwave emissions dropped off precipitously when the Moon covered a particularly large sunspot. This also demonstrated that magnetic fields were instrumental in sunspot activity.

Covington remained the director of the ARO until he retired in 1978. One of the buildings at the Dominion Astrophysical Observatory was named in his honour in 2003.

September 20: Gherman Titov

Gherman Stepanovich Titov

September 11, 1935 – September 20, 2000

Gherman Titov was a Soviet cosmonaut and the second man to orbit the Earth.

Titov went to school at the Stalingrad Military Aviation School. After graduating as an air force pilot, he was selected for cosmonaut training in 1960, and from there was chosen to fly the Vostok 2 mission launched in August 6, 1961. The mission lasted for 25.3 hours and accomplished 17 earth orbits. His call sign in this flight was Eagle. He landed close to the town of Krasny Kut in Saratov Oblast, Russia. A month short of 26 years old at launch, he remains the youngest person to fly in space.

His name refers to Saint Germanus and not to "a German".

In August 1961, he was the first person to suffer from "space sickness" (i.e. motion sickness in space) and was also the first human to sleep in space. He slept roughly for one orbit, and was surprised to awake with his arms floating in the air due to the absence of gravity. After securing his arms under a security belt, he went back to sleep, overslept and awoke 30 minutes later than predicted by the flight plan. He states (in the English version of his biography) that

"Once you have your arms and legs arranged properly, space sleep is fine ... I slept like a baby".

Following his space flight, Titov went on to assume various senior positions in the Soviet space programme until his retirement in 1992.

The crater Titov on the far side of the Moon is named in his honor.

September 19: Jean-Baptiste Delambre

Jean Baptiste Joseph, chevalier Delambre

September 19, 1749 - August 19, 1822

Jean-Baptiste Delambre was a French mathematician and astronomer. He was also director of the Paris Observatory, and author of well-known books on the history of astronomy from ancient times to the 18th century.

After a childhood fever, he suffered from very sensitive eyes, and believed that he would soon go blind. For fear of losing his ability to read, he devoured any book available to him and practised his ability to memorise. He thus immersed himself in Greek and Latin literature, acquired the ability to recall verbatim entire pages of books he may have read weeks beforehand, became fluent in Italian, English and German and even published Règles et méthodes faciles pour apprendre la langue anglaise (Easy rules and methods for learning English). In 1788, he was elected a foreign member of the Royal Swedish Academy of Sciences.

In 1801, First Consul Napoléon Bonaparte took the presidency of the Academy of Sciences and appointed Delambre its Permanent Secretary for the Mathematical Sciences, a post he held until his death.

After Méchain's death in 1804, he was appointed director of the Paris Observatory. He was also professor of Astronomy at the Collège de France. The same year he married Elisabeth-Aglaée Leblanc de Pommard, a widow with whom he had lived already for a long time. Her son, Achille-César-Charles de Pommard (1781-1807) assisted Delambre on several occasions in his astronomical and geodetical surveys, notably the measuring of the baselines for the meridian survey, and the latitude definition for Paris in December 1799 which was presented to the Conference of Savants.

Delambre was one of the first astronomers to derive astronomical equations from analytical formulas, was the author of Delambre's Analogies and, after the age of 70, also the author of works on the history of astronomy like the Histoire de l'astronomie.

He was a knight (chevalier) of the Order of Saint Michael and of the Légion d'honneur.

The crater Delambre on the Moon is named in his honor.

September 18: John Cobb Cooper, Jr.

John Cobb Cooper, Jr.

September 18, 1887 - July 22, 1967

John Cobb Cooper, Jr. was an American jurist, airline executive and presidential advisor.

From 1927–34 he was Editor-in-Chief of the Florida State Bar Association Law Journal. He was appointed to the International Technical Committee of Legal Aerial Experts, 1932–34. He became Vice President of Pan American Airways 1934–45, serving on the board of directors 1944–46. In 1947 he served as a consultant to the U.S. President's Air Policy Commission. He was a fellow at the Institute for Advanced Study in Princeton, 1945–50. In 1952 he was awarded his LL.D. from McGill University. From 1951–57 he was professor of International Air Law at McGill University, becoming the first director of the Institute of International Air Law, after which he was named Professor Emeritus.

He was the author of the book "The Right to Fly" and pioneered legal thought on air/space rights of man-made satellites in orbit, commencing with the launch of Sputnik in October 1957 when asked by President Eisenhower to render a legal opinion on "flyover rights" when Sputnik was orbiting over the United States. His honorary Doctorate from his alma mater, Princeton University, declared him the "Father of Air Space Law."

He was the legal counsel to the International Air Transport Association (IATA) from the early 1950s through the end of his life.

He was a pioneer in the field of international law as it applied to air and space. He wrote the first article on the topic of space ownership, "High Altitude Flight and National Sovereignty," in 1951.

His younger brother was movie producer Merian C. Cooper, perhaps most famous for the creation of the movie King Kong in 1933, and whose position as a Director of Pan Am was responsible for recommending his older brother for the position of Pan Am's legal consel and Vice President.

He flew with Charles Lindbergh, a consultant for PanAm, in small aircraft on site surveys to select sites in Ireland (Shannon) and France (Orly) for airports as Pan Am's services overseas increased.

The crater Cooper on the far side of the Moon is named in his honor.

September 17: Konstantin Tsiolkovsky

Konstantin Eduardovich Tsiolkovsky

September 17, 1857 – September 19, 1935

Konstantin Tsiolkovsky was an Imperial Russian and Soviet rocket scientist and pioneer of the astronautic theory. He is considered by many to be the father of theoretical astronautics. His works later inspired leading Soviet rocket engineers such as Sergey Korolyov and Valentin Glushko and contributed to the early success of the Soviet space program.

Tsiolkovsky theorized many aspects of space travel and rocket propulsion. He is considered the father of spaceflight and the first man to conceive the space elevator, becoming inspired in 1895 by the newly-constructed Eiffel Tower in Paris.

He was also an adherent of philosopher Nikolai Fyodorov, and believed that colonizing space would lead to the perfection of the human race, with immortality and a carefree existence.

In the late 19th and early 20th century, Tsiolkovsky delved into theories of heavier-than-air flying machines, independently working through many of the same calculations that the Wright brothers were doing at the same time. However, he never built any practical models, and his interest shifted to more ambitious topics. Because Tsiolkovsky's ideas were little known outside Imperial Russia, the field lagged until German and other scientists independently made the same calculations decades later.

In 1923, German physicist Hermann Oberth published his thesis By Rocket into Planetary Space, which triggered wide-scale interest and scientific research on the topic of space flight. It also reminded Friedrich Zander about once having read an article on the subject. After contacting the author, he became active in promoting and further developing Tsiolkovsky's work. In 1924 Zander established the first astronautics society in the Soviet Union, the Society for Studies of Interplanetary Travel, and later researched and built liquid-fuelled rockets named OR-1 (1930) and OR-2 (1933).

In 1924, a writer for the Russian newspaper Izvestiia reported on A Method of Reaching Extreme Altitudes, a groundbreaking work on the rocketry experiments being done by Robert Goddard, which had been published in 1919 but was not noticed in the Soviet Union until Hermann Oberth referenced it in his later work. When news of the article reached Tsiolkovsky, he decided to republish his early works along with a flurry of new articles about space.

His most important work, published in 1903, was The Exploration of Cosmic Space by Means of Reaction Devices, arguably the first academic treatise on rocketry. Tsiolkovsky calculated that the horizontal speed required for a minimal orbit around the Earth is 8,000 m/s (5 miles per second) and that this could be achieved by means of a multistage rocket fueled by liquid oxygen and liquid hydrogen.

During his lifetime he published over 500 works on space travel and related subjects, including science fiction novels. Among his works are designs for rockets with steering thrusters, multi-stage boosters, space stations, airlocks for exiting a spaceship into the vacuum of space, and closed cycle biological systems to provide food and oxygen for space colonies.

Tsiolkovsky's work influenced later rocketeers throughout Europe, like Wernher von Braun, and was also studied by the Americans in the 1950s and 1960s as they sought to understand the Soviet Union's successes in space flight.

The crater Tsiolkovskiy (the most prominent crater on the far side of the Moon) was named after him. The Soviet Union obtained naming rights by operating Luna 3, the first space device to successfully transmit images of the side of the moon not seen from Earth.

September 16: Francesco Maurolico

Francesco Maurolico

September 16, 1494 - July 21, 1575

Francesco Maurolico (in Latin, Franciscus Maurolycus) was an Italian mathematician and astronomer. Throughout his lifetime, he made contributions to the fields of geometry, optics, conics, mechanics, music, and astronomy.

Between 1548 and 1550, Maurolico stayed at the castle of Pollina in Sicily as a guest of the marquis Giovanni II Ventimiglia, and utilized the castle tower in order to carry out astronomical observations.

Maurolico's astronomical observations include a sighting of the supernova that appeared in Cassiopeia in 1572. Tycho Brahe published details of his observations in 1574; the supernova is now known as Tycho's Supernova.

In 1569, he was appointed professor at the University of Messina.

Maurolico's Photismi de lumine et umbra and Diaphana concern the refraction of light and attempted to explain the natural phenomenon of the rainbow. He also studied the camera obscura. His Arithmeticorum libri duo (1575) includes the first known proof by mathematical induction.

Maurolico published a Cosmographia in which he described a methodology for measuring the earth, which was later employed by Jean Picard in measuring the meridian in 1670.

Maurolico published an edition of Aristotle's Mechanics, and a work on music. He summarized Ortelius's Theatrum orbis terrarum and also wrote Grammatica rudimenta (1528) and De lineis horariis. He made a map of Sicily, which was published in 1575.

Maurolico worked on ancient mathematical texts: Theodosius of Bithynia, Menelaus of Alexandria, Autolycus of Pitane, Euclid, Apollonius of Perga and Archimedes. His didn't make new translations, but working on the existing ones, he provided new and sound interpretations of Greek mathematics.

The lunar crater Maurolycus is named after him.

September 15: Jean-Sylvain Bailly

Jean-Sylvain Bailly

September 15, 1736 – November 12, 1793

Jean-Sylvain Bailly was a French astronomer and orator, one of the leaders of the early part of the French Revolution. He was ultimately guillotined during the Reign of Terror.

Born in Paris, he was originally intended for the profession of a painter, but preferred writing tragedies, until attracted to science by the influence of Nicolas de Lacaille. He calculated an orbit for Halley's Comet when it appeared in 1759, reduced Lacaille's observations of 515 zodiacal stars, and was elected a member of the French Academy of Sciences in 1763. His Essai sur la theorie des satellites de Jupiter (Essay on the theory of the satellites of Jupiter, 1766), an expansion of a memoir presented to the Academy in 1763, showed much original power; and it was followed up in 1771 by a noteworthy dissertation Sur les inegalites de la lumiere des satellites de Jupiter (On the inequalities of light of the satellites of Jupiter). In 1778, he was elected a foreign member of the Royal Swedish Academy of Sciences.

Meantime, he had gained a high literary reputation by his Éloges of King Charles V of France, Lacaille, Molière, Pierre Corneille and Gottfried Leibniz, which were issued in collected form in 1770 and 1790; he was admitted to the Académie française on 26 February 1784, and to the Académie des Inscriptions in 1785, when Bernard le Bovier de Fontenelle's simultaneous membership of all three Academies was renewed in him.

From then on, he devoted himself to the history of science, publishing successively: Histoire de l'astronomie ancienne (A history of ancient astronomy, 1775); Histoire de l'astronomie moderne (A history of modern astronomy, 3 vols., 1779-1782); Lettres sur l'origine des sciences (Letters on the origin of the sciences, 1777); Lettres sur l' Atlantide de Platon (Letters on Plato's Atlantide , 1779); and Traite de l'astronomie indienne et orientale (A treatise on Indian and Oriental astronomy, 1787). The 1911 Encyclopædia Britannica remarks that "Their erudition was… marred by speculative extravagances."

The lunar crater Bailly is named in his honor.

September 14: Johann Kies

Johann Kies

September 14, 1713—July 29, 1781

Johann Kies was a German astronomer and mathematician. Born in Tübingen, Kies worked in Berlin in 1751 alongside Jérôme Lalande in order to make observations on the lunar parallax in concert with those of Nicolas Louis de Lacaille at the Cape of Good Hope.

From 1742 to 1754, at the recommendation of the mathematician Leonhard Euler, he was made professor of mathematics at Berlin's Academy of Sciences and astronomer at its observatory. His reports from this time include De la Situation la plus avantageuse des planètes pour découvrir les irrégularités de leurs mouvemens, Sur les Éclipses des étoiles fixes par la lune, and Description d'un instrument qui se trouve à l'observatoire de Berlin. In his Rapport de quelques observations célestes faites à l'observatoire Royal, Kies wrote, "

Observations on eclipses are extremely useful, especially the ones that are exact. They serve primarily to understand, if the theories on the Sun and the Moon are well or badly ascertained in the astronomical tables, and can either confirm them, or give us a need to reform them."

He subsequently taught also at the Collegium of Tübingen. From 1754 to 1755, Kies served as director of the Astronomisches Rechen-Institut in Heidelberg.

Kies was one of the first to propagate Newton's discoveries in Germany, and dedicated two of his works to the Englishman: De viribus centralibus (Tübingen, 1758) and De lege gravitatis (Tübingen, 1773). Kies is also the author of a work on lunar influences: De influxu lunae in partes terrae mobiles (Tübingen, 1769). He wrote many other works, both in French and in Latin, on astronomy.

Kies corresponded with Euler from 1747 to 1767. Their correspondence consists of 8 letters, all of which were written by Kies.

The crater Kies on the Moon is named in his honor.

September 13: Horace W. Babcock

Horace Welcome Babcock

September 13, 1912 – August 29, 2003

Horace Babcock was an American astronomer. He was the son of Harold D. Babcock.

He invented and built a number of astronomical instruments, and in 1953 was the first to propose the idea of adaptive optics. He specialized in spectroscopy and the study of magnetic fields of stars. He proposed the Babcock Model, a theory for the magnetism of sunspots.

During World War II, he was engaged in radiation work at MIT and Caltech. After the war he began a productive collaboration with his father.

Babcock was awarded the Henry Draper Medal (1957), the Eddington Medal (1958), the Bruce Medal (1969), the Gold Medal of the Royal Astronomical Society (1970) and the George Ellery Hale Prize of the American Astronomical Society Solar Physics Division (1992)

The asteroid 3167 Babcock is named jointly for Horace and his father. The Babcock crater on the Moon is named only for his father.

September 12: Guillaume Le Gentil

The ruins of Pondicherry in 1769 seen from the north. Le Gentil’s observatory was in the structure to the right of the flag pole.

Guillaume Joseph Hyacinthe Jean-Baptiste Le Gentil de la Galaisière

September 12, 1725 – October 22, 1792

Guillaume Le Gentil was a French astronomer.

He was born in Coutances and first intended to enter the church before turning to astronomy. He discovered what are now known as the Messier objects M32, M36 and M38, as well as the nebulosity in M8, and he was the first to catalogue the dark nebula sometimes known as Le Gentil 3 (in the constellation Cygnus).

He was part of the international collaborative project to measure the distance to the Sun, by observing the transit of Venus at different points on the earth. Edmond Halley had suggested the idea, but it required careful measurements from different places on earth, and the project was launched with more than a hundred observers dispatched to different parts of the globe, for observing the transit coming up in 1761. The French expedition turned out to be particularly unlucky, and perhaps the most unfortunate was Guillaume le Gentil, who set out for Pondicherry, a French colony in India.

He set out from Paris in March 1760, and reached Île de France (Mauritius) in July. But having learned that war had broken out between France and Britain, and deeming it dangerous to try and reach Pondicherry, he determined to go elsewhere; a frigate was bound for India's Coromandel Coast, and he sailed in March 1761. When they had nearly arrived they learned that the British had occupied Pondicherry, so the frigate was obliged to return to Île de France. June 6, the day of the transit, came, and the sky was clear, but he could not take astronomical observations with the vessel rolling about. After having come this far, he thought he might as well await the next transit of Venus, which would come in another eight years (they are relatively infrequent, occurring in pairs 8 years apart, but each such pair is separated from the previous and next pairs by more than a century.)

After spending some time mapping the eastern coast of Madagascar, he decided to record the 1769 transit from Manila in the Philippines. Encountering hostility from the Spanish authorities there, he headed back to Pondicherry, which had been restored to France by peace treaty in 1763, where he arrived in March 1768. He built a small observatory and waited patiently. At last, the day in question (June 4, 1769) arrived, but although the mornings in the preceding month had all been lovely, on this day the sky became overcast, and Le Gentil saw nothing. The misfortune drove him to the brink of insanity, but at last he recovered enough strength to return to France.

The return trip was first delayed by dysentery, and further when his ship was caught in a storm and dropped him off at Île Bourbon (Réunion), where he had to wait until a Spanish ship took him home. He finally arrived in Paris eleven years later in October 1771, only to find that he had been declared legally dead and been replaced in the Royal Academy of Sciences. His wife had remarried, and all his relatives had "enthusiastically plundered his estate". Lengthy litigation and the intervention of the king were ultimately required before things were normalized. He got back his seat in the academy, remarried, and lived apparently happily for another 21 years.

One of his interesting findings was that the duration of the lunar eclipse of 30 August 1765 was predicted by a Tamil astronomer, based on the computation of the size and extent of the earth-shadow (going back to Aryabhata, 5th c.), and was found short by 41 seconds, whereas the charts of Tobias Mayer were long by 68 seconds.

The Lunar crater Le Gentil is named in his honor.