Astro Anniversaries

April

Day	Year	Event
1 Apr	1960	Tiros 1 (Television and InfraRed Observation Satellite) launched – the first weather observation satellite and the first to take a television image of the Earth from space.
1 Apr	2010	Henry Hatfield died. An amateur astronomer and much respected member of the BAA. Well-known for his Photographic Lunar Atlas which was first published in 1968.
2 Apr	1845	Hippolyte Fizeau and Leon Foucault in France took the first photograph of the Sun in 1845, using the daguerreotype process.
2 Apr	1958	President Eisenhower proposed the establishment of NASA in a special message to the US Congress.
3 Apr	2014	NASA announced that the Cassini orbiter had found evidence of an underground body of water on Enceladus, a moon of Saturn.
4 Apr	1914	Zdeněk Kopal born. He was a Czechoslovak astronomer who mainly worked in England. Kopal studied variable stars and, in particular, close eclipsing binary stars. He became head of the astronomy department at the University of Manchester and later assisted NASA with the Apollo program as an external expert. He was editor-in-chief of the journal Astrophysics and Space Science from its foundation in 1968 until his death in 1993. The asteroid 2628 Kopal was named in his honour.
6 Apr	1893	A rare Hybrid Solar Eclipse took place – this is when an annular and a total eclipse take place together, where the former becomes the latter and then usually reverts back. There will be only seven such eclipses in the 21st century.
7 Apr	2001	The Mars Odyssey orbiter was launched to map and search for water on Mars.
8 Apr	1960	Frank Drake began observations for Project Ozma in 1960 at the National Radio Astronomy Observatory, the first serious search for radio signals from extra-terrestrial civilizations.
8 Apr	2016	Elizabeth “Pat” Roemer died. An American astronomer and educator, Pat Roemer specialized in astronomy, with a particular focus on comets and minor planets. She was well-known for the recovery of lost comets, as well as for her discovery of two asteroids, the co-discovery of Jupiter’s moon Themisto, and for the asteroid 1657 Roemera that was named in her honour.
9 Apr	1907	Percival Lowell discovered Minor Planet 793, which he named ‘Arizona’ after the state where his Lowell Observatory is located.
10 Apr	1997	Martin Schwarzschild died. He was a German-American astrophysicist who worked mainly in the fields of stellar structure and evolution. In his later years, he made significant contributions toward understanding the dynamics of elliptical galaxies. Schwarzschild was the Eugene Higgins Professor Emeritus of Astronomy at Princeton University, where he spent most of his professional life.
10 Apr	2002	Yuji Hyakutake died. He was a Japanese amateur astronomer who discovered the splendid Comet C/1996 B2, also known as Comet Hyakutake on January 31, 1996, while using 25×150 binoculars to look for C/1995 Y1, a comet he had discovered a few weeks before.
11 Apr	1879	Bernhard Schmidt born. In 1930 he invented the Schmidt telescope which corrected for the optical errors of spherical aberration, coma, and astigmatism, making possible the construction of very large, wide-angled cameras with short exposure time for astronomical research.
12 Apr	1817	Charles Messier died. A French astronomer who published a catalogue of 110 galaxies, nebulae and star clusters to prevent astronomers mistaking these objects for comets. The objects were numbered and catalogued with the prefix ‘M’, and came to be known as the Messier objects (eg M31 is the Andromeda galaxy).
12 Apr	1961	Cosmonaut Yuri Gagarin became the first human to enter outer space when he was launched into orbital flight in Vostok 1.
12 Apr	2010	Douglas Walter Noble Stibbs died. Prof Stibbs was an Australian astronomer and astrophysicist, remembered for his work at St Andrews University where he held the Napier Chair in Astronomy for 30 years.
14 Apr	1629	Christiaan Huygens born. He was pioneering physicist and astronomer, born in the Hague in the Netherlands. Huygens went on to discover Saturn’s largest moon and characterise its ring system, invent the pendulum clock and suggest the equation for centripetal force, amongst many other contributions to science.
14 Apr	1792	Maximilian Hell died. He was a Viennese Jesuit court astronomer. Hell was a nodal figure in the eighteenth-century circulation of knowledge. He was already famous by the time of his celebrated 1769 expedition for the observation of the transit of Venus in northern Scandinavia. The crater Hell on the Moon is named after him.
15 Apr	1452	Leonardo Da Vinci born. He discussed the ‘ashen glow’ of the Moon, the phenomenon appearing as a ghostly glow of the Moon’s full orb which today we call ‘earthshine’.
17 Apr	1971	The first space station, Salyut 1, was launched into orbit by Russia.
18 Apr	1949	Will Hay died. A famous comedian and actor, he is noted for having discovered a Great White Spot on the planet Saturn in 1933. Hay kept his career in astronomy separate from his comedy career and published Through My Telescope under the name of W.T. Hay. He was an advocate for education on astronomy and gave public lectures on the subject.
18 Apr	1955	Albert Einstein died. German-American physicist, engineer and academic. Nobel Prize laureate.
19 Apr	1982	The Salyut 7 space station was launched.
20 Apr	1786	John Goodricke died. He was an English astronomer who was the first to notice that some variable stars were periodic in nature. In particular, he suggested that the variability of Algol (β Persei, also known as the Demon Star) was due to its being periodically eclipsed by a darker companion body. Goodricke reported his findings to the Royal Society who awarded him a Copley Medal in 1783. Sadly, Goodricke fell ill and died at the young age of 21.
24 Apr	1906	Richard van der Riet Woolley born. An English astronomer who became the 11th Astronomer Royal (1956 -1971). Woolley specialized in solar astronomy and in 1939 he was appointed director of the Commonwealth Solar Observatory in Canberra, Australia.
24 Apr	1957	The first edition of BBC television’s The Sky at Night programme was broadcast. It was introduced by Paul Johnstone, but featured Patrick Moore who presented the programme until his death in December 2012, making him the longest-running host of the same TV programme ever.
24 Apr	1990	The Hubble Space Telescope was launched into orbit around the Earth.
25 Apr	1918	Gérard de Vaucouleurs born. He was a French astronomer known for his work in extragalactic astronomy. He developed a classification system for galaxies based on their morphology. He served as the director of the University of Texas McDonald Observatory.
26 Apr	1920	The Shapley-Curtis debate on the nature of the ‘spiral nebulae’ was held in 1920 at the Smithsonian Institution’s Museum of Natural History in Washington, DC. It showed the division among astronomers about whether or not our Milky Way galaxy constituted the entirety of the universe.
27 Apr	1933	Karl Jansky made the first public announcement (at a meeting of the International Scientific Radio Union in Washington, DC) of his discovery of radio waves from the centre of our galaxy – thus began the field of Radio Astronomy.
28 Apr	1900	Jan Oort born. Oort established the existence of the distant region of comets now called the Oort Cloud.
28 Apr	1926	Vincent Reddish born. He was a British astronomer who spent much of his career in Edinburgh, where he made significant contributions to British optical astronomy. He was the 8th Astronomer Royal for Scotland, the Director of the Royal Observatory, Edinburgh and Regius Professor at the University of Edinburgh (all from 1975–80).
28 Apr	1928	Eugene Shoemaker born. Shoemaker was an American geologist and planetary scientist who made significant contributions to the study of impact craters and the formation of the Solar System. He co-discovered Comet Shoemaker-Levy 9 which collided with Jupiter in July 1994.
29 Apr	2001	Aerospace engineer and financial analyst Dennis Tito became the first space tourist at the age of 60. He paid $20 million to fly aboard a Russian Soyuz spacecraft and spend a week on the International Space Station (ISS).
30 Apr	1967	The first image of the Earth was taken from the Moon’s surface by the Surveyor 3 lander.

LAST UPDATED: 2025-04-03