In this month: July
4 July 1054
Chinese astronomers notice a star explode becoming a supernova in the constellation Taurus. It remained visible in the night sky for 653 days. The remnant of that exploding star is what we now know as the Crab Nebula. The supernova shone roughly four times brighter than Venus and for a while was the third-brightest object in the sky, after the Sun and Moon. Image: The Crab Nebula in Taurus, Credit: ESO.
The Chinese weren't the only ones to make a sighting. Astronomers in the Arab world provided their own accounts and archaeological evidence suggests that North American Indian sky watchers also recorded the supernova.
The object was “rediscovered” again by Charles Messier in 1758, and became the first object in his catalogue, now known as the Messier Catalogue. Thus, the Crab Nebula is often referred to as M1.
28 July 1851
A total solar eclipse occurs and the earliest scientifically useful photograph of a total solar eclipse was made by Julius Berkowski at the Royal Observatory in Königsberg, Prussia. It was the first correctly exposed photographic image taken during totality and included the Sun's corona. Photographing a rare event such as a total eclipse posed unique challenges for early photography. Prior to this eclipse no properly exposed photograph of the solar corona had been produced. The observers attached a small six-centimetre refracting telescope to a 15.8 centimetre Fraunhofer heliometer, and Berkowski made an eighty-four second exposure shortly after the beginning of totality.
25 July 1984
Russian cosmonaut Svetlana Savitskaya becomes the first woman to do a spacewalk, lasting 3 hours and 35 minutes outside the Salyut 7 space station during which time she cut and welded metals in space along with her colleague Vladimir Dzhanibekov. In total, across all space agencies, only 15 women have completed spacewalks. Of the 67 Russian/Soviet spacewalkers she is the only woman. She is also the first woman to fly into space twice. Image Credit: wikicommons.
BORN IN JULY
9 July 1845
Sir George Howard Darwin. English astronomer and barrister, and the second son and fifth child of naturalist Charles Darwin. He proposed the theory that the Moon was once part of the Earth, until it was pulled free to form a satellite, and was the first to develop a theory of evolution for the Sun–Earth–Moon system based on mathematical analysis in geophysical theory.
Darwin was a Fellow of the Royal Astronomical Society (RAS) and served as its President from 1899–1901. in 1984 The RAS founded a prize lectureship and named it the George Darwin Lectureship in his honour.
5 July 1888
Louise Freeland Jenkins American astronomer. She compiled a valuable catalogue of stars within 10 parsecs of the Sun, as well as editing the 3rd edition of the Yale Bright Star Catalogue.
She was noted for her research into the trigonometric parallax of nearby stars and also studied variable stars.
The crater Jenkins on the Moon is named after her.
7 July 1950
Yuji Hyakutake Japanese amateur astronomer. Comet hunter. Using 25×150 binoculars he discovered Comet C/1996 B2, also known as Comet Hyakutake, one of the most spectacular comets of modern times, almost by accident while looking for a comet he had discovered the previous month. It remained visible to the naked eye for three months and was the brightest comet seen in 20 years. The tail was perhaps its most spectacular feature, stretching out more than 100 degrees as seen from Earth. Image of comet C/1996 B2 (Hyakutake), taken on 25 March 25 1996, Credit: E. Kolmhofer, H. Raab; Johannes-Kepler-Observatory, Linz, Austria.
Hyakutake died in 2002 at the relatively young age of 51. The Asteroid 7291 Hyakutake is named after him