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  • Elizabeth Cocking

In this month: July 2021

29th July 1851

The asteroid Eunomia is discovered by Italian astronomer Annibale de Gasparis. It is the 12th largest object in the main asteroid belt and also the largest member of the Eunomia asteroids (a large family of S-type asteroids). It has a diameter of 357 kilometres with a composition of silicates and nickel-iron and is light in colour. NASA does not consider Eunomia as potentially hazardous because its orbit does not bring it close to Earth.

The asteroid was named after Eunomia a minor goddess of law and legislation in Greek mythology.

11th July 1979

Skylab makes a spectacular return to earth, breaking up in the atmosphere and showering burning debris over the Indian Ocean and Australia. Launched in 1973, Skylab was the world’s first successful space station safely housing three separate three-man crews for extended periods of time. Five years after the last Skylab mission, the space station’s orbit began to deteriorate earlier than anticipated because of unexpectedly high sunspot activity. NASA engineers decommissioned the spacecraft sending it into a slow tumble to avoid it re-entering a populated area.

Image left courtesy NASA

22nd July 2009

The longest total solar eclipse of the 21st century occurs lasting 6 minutes and 39 seconds creating an amazing spectacle for observers. The 258 kilometre wide path of totality passed through India, Nepal, Bangladesh, Bhutan, Myanmar and China crossing over Japan's Ryukyu Islands before curving southeast through the Pacific Ocean. The next time a longer total solar eclipse occurs will be on Friday 13th June 2132 with a totality of 6 minutes 55 seconds. ON the left is an animation by NASA.

However, this will be surpassed on the 16th July 2186 with the longest total solar eclipse for the third millennium, and indeed for thousands of years, when totality lasts for 7 minutes 29 seconds.


16th July 1746 Giuseppe Piazzi. Italian Catholic priest, astronomer and mathematician. He was famous for discovering the first dwarf planet, Ceres on the 1st January 1801. Following on from the success of discovering Ceres he studied the proper motions of stars, one of them, 61 Cygni, is still sometimes referred to as Piazzi's Flying Star. In 1923 the 1,000th asteroid to be numbered was named 1000 Piazzia in his honour. The lunar crater Piazzi was named after him in 1935.

30th July 1746 Louise du Pierry or Dupiery, French astronomer and professor. In 1789, she became the first female professor of astronomy at the Sorbonne university in Paris supervising the first astronomy course for women. The course was a huge success despite many fearing the subject matter would be too difficult for women. During her career she predicted eclipses by collecting historical data over the past century, computed tables for the length of day and night and assembled refraction tables in right ascension and declination for the latitude of Paris.

In 1790 French astronomer Jerome De Lalande dedicated his work, Astronomie des Dames, (Ladies’ Astronomy), to her where she is praised for her talent, taste, and courage in the field of science.


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