John Crosley facts for kids
John Crosley (born 1762, died 1817) was an English astronomer and mathematician. He worked as an assistant at the Royal Observatory, Greenwich. He also helped create the Nautical Almanac, a very important book for sailors. John Crosley went on exciting sea voyages to explore and observe the stars. He was also a leader in the Spitalfields Mathematical Society.
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John Crosley's Life and Work
John Crosley was born in Yorkshire, England. We don't know much about his early life. He started working at the Royal Observatory, Greenwich in 1789. This observatory was a very important place for studying stars and time. He helped the main astronomer, Nevil Maskelyne.
Adventures at Sea
From 1793 to 1798, John Crosley joined a big expedition. He was an observer for the Board of Longitude. This group helped sailors find their exact location at sea. Crosley sailed with George Vancouver to the north-west coast of America. He replaced another astronomer, William Gooch.
During this trip, Crosley's ship, the HMS Providence, was wrecked. It hit a reef near Okinawa. He had to return to England on a different ship. He lost his books and tools in the shipwreck. The Board of Longitude later gave him £400 to help with his losses. He was very careful with his observations. He wrote down everything he saw and any problems he faced. This included details about the shipwreck.
Return to Greenwich and New Voyages
Crosley worked at the Royal Observatory again in 1798. He then joined another important voyage. He was an observer for Matthew Flinders's trip around Australia. This journey started in 1801. However, John Crosley became ill. He had to return home in 1802 from the Cape of Good Hope.
On this voyage, he made many observations. He especially focused on finding the ship's exact position. He used two main methods. One was the lunar-distance method. This involved measuring the distance between the Moon and other stars. The other method used very accurate timekeepers.
Work as a Computer and Society President
Besides working at the Royal Observatory, John Crosley had another important job. He was a "computer" for the Nautical Almanac. This meant he did many calculations for the book. This job provided him with a good income from 1799 until he passed away.
He was also a member of the Spitalfields Mathematical Society for 31 years. This was a group of people who loved math and science. He became the president of this society around 1800. He remained president until his death in 1817. An old picture of him from 1813 says he had been president for 13 years.
