Alvan Graham Clark was born in Fall River, Massachusetts. He was a very important astronomer that has greatly influenced the study of astronomy today. Clark was the son of another great astronomer, Alvan Clark. His father had a company which used to be the largest one that grounded lenses for refracting telescopes.
The main reason that Alvan Graham Clark is known is because of his discovery of Sirius B, a companion of Sirius and the first known white dwarf. A white dwarf being a star, approximately the size of the earth, that has undergone gravitational collapse and is in the final stage of evolution for low-mass stars. It is a small, extremely dense star characterized by high temperature and luminosity. A white dwarf is believed to be in its final stage of evolution, having either used up most of its nuclear fuel in its main-sequence stage, or else moved through a giant stage and shed any remaining fuel in its outer layer as a planetary nebula, leaving only a glowing core. Some 10 percent of all stars in the Milky Way are white dwarfs, but despite their intrinsic luminosity, they are so small that none are visible to the naked eye. Clark was testing out the Dearborn telescope which had an 18 inch lens.
When Clark was old enough, he became a partner in business with his father at his father's lens company along with his older brother. The Yerkes observatory telescope was designed by Clark, his father and his brother. I think it is pretty cool that he got to work with his family and they made some of the best lenses ever. They are all very well known when it comes to telescopes but Alvan Graham Clark's main thing he is known for is the discovery of Sirius B as I said beforehand.
With Clark's discovery. he was awarded the Lalande prize. The Lalande prize is given to the person who demonstrates chief astronomical performance every year. Being the first person to discover a white dwarf really gained Clark tons of regonition.
