Anders Celsius was born in Uppsala, Sweden on November 27, 1701. Celsius was a Swedish astronomer, physicist, mathematician, poet, and writer of popular science. He was born into a well-known scientific family. His father, Nils Celsius, was a professor in astronomy. His two grandfathers; Magnus Celsius was a mathematician and Anders Spole was an astronomer. Celsius, was said to be talented in mathematics from an early age, and even succeeded his father as professor of astronomy in 1730. When Celsius was first appointed professor there was no observatory in Sweden. Celsius began a round trip to some of the European astronomy sites in 1732. He went from Nuremberg and Rome to Paris in 1734.
Celsius became caught up in the middle of the dispute between the English and French astronomer about the shape of the Earth. To help find answers, Celsius joined Pierre Louis de Maupertius as an assistant for the expeditions to the north. They journeyed to Lapland, the northern most part of Sweden and it lasted from 1736 to 1737. Between the journey and other measurements they confirmed the theory of Newton with the flattening of the Earth's poles.
When Celsius returned to Uppsala he worked on the construction of the first observatory in Sweden, which was finished in 1740. In 1740, Celsius became director of the observatory. He published descriptions of the northern lights, or aurora borealis in 1733. After traveling to Lapland, Celsius began to examine the changes of the Earth's magnetic field at the time of the Northern light. Celsius was the first to measure the brightness of stars with photometric devices. .
In 1742, Celsius became famous for the recommendation to divide the temperature scale of a mercury thermometer at 760mm mercury air pressure into 100 degrees. Celsius originally set the scale to the freezing point of water at 100°C and the boiling point of water at 0°C. After findings and measurements by Gabriel Daniel Fahrenheit and Antoine Ferchault de Reaumur, Celsius revised the scale to the freezing point of water at 0°C and the boiling point of water at 100°C.
