Julius Scheiner was a German astronomer

Astronomy

Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, born in Cologne

Cologne

Cologne is Germany's fourth-largest city , and is the largest city both in the Germany Federal State of North Rhine-Westphalia and within the Rhine-Ruhr Metropolitan Area, one of the major European metropolitan areas with more than ten million inhabitants.Cologne is located on both sides of the...

 and educated at Bonn

Bonn

Bonn is the 19th largest city in Germany. Located in the Cologne/Bonn Region, about 25 kilometres south of Cologne on the river Rhine in the State of North Rhine-Westphalia, it was the capital of West Germany from 1949 to 1990 and the official seat of government of united Germany from 1990 to 1999....

. He became assistant at the astrophysical observatory in Potsdam

Potsdam

Potsdam is the capital city of the German federal state of Brandenburg and part of the Berlin/Brandenburg Metropolitan Region. It is situated on the River Havel, southwest of Berlin city centre....

 in 1887 and its observer in chief in 1898, three years after his appointment to the chair

Chair (official)

The chairman is the highest officer of an organized group such as a board, committee, or deliberative assembly. The person holding the office is typically elected or appointed by the members of the group. The chairman presides over meetings of the assembled group and conducts its business in an...

 of astrophysics

Astrophysics

Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

 in the University of Berlin

Humboldt University of Berlin

The Humboldt University of Berlin is Berlin's oldest university, founded in 1810 as the University of Berlin by the liberal Prussian educational reformer and linguist Wilhelm von Humboldt, whose university model has strongly influenced other European and Western universities...

. Scheiner paid special attention to celestial photography and wrote Die Spektralanalyse der Gestirne (1890); Lehrbuch der Photographie der Gestirne (1897); Strahlung und Temperatur der Sonne (1899); Der Bau des Weltalls (1901); third edition, 1909). In 1899 he began the publication of the Photographische Himmelskarte; Zone +31° bis +40° Deklination.

He is also credited with developing the first system for measuring the sensitivity of photographic emulsions in 1894, Scheinergrade, which also inspired the later DIN 4512 standard to measure film speed

Film speed

Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system....

s.