What is Hermann Carl Vogel?
{{distinguish|Hermann Wilhelm Vogel}} {{Infobox Scientist |name = Hermann Carl Vogel |image =Vogel Hermann Carl.jpg |image_size =350px |caption = Hermann Carl Vogel |birth_date = {{birth date|1841|4|3|df=y}} |birth_place = [[Leipzig]], [[Kingdom of Saxony]] |death_date = {{death date and age|1907|8|13|1841|4|3|df=y}} |death_place = [[Potsdam]], [[German Empire]] |residence = |citizenship = |nationality = [[Germany|German]] |field = [[Astronomy]] |work_institutions = [[Potsdam Observatory]] |alma_mater = |doctoral_advisor = |doctoral_students = |known_for = [[spectroscopy|Astronomical spectroscopy]] |author_abbrev_bot = |author_abbrev_zoo = |influences = |influenced = |prizes = |footnotes = |signature = }} '''Hermann Carl Vogel''' (born 3 April 1841, died 13 August 1907) was a [[Germany|German]] [[astronomer]]. He was born in [[Leipzig]], [[Kingdom of Saxony]]. Vogel was one of the first astronomers to use a [[spectroscope]] in astronomy. He used it to read the [[chemicals]] on planets far away and to measure the time it takes the [[Sun]] to spin. He could read it by measuring the [[Doppler effect]]. In 1882, Vogel became the Director at the [[Astrophysical Institute Potsdam|Astrophysical Observatory Potsdam]] and he is best known for some work there in 1890. Vogel found that the colour of some stars changed over time, becoming red and then later becoming blue. His idea was that the star was moving toward and then away from the Earth, and that the colour changes were the because of that movement. These stars seemed to be [[orbit]]ing around a hidden star as if they were double-stars but the second star could never be seen, only known by the colour changing Doppler effect. Volgel proved that [[Algol]] was a double star that could not be seen (spectroscopic binary star) and it was one of the first of these double stars proven to exist. ==Medals