Template:Selected anniversaries/April 6: Difference between revisions

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File:Pieter Rijke.jpg|link=Pieter Rijke (nonfiction)|1889: Physicist and crime-fighter [[Pieter Rijke (nonfiction)|Petrus Leonardus Rijke]] invents the Rijke tube, which neutralizes [[Crimes against physical constants|crimes against audio constants]] by creating a self-quantumizing standing wave.
File:Pieter Rijke.jpg|link=Pieter Rijke (nonfiction)|1889: Physicist and crime-fighter [[Pieter Rijke (nonfiction)|Petrus Leonardus Rijke]] invents the Rijke tube, which neutralizes [[Crimes against physical constants|crimes against audio constants]] by creating a self-quantumizing standing wave.
||1890: André-Louis Danjon born ... astronomer who devised a now standard five-point scale for rating the darkness and colour of a total lunar eclipse, which is known as the Danjon Luminosity Scale. He studied Earth's rotation, and developed astronomical instruments, including a photometer to measure Earthshine - the brightness of a dark moon due to light reflected from Earth. It consisted of a telescope in which a prism split the Moon's image into two identical side-by-side images. By adjusting a diaphragm to dim one of the images until the sunlit portion had the same apparent brightness as the earthlit portion on the unadjusted image, he could quantify the diaphragm adjustment, and thus had a real measurement for the brightness of Earthshine.*TIS  Pic search yes: https://www.google.com/search?q=André-Louis+Danjon


||1890: Anthony Fokker born ... engineer and businessman, founded Fokker Aircraft Manufacturer. Pic.
||1890: Anthony Fokker born ... engineer and businessman, founded Fokker Aircraft Manufacturer. Pic.

Revision as of 14:23, 7 April 2019