Editing Joseph von Fraunhofer (section)

=== Invention of optical instruments ===
Fraunhofer also developed a [[diffraction grating]] in 1821, after [[James Gregory (astronomer and mathematician)|James Gregory]] discovered the phenomenon of diffraction grating and after the American astronomer [[David Rittenhouse]] invented the first manmade diffraction grating in 1785.<ref>See:
* Frauhofer. Jos. (1821) [https://books.google.com/books?id=k-EAAAAAYAAJ&pg=RA1-PA3 "Neue Modifikation des Lichtes durch gegenseitige Einwirkung und Beugung der Strahlen, und Gesetze derselben"] (New modification of light by the mutual influence and the diffraction of [light] rays, and the laws thereof), ''Denkschriften der Königlichen Akademie der Wissenschaften zu München'' (Memoirs of the Royal Academy of Science in Munich), '''8''': 3–76.
* Fraunhofer, Jos. (1823) [http://gallica.bnf.fr/ark:/12148/bpt6k15083w/f353.image "Kurzer Bericht von den Resultaten neuerer Versuche über die Gesetze des Lichtes, und die Theorie derselben"] {{Webarchive|url=https://web.archive.org/web/20160216172921/http://gallica.bnf.fr/ark:/12148/bpt6k15083w/f353.image |date=16 February 2016 }} (Short account of the results of new experiments on the laws of light, and the theory thereof) ''Annalen der Physik'', '''74'''(8): 337–378.</ref><ref>{{cite journal |author=Parker AR |title=A geological history of reflecting optics |journal=Journal of the Royal Society, Interface |volume=2 |issue=2 |pages=1–17 |date=March 2005 |pmid=16849159 |pmc=1578258 |doi=10.1098/rsif.2004.0026}}</ref> Fraunhofer was the first who used a diffraction grating to obtain line spectra and the first who measured the wavelengths of spectral lines with a diffraction grating.

Ultimately, however, his primary passion was still practical optics; he once wrote that "In all my experiments I could, owing to lack of time, pay attention to only those matters which appeared to have a bearing upon practical optics".<ref>Prismatic and Diffraction Spectra: Memoirs (1899) Tr. & Ed. J. S. Ames p. 10</ref>