Nephoscope

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Nephoscope
Mirror with compass rose
(description in text)

Nephoscope ( Greek nephele, nephos ; fog, cloud), also known as cloud mirror or cloud meter , is an instrument for measuring the direction and apparent speed of cloud movements .

description

The cloud mirror consists of an ordinary mirror and a black mirror placed on the back with an incised compass rose . Usually the black mirror is used, the bright one only for very weakly lit clouds. Before each observation , the mirror is placed horizontally so that "N" is pointing north .

The observer positions himself so that he sees a characteristic point of the cloud in the small central circle and observes which side the cloud image is moving towards. The opposite direction to this indicates the direction from which the clouds are coming. After that determines the time in which the selected position of the clouds in the mirror a known distance travels, z. B. the 2 cm long way from one circle to the next. The angular velocity sought is then equal to the length of the path that the mirror image has made, divided by the product of the number of seconds it took for this path and the perpendicular distance of the eye from the mirror.

history

The cloud mirror was invented by Aimé in 1845. The name Nephoscope goes back to the physics teacher Carl Braun , who constructed a similar instrument in 1865.

literature

  • Josef Reiner: The meteorological instruments. Rudolf A. Lang Verlag, Pößneck 1949 ( portal.dnb.de ).

See also

Individual evidence

  1. ^ Meyers Konversations-Lexikon 1896: Nephoskop (eLexikon)
  2. ^ Eduard Raskop: The master optician. Thüringer Volksverlag GmbH, Erfurt 1951, p. 322.
  3. ↑ Cloud mirror . In: Meyers Großes Konversations-Lexikon . 6th edition. Volume 20, Bibliographisches Institut, Leipzig / Vienna 1909, p.  736 .
  4. ^ Otto Lueger : Lexicon of the entire technology and its auxiliary sciences. Volume 6, Deutsche Verlagsanstalt, Stuttgart and Leipzig 1904, p. 605 ( zeno.org ).
  5. ↑ Carl Braun: The Nephoscope. Instrument for determining the direction and speed of the wind in higher regions. Wigand, Leipzig 1865 ( mdz-nbn-resolving.de ).