๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

On polarimetry in solar active regions

โœ Scribed by E. Wiehr; M. Rossbach

Book ID
104644269
Publisher
Springer
Year
1974
Tongue
English
Weight
357 KB
Volume
35
Category
Article
ISSN
0038-0938

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โœฆ Synopsis

Phase retardation caused by the Gr6gory-Coud6 telescope at Locarno is determined empirically and compared with calculations. Good agreement is found for a proper retardation angle A = 16 ~ for each of the two plane mirrors in the telescope.

The praxis of compensation by means of two 2/8-plates (Bowen compensator) is described and tested. It is found that the phase retardation r can be compensated down to the limits of detectability (T< 1%

It is known that the same quality of compensation can easily be achieved on the telescopic linear polarization by means of a tilted glass plate. Hence, among telescopes fitting to fixed spectrographs, those are most suited for solar Zeeman polarimetry where the beam passes along the a-and 5-axes, since telescopic effects depend only on 5 and can for the entire day rather simply be compensated.

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