<?xml version="1.0" encoding="UTF-8"?>
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  <Identification_Area>
    <logical_identifier>urn:nasa:pds:context:instrument:dushanbe.rcc.sanglok</logical_identifier>
    <version_id>1.0</version_id>
    <title>Sanglok Observatory Photometer-Polarimeter</title>
    <information_model_version>1.10.0.0</information_model_version>
    <product_class>Product_Context</product_class>
    <Modification_History>
      <Modification_Detail>
        <modification_date>2020-02-18</modification_date>
        <version_id>1.0</version_id>
        <description>Initial export from OLAF</description>
      </Modification_Detail>
    </Modification_History>
  </Identification_Area>
  <Reference_List>
    <Internal_Reference>
      <lid_reference>urn:nasa:pds:context:telescope:dushanbe.rcc</lid_reference>
      <reference_type>instrument_to_telescope</reference_type>
    </Internal_Reference>
    <External_Reference>
      <reference_text>Kayumov V.V., N.N. Kiselev, P.A. Pushnin, V.Yu. Rakhimov, V.I. Siklitskij, K.V.
Tarasov, G.P. Chernova, and V.N. Yakutovich, The investigation of the
photometer-polarimeter of the 1-m RCC telescope. Bull. Inst. Astrophyz. Tadjik Acad.
Sci. No. 78, p. 10-16 (in Russian), 1989.</reference_text>
    </External_Reference>
  </Reference_List>
  <Instrument>
    <name>Sanglok Observatory Photometer-Polarimeter</name>
    <type>Polarimeter</type>
    <description>The single-channel photometer-polarimeter at Sanglok Observatory was built at the
Institute of Astrophysics of Tadjik Academy of Sciences. It allowed
quasi-simultaneous photometric and polarimetric observations. The useble wavelength
range was 0.35-0.75 microns. The polarimeter worked on the modulation principle with
a rapidly-rotating polarizer as the analyzer. The rotation frequency of the polarizer
was about 33 revolutions per second. Four impulse counters were used to registrate
impulses during each quarter of a polarizer revolution. The total number of impulses
in four positions of the polarizer allow the derivation of the values of the Stokes Q
and U parameters and hence the value of the degree of linear polarization and the
position angle. The observing procedure included consecutive measurements of an
object and a sky background near the object with the same diaphragm.  To control the
stability of instrument operation the measurements of a built-in signal generator
were used.

For more information, see

Kayumov V.V., Kiselev N.N., Pushnin P.A., Rakhimov V.Yu., Siklitskij V.I., Tarasov
K.V., Chernova G.P., Yakutovich V.N. The investigation of the photometer-polarimeter
of the 1-m RCC telescope. Bull. Inst. Astrophyz. Tadjik Acad. Sci No. 78, p. 10-16,
1989 (in Russian).</description>
  </Instrument>
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