SANGLOK OBSERVATORY                     
        PHOTOMETER-POLARIMETER
==============================

  Instrument Overview                                                         
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    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).

References
==========

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.