urn:nasa:pds:context:instrument:kpno.boller1m3.kpsc 1.0 1.10.0.0 Product_Context 2020-02-18 1.0 Initial export from OLAF urn:nasa:pds:context:telescope:kpno.boller1m3 instrument_to_telescope Dyck, H.M and M.T. Sandford II, Multicolor polarimetry of some Mira variables, Astronomical Journal 76, 43-49, 1971. Shakhovskoy, N.M. and N.A. Dymov, Publ. Crimean Astrophys. Obs. 27, 291, 1962. KPNO Single Channel Polarimeter Polarimeter The Single-channel Polarimeter was put into service for the Kitt Peak 36- and 50-inch telescopes in August 1969. It is similar to one built at the Crimean Astrophysical Observatory (Shakhovskoy and Dymov 1962). The main element of the device is a rapidly rotating polarizer mounted in a circular disk containing 100 radial slots spaced uniformly around the perimeter. The disk serves to encode the angular position of the polarizer. A star-chopping technique is used to compensate for sky brightness by means of a pair of closely matched diaphragms in the focal plane. The remainder of the polarimeter includes a moveable filter slide immediately following the polarizer, and then a Lyot depolarizer. The final optical element is a CuSO4-5H2O crystal in a moveable slide which is used to eliminate red leaks from the shorter-wavelength filters. The observing procedure is to place a star in one diaphragm with an area of adjacent sky in the other. Small systematic differences between the two beams are eliminated by periodically switching the star from one diaphragm to the other during an observation. The observer is aided by an oscilloscope display of the accumulated intensity as a function of polarizer position angle. For further information about the instrument, including a schematic diagram, see Dyck and Sandford (1971). Dyck, H.M and M.T. Sandford II, Multicolor polarimetry of some Mira variables, Astronomical Journal 76, 43-49, 1971. Shakhovskoy, N.M. and N.A. Dymov, Publ. Crimean Astrophys. Obs. 27, 291, 1962.