CCD Imaging/Spectropolarimeter


The CCD Imaging/Spectropolarimeter combines polarizing optics and a transmission-optics spectrograph into a self-contained, portable, and extremely high-throughput instrument. It was designed and constructed in 1990-91 by Gary Schmidt and H.S. Stockman (STScI). The polarimeter section is a dual-beam design which incorporates rotating achromatic waveplates and a full-aperture Wollaston prism. The detector is a 1200x800 pixel Loral CCD with quantum efficiency enhanced through UV-flooding and an antireflection coating of hafnium oxide. With current gratings, spectral resolutions of 4-15A are available over a range in useful spectral response of 3800-9000A. The detection of linear or circular polarization at a level p < 0.05% is possible. In the imaging mode, polarization maps can be obtained in filtered bandpasses at the seeing limit over a field of view 51" square at the 2.3-m or 19" square at the MMT. The polarimeter is a standalone instrument with a dedicated CCD, camera controller, instrument computer, and comparison lamp system. Optimized for an f/9 beam, CCD SPOL can be mounted directly on the Steward Observatory 2.3-m telescope or the 6.5-m converted MMT, and has been adapted for use at the 4-m Mayall telescope on Kitt Peak, the 74" Mt. Stromlo reflector, the 1.9-m Perkins telescope at Lowell Observatory, and the 1.51-m telescope atop Mt. Bigelow.

CCD SPOL is a PI (Private-Investigator) instrument, available for use through arrangement and collaboration with Gary Schmidt and Paul Smith

Left: Total and circularly polarized  flux spectra of the 150MG magnetic cataclysmic variable V884 Her.  The bottom panel presents calculated cyclotron polarization spectra for various angles to the magnetic field direction.  The polarization peak around 7300A is the cyclotron fundamental - the first time this has been seen from a white dwarf. From Schmidt, Ferrario, Wickramasinghe, & Smith (2001)

Right: Total and linearly polarized flux spectra of the highly polarized 2MASS QSO 2M151653+1900, showing a highly polarized spectrum in total flux which lacks the narrow emission lines in scattered light.  From Smith, Schmidt, Hines, Cutri & Nelson (2000).


SPOL publications

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