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First Performance Results of a New Field-Widened Spatial Heterodyne Spectrometer for Geocoronal Hα Research
Journal of Geophysical Research: Space Physics
  • D. D. Gardner, University of Wisconsin - Madison
  • E. J. Mierkiewicz, Embry-Riddle Aeronautical University
  • F. L. Roesler, University of Wisconsin - Madison
  • J. M. Harlander, Saint Cloud State University
  • K. P. Jaehnig, University of Wisconsin - Madison
  • S. M. Nossal, University of Wisconsin - Madison
  • L. M. Haffner, University of Wisconsin - Madison
Submitting Campus
Daytona Beach
Physical Sciences
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Publication/Presentation Date

A new, high-resolution field-widened spatial heterodyne spectrometer (FW-SHS) designed to observe geocoronal Balmer α (Hα, 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW-SHS observations were compared with an already well-characterized dual-etalon Fabry-Perot Interferometer (PBO FPI) optimized for Hα, also at PBO. The FW-SHS is a robust Fourier transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline (~10 times that of the PBO FPI) in a compact, versatile instrument with no moving parts.Coincident Hα observations by FW-SHS and PBO FPI were obtained over similar integration times, resolving powers (~67,000 and 80,000 at Hα) and fields of view (1.8° and 1.4°, respectively). First light FW-SHS observations of Hα intensity and temperature (Doppler width) versus viewing geometry (shadow altitude) show excellent relative agreement with the geocoronal observations previously obtained at PBO by FPI. The FW-SHS has a 640 km/s (14 Å) spectral band pass and is capable of determining geocoronal Hα Doppler shifts on the order of 100 m/s with a temporal resolution on the order of minutes. These characteristics make the FW-SHS well suited for spectroscopic studies of relatively faint (~12–2 R), diffuse-source geocoronal Hα emission from Earthˈs upper thermosphere and exosphere and the interstellar medium in our Galaxy. Current and future FW-SHS observations extend long-term geocoronal hydrogen observation data sets already spanning three solar minima. This paper describes the FW-SHS first light performance and Hα observational results collected from observing nights across 2013 and 2014.

American Geophysical Union
Citation Information
D. D. Gardner, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, et al.. "First Performance Results of a New Field-Widened Spatial Heterodyne Spectrometer for Geocoronal Hα Research" Journal of Geophysical Research: Space Physics Vol. 122 Iss. 1 (2017) p. 1373 - 1385
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