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Article
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
Department
Physical Sciences
Document Type
Article
Publication/Presentation Date
1-1-2017
Abstract/Description

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.

DOI
https://doi.org/10.1002/2016JA022625
Publisher
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
Available at: http://works.bepress.com/l-m-haffner/11/