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TANAGER: Design and Validation of an Automated Spectrogoniometer for Bidirectional Reflectance Studies of Natural Rock Surfaces
  • +4
  • Melissa Susanne Rice,
  • Kristiana Lapo,
  • Kathleen Hoza,
  • Edward Cloutis,
  • Michael D. Kraft,
  • Sean R Mulcahy,
  • Daniel Applin
Melissa Susanne Rice
Western Washington University

Corresponding Author:[email protected]

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Kristiana Lapo
Western Washington University
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Kathleen Hoza
First Mode, LLC
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Edward Cloutis
University of Winnepeg
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Michael D. Kraft
Western Washington University
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Sean R Mulcahy
Western Washington University
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Daniel Applin
UW
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Abstract

Laboratory measurements of reflectance spectra of rocks and minerals at multiple viewing geometries are important for interpreting spacecraft data of planetary surfaces. However, efficiently acquiring such measurements is challenging, as it requires a custom goniometer that can accommodate multiple, bulky samples beneath a movable light source and detector. Most spectrogoniometric laboratory work to date has focused on mineral mixtures and particulates, yet it is also critical to characterize natural rock surfaces to understand the influence of texture and alteration. We designed the Three-Axis N-sample Automated Goniometer for Evaluating Reflectance (TANAGER) specifically to rapidly acquire spectra of natural rock surfaces across the full scattering hemisphere. TANAGER has its light source and the spectrometer’s fiber optic mounted on motorized rotating and tilting arcs, with a rotating azimuth stage and six-position sample tray, all of which are fully motorized and integrated with a Malvern PanAnalytical ASD FieldSpec4 Hi-Res reflectance spectrometer. Using well-characterized color calibration targets, we have validated the accuracy and repeatability of TANAGER spectra. We also confirm that the system introduces no discernable noise or artifacts. All design schematics and control software for TANAGER are open-source and available for use and modification by the larger scientific community.
16 Apr 2024Submitted to ESS Open Archive
16 Apr 2024Published in ESS Open Archive