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Proceedings Paper

Attenuation of direct solar radiation by a perforated plate for on-orbit visible calibration
Author(s): James C. Bremer; H. John Wood; Guojun Si
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Paper Abstract

Attenuated sunlight is a valuable reference for on-board calibration of spacebome instruments that observe reflected sunlight from the earth. Direct viewing of the sun through a perforated plate can provide full aperture, end-to-end calibration. Since the transmissivity of the perforated plate depends only upon its geometry, it is potentially more stable than the diffuse reflectivity of a diffuser plate, particularly when exposed to the space environment. We have observed the sun through a sheet metal plate with a hexagonal array of small holes placed in front of a telescope. A pinhole in the telescope’s focal plane, followed by a spectral filter and a silicon photo-diode, were selected to approximate the IFOV and spectral bands proposed for imagers on future GOES missions. In each observation, the center of the solar image was found to have a smooth, symmetrical maximum, with no significant angular structure due to interference. These observations demonstrated that the perforated plate technique is a promising method for stable, long-term, on-orbit calibration of visible and near IR channels on spacebome optical instruments.

Paper Details

Date Published: 15 November 2000
PDF: 10 pages
Proc. SPIE 4135, Earth Observing Systems V, (15 November 2000); doi: 10.1117/12.494249
Show Author Affiliations
James C. Bremer, Swales Aerospace (United States)
H. John Wood, NASA Goddard Space Flight Ctr. (United States)
Guojun Si, Swales Aerospace (United States)


Published in SPIE Proceedings Vol. 4135:
Earth Observing Systems V
William L. Barnes, Editor(s)

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