Abstract
We present the calibration status and data reduction methodology for the Wide Field Imager for Solar Probe (WISPR) on board the Parker Solar Probe (PSP) mission. In particular, we describe the process for converting a raw image, measured in digital numbers (DN), to a calibrated image, measured in mean solar brightness (MSB). We also discuss details of the on board image processing including bias removal, the linearity of the electronics, pointing, geometric distortion, and photometric calibration using stellar measurements, and the characterization of vignetting and other instrumental artifacts. The analysis presented here is based on data from the first four WISPR orbits. As the PSP perihelia get progressively closer to the Sun and the WISPR concept of operation evolves to deal with the brighter scene, the calibration will likely need to be updated. Aging of the optics and the possibility of detector degradation may also occur. Hence, we consider the WISPR calibration as work in progress with updates reported as necessary.
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Notes
See WISPR Website for a description of all the keywords in the WISPR FITS header.
Zemax is an optical modeling software.
SPICE is an observation geometry system for space science missions.
References
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Acknowledgements
We would like to thank the referee for many helpful suggestions to improve this article. Parker Solar Probe was designed, built, and is now operated by the Johns Hopkins Applied Physics Laboratory as part of NASA’s Living with a Star (LWS) program (contract NNN06AA01C). This work was supported by the NASA Parker Solar Probe Program Office for the WISPR program (contract NNG11EK11I). A.V. is supported by WISPR Phase E funds.
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Hess, P., Howard, R.A., Stenborg, G. et al. In-flight Calibration and Data Reduction for the WISPR Instrument On Board the PSP Mission. Sol Phys 296, 94 (2021). https://doi.org/10.1007/s11207-021-01847-9
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DOI: https://doi.org/10.1007/s11207-021-01847-9