In-flight Calibration and Data Reduction for the WISPR Instrument On Board the PSP Mission

Hess, Phillip; Howard, R. A.; Stenborg, G.; Linton, M. G.; Vourlidas, A.; Thernisien, A.; Colaninno, R. C.; Rich, N.; Wang, Dennis; Battams, K.; Kuroda, Natsuha

doi:10.1007/s11207-021-01847-9

Cited by 13 publications

(15 citation statements)

References 31 publications

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“…The images were down-linked to Earth 2 × 2 binned (i.e., with a size of 960 × 1024 pixel 2 , which corresponds to a plate scale of 2 54 for WISPR-I and 3 39 for WISPR-O). The WISPR calibration procedures are described in Hess et al (2021).…”

Section: Observationsmentioning

confidence: 99%

“…The latter includes the instrumental straylight, and the star field. According to Hess et al (2021), WISPR-I stray-light is negligible up to the S/C heliocentric distances covered in Orbits 1 through 5. We have reassessed the stray-light level of WISPR-I images obtained during Encounters 7 through 10 following the same approach detailed in Paper I and found that it remains negligible.…”

Section: Observationsmentioning

confidence: 99%

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PSP/WISPR Observations of Dust Density Depletion near the Sun. II. New Insights from within the Depletion Zone

Stenborg

Howard

Vourlidas

et al. 2022

ApJ

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Visible light observations from the Wide-field Imager for Solar PRobe (WISPR) aboard the Parker Solar Probe (PSP) mission offer a unique opportunity to study the dust environment near the Sun. The existence of a dust-free zone (DFZ) around stars was postulated almost a century ago. Despite numerous attempts to detect it from as close as 0.3 au, observational evidence of a circumsolar DFZ has remained elusive. Analysis of WISPR images obtained from heliocentric distances between 13.3–53.7 R ⊙ over multiple PSP orbits shows a gradually decreasing brightness gradient along the symmetry axis of the F-corona for coronal heights between 19 and 9 R ⊙. Below 9 R ⊙, the gradient reverses its trend, approaching the radial dependence exhibited at heights above 19 R ⊙. After taking into account the effects of both the electron corona background and the nonresolved starlight, the WISPR observations down to 4 R ⊙ are consistent with forward-modeling simulations of the F-corona brightness within [−6, 5]% if a circumsolar region of depleted dust density between 19 and 5 R ⊙ enclosing a DFZ is considered. In addition, we show, for the first time, that the F-corona brightness inward of about 15 R ⊙ depends on the observer’s location for observing distances below 35 R ⊙.

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Section: Observationsmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

PSP/WISPR Observations of Dust Density Depletion near the Sun. II. New Insights from within the Depletion Zone

Stenborg

Howard

Vourlidas

et al. 2022

ApJ

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“…The WISPR images of Venus are processed using the standard Level 2 pipeline described in Hess et al. ( 2021 ). This processing removes the APS detector column to column bias pattern and corrects and normalizes the images so that the resulting data are consistent, regardless of the exposure time and gain setting used for a given image.…”

Section: Observationsmentioning

confidence: 99%

Parker Solar Probe Imaging of the Night Side of Venus

Wood

Hess

Lustig‐Yaeger

et al. 2022

Geophysical Research Letters

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Although Venus is the brightest planet in the sky, its surface was long a mystery due to the opacity of its thick atmosphere. Optical images of the planet show a featureless white disk, dominated by scattered sunlight from the impenetrable atmosphere. Radar imaging from Earth provided the first means to see the surface (e.g., Goldstein et al., 1976;Rogers & Ingalls, 1969), but detailed mapping had to await the arrival of orbiting spacecraft with radar capabilities, particularly Magellan (e.g., Solomon et al., 1992).Starting with the work of Allen and Crawford (1984), it was found that it was possible to penetrate the thick Venusian atmosphere by observing nightside thermal emissions in the near infrared (NIR), providing a means to study both the surface and lower atmosphere (

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“…of the field has increased substantially, requiring experimentation and subsequent reduction of exposure times to avoid saturation. These issues are discussed in more detail by Hess et al (2021). Here, as opposed to explicitly stating the observing parameters for all nine encounters thus far, we will instead refer to that publication and the WISPR project website, 8 from which so-called "summary files"-plain text metadata for all recorded observations-are readily available.…”

Section: Wispr Observationsmentioning

confidence: 99%

“…In Paper I, we studied observations recorded by WISPR-I on 2018 November 5, during PSPʼs first solar encounter, noting that a small portion of the dust trail was visible in WISPR-O, but was not considered at that time due to ongoing calibrations regarding the WISPR-O data. Since that time, the calibration procedures for WISPR-O have been finalized and published (Hess et al 2021) and a Level-3 (L3) data product for WISPR-O is routinely produced, thus enabling us to extend our investigation to this camera. This is fortuitous as the dust trail is now better observed in WISPR-O than WISPR-I, primarily because the evolving orbit of PSP has shifted the timing of our close approach to the trail to coincide with the trail's passage through WISPR-O, particularly since Encounter 4.…”

Section: Wispr Observationsmentioning

confidence: 99%

Continued PSP/WISPR Observations of a Phaethon-related Dust Trail

Battams

Gutarra-Leon

Gallagher

et al. 2022

ApJ

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We present an update to the first white-light detections of a dust trail observed closely following the orbit of asteroid (3200) Phaethon, as seen by the Wide-field Imager for the Parker Solar Probe instrument on the NASA Parker Solar Probe mission. Here, we provide a summary and analysis of observations of the dust trail over nine separate mission encounters between 2018 October and 2021 August that saw the spacecraft approach to within 0.0277 au of the orbit of Phaethon. We find the photometric and estimated dust mass properties to be in line with those in the initial publication, with a visual (V) magnitude of V ∼ 16.1 ± 0.3 pixel−1, corresponding to a surface brightness of 26.1 mag arcsec−2, and an estimated mass of dust within the range 1010–1012 kg depending on the assumed dust properties. However, the key finding of this survey is the discovery that the dust trail does not perfectly follow the orbit of Phaethon, with a clear separation noted between them that increases as a function of true anomaly, though the trail may differ from Phaethon’s orbit by as little as 1° in periapsis.

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In-flight Calibration and Data Reduction for the WISPR Instrument On Board the PSP Mission

Cited by 13 publications

References 31 publications

PSP/WISPR Observations of Dust Density Depletion near the Sun. II. New Insights from within the Depletion Zone

PSP/WISPR Observations of Dust Density Depletion near the Sun. II. New Insights from within the Depletion Zone

Parker Solar Probe Imaging of the Night Side of Venus

Continued PSP/WISPR Observations of a Phaethon-related Dust Trail

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