  The Wide-field Imager for Solar Probe (WISPR) onboard Parker Solar Probe
(PSP), observing in white light, has a fixed angular field of view, extending
from 13.5 degree to 108 degree from the Sun and approximately 50 degree in the
transverse direction. In January 2021, on its seventh orbit, PSP crossed the
heliospheric current sheet (HCS) near perihelion at a distance of 20 solar
radii. At this time, WISPR observed a broad band of highly variable solar wind
and multiple coronal rays. For six days around perihelion, PSP was moving with
an angular velocity exceeding that of the Sun. During this period, WISPR was
able to image coronal rays as PSP approached and then passed under or over
them. We have developed a technique for using the multiple viewpoints of the
coronal rays to determine their location (longitude and latitude) in a
heliocentric coordinate system and used the technique to determine the
coordinates of three coronal rays. The technique was validated by comparing the
results to observations of the coronal rays from Solar and Heliophysics
Observatory (SOHO) / Large Angle and Spectrometric COronagraph (LASCO)/C3 and
Solar Terrestrial Relations Observatory (STEREO)-A/COR2. Comparison of the
rays' locations were also made with the HCS predicted by a 3D MHD model. In the
future, results from this technique can be used to validate dynamic models of
the corona.
