The Wide-Field Imager for Solar Probe (WISPR) is an imaging instrument of the ''

Parker Solar Probe The Parker Solar Probe (PSP; previously Solar Probe, Solar Probe Plus or Solar Probe+) is a NASA space probe launched in 2018 to make observations of the Stellar corona, Sun's outer corona. It used repeated Gravity assist, gravity assists from ...

'' mission to the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

, launched in August 2018. Imaging targets include visible light images of the

corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun or another star * Corona (beer), a Mexican beer * Corona, informal term for the coronavirus or disease responsible for the COVID-19 ...

solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...

, shocks, solar ejecta, etc. Development of WISPR was led by the

U.S. Naval Research Laboratory The United States Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps. Located in Washington, DC, it was founded in 1923 and conducts basic scientific research, appl ...

. The ''Parker Solar Probe'' with WISPR on board was launched by a

Delta IV Heavy The Delta IV Heavy (Delta 9250H) was an expendable heavy-lift launch vehicle, the largest type of the Delta IV family. It had the highest capacity of any operational launch vehicle in the world after the retirement of the Space Shuttle in 20 ...

on 12 August 2018 from

Cape Canaveral Cape Canaveral () is a cape (geography), cape in Brevard County, Florida, in the United States, near the center of the state's Atlantic Ocean, Atlantic coast. Officially Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated ...

, Florida. WISPR is intended take advantage of the spacecraft's proximity to the Sun by taking

coronagraph A coronagraph is a telescopic attachment designed to block out the direct light from a star or other bright object so that nearby objects – which otherwise would be hidden in the object's bright glare – can be resolved. Most coronagr ...

-style images of the solar corona and features like coronal streamers, plumes, and

mass ejections Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary partic ...

. One of the goals is to better understand the structure of the solar corona near the Sun. WISPR is designed to study the

electron density Electron density or electronic density is the measure of the probability of an electron being present at an infinitesimal element of space surrounding any given point. It is a scalar quantity depending upon three spatial variables and is typical ...

and velocity structure of the corona. The instrument field of view is planned to extend from 13 to 108 degrees away from the Sun, and does not directly image the Sun; the area of interest is a very wide field extending away from the Sun. WISPR includes two separate telescopes, each with a

radiation-hardened Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation (particle radiation and high-energy electromagnetic radiation), especially for environm ...

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss ", , ) is a type of MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...

imager with resolution of 2,048×1,920 pixels. The CMOS sensors are an

active pixel sensor An active-pixel sensor (APS) is an image sensor, which was invented by Peter J.W. Noble in 1968, where each pixel sensor unit cell has a photodetector (typically a pinned photodiode) and one or more active transistors. In a metal–oxide–semico ...

type of detector. The two telescopes are designated WISPR-Inner (WISPR-I) and WISPR-Outer (WISPR-O), with WISPR-I observing at

angles Angles most commonly refers to: *Angles (tribe), a Germanic-speaking people that took their name from the Angeln cultural region in Germany *Angle, a geometric figure formed by two rays meeting at a common point Angles may also refer to: Places ...

13°–53° away from the Sun and WISPR-O viewing elongations of 50°–108°. Both telescopes observe at both visible and

near-infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of ...

wavelengths, with

bandpass filter A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects ( attenuates) frequencies outside that range. It is the inverse of a '' band-stop filter''. Description In electronics and s ...

s of 490–740 nm and 475–725 nm on WISPR-I and WISPR-O, respectively. The WISPR first light image was published in September 2018. In December, a view of the corona including a coronal streamer was released. In November 2018, a video of WIPSR recording solar wind during the spacecraft's first close pass to the Sun was released. One project scientist noted, "The data we’re seeing from Parker Solar Probe’s instruments is showing us details about solar structures and processes that we have never seen before."

Development

The

stray light Stray light is light in an optical system which was not intended in the design. The light may be from the intended source, but follow paths other than intended, or it may be from a source other than that intended. This light will often set a worki ...

and baffle for WISPR was modeled during development of the instrument. Two noted cases where stray material caused issue with space imaging includes the Infrared Telescope (IRT) flown on the Space Shuttle

Spacelab Spacelab was a reusable laboratory developed by European Space Agency (ESA) and used on certain spaceflights flown by the Space Shuttle. The laboratory comprised multiple components, including a pressurized module, an unpressurized carrier, ...

-2 mission, in which a piece of

mylar BoPET (biaxially oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical stability, dimensional stability, transparency reflectivity, an ...

insulation broke loose and floated into the line-of-sight of the telescope corrupting data. This was on the

STS-51-F STS-51-F (also known as Spacelab 2) was the 19th flight of NASA's Space Shuttle program and the eighth flight of Space Shuttle ''Challenger''. It launched from Kennedy Space Center, Florida, on July 29, 1985, and landed eight days later on Au ...

in the year 1985. Another case was in the 2010s on the Gaia spacecraft for which some stray light was identified coming from fibers of the sunshield, protruding beyond the edges of the shield.

Gallery

File:WISPR first light image.png, WISPR first light image. The right portion of the image is from WISPR's inner telescope, which is a 40-degree field of view and begins 58.5 degrees from the Sun's center. The left portion is from the outer telescope, which is a 58-degree field of view and ends about 160 degrees from the Sun. File:Parker-view-of-earth.jpg, The view from the probe's WISPR instrument on Sept. 25, 2018, shows Earth, the bright sphere near the middle of the right-hand panel. The elongated mark toward the bottom of the panel is a lens reflection from the WISPR instrument File:Parker Solar Probe coronal stream wispr-big 1-st flyby.jpg, Photo from the WISPR shows a coronal streamer, seen over the east limb of the Sun on Nov. 8, 2018, at 1:12 a.m. EST. The fine structure of the streamer is very clear, with at least two rays visible. Parker Solar Probe was about 16.9 million miles from the Sun's surface when this image was taken. The bright object near the center of the image is Mercury, and the dark spots are a result of background correction. File:Wispr merged six planets.jpg, When Parker Solar Probe was making its closest approach to the Sun on June 7, 2020, WISPR captured the planets Mercury, Venus, Earth, Mars, Jupiter and Saturn in its field of view File:Venus-ParkerSolarProbe-July2020.jpg, Photo taken by the probe during its second

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

flyby, July 2020 File:Parker Solar Probe flew by Venus on its fourth flyby.gif, As Parker Solar Probe flew by Venus on its fourth flyby, its WISPR instrument captured these images, showing the nightside surface of the planet File:Parker Solar Probe Encounters Streamers on the Way to the Sun.webm, As the probe passed through the Sun's corona in early 2021, it flew by structures called coronal streamers

References

External links

Looking at the Corona with WISPR on Parker Solar Probe
(April 16, 2018) {{Psp Parker Solar Probe Space imagers Solar telescopes

Development

Gallery

See also

References

External links