Daniel K. Inouye Solar Telescope
World's largest solar telescope, observing the Sun in visible to near-infrared.
Last updated
The world’s largest solar telescope sits atop the Haleakalā volcano on Maui, Hawaii. Originally called the Advanced Technology Solar Telescope (ATST), it was renamed in 2013 for Daniel K. Inouye, a former U.S. Senator from Hawaii. The facility, known as the Daniel K. Inouye Solar Telescope (DKIST), has a 4-meter aperture and is designed to study the Sun across visible and near-infrared wavelengths. Funding comes from the National Science Foundation, with management by the National Solar Observatory.
Construction
Total project costs reached $344.13 million, and the telescope is a joint effort among many research institutions. Test images were released in January 2020, and construction wrapped up in November 2021, when the telescope transitioned into scientific operations. Its first science observations began on February 23, 2022, kicking off a year-long commissioning phase. Since 2018, there have been repeated calls to rename the telescope after allegations of sexual misconduct by Senator Inouye came to light.
Main telescope structure
The telescope’s primary mirror measures 4.24 meters across but only a 4-meter off-axis section is used, with the outer 12 centimeters masked. This off-axis Gregorian design eliminates a central obstruction, cutting down on scattered light and making adaptive optics and digital image reconstruction—like speckle imaging—easier to run. The 75-millimeter-thick f/2 mirror was cast from Zerodur by Schott, polished at the University of Arizona’s Richard F. Caris Mirror Laboratory, and aluminized at the AMOS facility.
A 0.65-meter secondary mirror, made of silicon carbide and mounted on a hexapod, adjusts for thermal expansion and structural bending to stay in optimal position. Adaptive optics correct for atmospheric blurring, letting the telescope resolve features as small as 20 kilometers on the Sun. A deformable mirror and wavefront sensor work together in real time to fix distortions, while an active optics system keeps the mirrors aligned and focused using sensors and actuators.
The site on Haleakalā was chosen for its clear daytime weather and good atmospheric seeing. Construction began in January 2013 after a contract was awarded in 2010, with an original completion target of 2017. The telescope housing was finished by September 2013, and the primary mirror arrived on site in early August 2017.
Quick Facts
- Location
- Maui, Hawaii, US
Facts from the source article.
Background
Known as the Advanced Technology Solar Telescope (ATST) until 2013, it was named after Daniel K. Inouye, a US Senator for Hawaii. The contract to build the telescope was awarded in 2010, with a then-planned completion date of 2017. Physical construction at the DKIST site began in January 2013, and work on the telescope housing was completed in September 2013.
The primary mirror was delivered to the site the night of 1–2 August 2017 and the completed telescope provided images of the sun in unprecedented detail in December 2019. Completion of construction and transition into operational phase with the first scientific observations was announced on November 22, 2021. At the time, the telescope had been over 25 years in the making.
The DKIST has a 4.24-meter primary mirror in an off-axis Gregorian configuration that provides a 4-meter clear, unobstructed aperture. The off-axis, clear aperture design avoids a central obstruction, minimizing scattered light.
Adaptive optics correct for atmospheric distortions and blurring of the solar image, which enables high-resolution observations of features on the Sun as small as 20 km. The site on the Haleakalā volcano was selected for its clear daytime weather and favourable atmospheric seeing conditions. Since 2018, there have been numerous calls to rename the telescope due to the discovery of Senator Inouye's alleged sexual misconduct.
Frequently Asked Questions
What is Daniel K. Inouye Solar Telescope known for?
Armed with a 4-meter aperture and a 4.24-meter primary mirror, DKIST observes the Sun across visible and near-infrared wavelengths to investigate magnetic fields, flares, and coronal dynamics. It is the most powerful solar observatory ever constructed.
Where does Daniel K. Inouye Solar Telescope call home?
The telescope is situated at Haleakalā Observatory atop the Haleakalā volcano in Maui, Hawaii, where the high elevation and thin atmosphere provide exceptionally stable viewing conditions. This makes it one of the best solar-observation sites on Earth.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Daniel K. Inouye Solar Telescope (CC BY-SA 4.0).
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