This composite photo shows how it might look as the WB-57F research aircraft chase the Aug. 21 solar eclipse.

(NASA/Faroe Islands/SwRI)

When a shrouds parts of the United States in darkness on Aug. 21, NASA will get a longer look at it than most, thanks to a pair of WB-57F jet planes.

The retrofitted planes will carry telescopes that'll get , known as the corona,according to a NASA release. Additionally, they'll be able to capture thermal images of Mercury for the first time to learn about varying temperatures on the planet's surface.

"These could well turn out to be the best ever observations of high-frequency phenomena in the corona,"Dan Seaton, co-investigator of the project and researcher at the University of ColoradoBoulder, said in the release. "Extending the observing time and going to very high altitude might allow us to see a few events or track waves that would be essentially invisible in just two minutes of observations from the ground."

A WB-57F jet is prepared for a test flight at NASA's Johnson Space Center in Houston; instruments are mounted under the silver casing on the plane's nose.

(NASA’s Johnson Space Center/Norah Moran)

In the seven minutes these planes will experience the eclipse – for most viewers on the ground, the eclipse won't even last two and a half – they'll capture 30 high-definition pictures of the corona each second, the release also said. It's one of 11 NASA-funded projects that'll take place , according to a separate NASA release.

The planes will take off from Houston's Ellington Field and will fly over Missouri, Illinois and Tennessee, according to NASA. They'll fly at a cruising altitude of 50,000 feet, where the sky is 20 to 30 times darker than on the ground and there's less turbulence to shake the telescopes while the high-quality images are captured.

"When the moon blocks out the sun during a total eclipse, those regions of Earth that are in the direct path of totality become dark as night for almost three minutes," Steve Clarke, director of the Heliophysics Division at NASA Headquarters in WashingtonD.C., said in the release. "This will be one of the best-observed eclipses to date, and we plan to take advantage of this unique opportunity to learn as much as we can about the sun and its effects on Earth."