LOUISVILLE, Ky. — A former NASA astrophysicist is speaking this week at the University of Louisville about next year’s total solar eclipse.

Fred Espenak has witnessed 26 total solar eclipses and has written about the phenomenon. He will discuss expectations for the Aug. 21 total eclipse, which will be visible from the contiguous United States for the first time since 1979.

The lecture is at 6:30 p.m. Thursday at the School of Music’s Comstock Hall.

The maximum viewpoint for the totality of the moon covering the sun will be near Hopkinsville. Viewers can expect a daytime twilight effect and a glimpse of the sun’s corona.

Espenak lives in Portal, Arizona, where he operates the Bifrost Astronomical Observatory and runs three eclipse-related websites. The American Astronomical Union named an asteroid after him in 2003.

This story has been corrected from an earlier version to show the spelling of Espenak’s first name is Fred.