The U.S. Postal Service is releasing its first “thermochromic ink” stamp to commemorate August’s all-American eclipse.

Rub the stamp, which features a photo of a total eclipse of the sun, and the heat from your finger will reveal a photo of the moon.

Both images were taken by astrophotographer Fred Espenak of Portal, Arizona.

Espenak is excited about the stamp, even more so about the eclipse, which will traverse the United States from Oregon to South Carolina.

Espenak has observed total eclipses on seven continents. His wife, Patricia, is also a total-eclipse aficionado. The couple met 20 years ago while viewing an eclipse in India.

The August event will be a great opportunity to interest larger numbers of Americans in eclipses and astronomy, Espenak said.

He expects folks from across the country to travel to the path of totality.

“It’s great to have one in our backyard,” he said.

Fred will travel 1,066.7 miles for his “backyard” experience, viewing the all-American eclipse on Aug. 21 from a gathering in Casper, Wyoming.

That’s still much closer than some of his eclipse jaunts. In 2003, he boarded an icebreaker to catch the path of an eclipse in Antarctica.

Patricia Espenak will travel 1,557.5 miles to view the eclipse with the couple’s two granddaughters in Corvallis, Oregon. Fred Espenak said the girls, 8 and 11 years old, have already been “indoctrinated” into the eclipse cult.

Solar astronomer Matt Penn was enthusiastic about the stamp, which will be released June 20, the date of the summer solstice.

Penn, of the National Solar Observatory, is leading a campaign that has enlisted hundreds of students and amateur astronomers to make a movie of the all-American eclipse. He said the event is an opportunity for millions of Americans to learn about solar science.

“The upcoming eclipse is very exciting, and it gives solar physicists a chance to show a lot of taxpayers exactly what we study,” he said.

“During totality, millions of people will be able to see the solar corona, sculpted into beautiful shapes by the sun’s magnetic field,” he said.

The corona, the plasma surrounding the sun, is usually unseeable, but becomes visible during a total eclipse to those under the full shadow of the moon.

The National Solar Observatory’s Citizen CATE experiment will station 60 telescopes along the path of the eclipse to make a 90-minute movie of the corona.

Contact: tbeal@tucson.com or 573-4158. Follow him on Facebook or on Twitter: @bealagram

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