A Shining Moment for USPS’s Gaze at a Dark Day — August 21, 2017

The United States Postal Service has gone all out for the Total Eclipse of the Sun, which will occur August 21 from the northwest corner of the continental U.S. to South Carolina’s Atlantic Coast in the southeast. The moon on Monday will come between the Earth and sun. A shadow will totally block the sun from our sight for a 70-mile-wide path across the country. Those outside the path of totality will experience a partial solar eclipse.

This is the first time a total solar eclipse has been visible in the U.S. since 1979 and it’s the first time in 99 years such an eclipse as occurred entirely across the Lower 48, according to space.com. Several locales in Tennessee — such as Gallatin, Lebanon and Madisonville — get close to the maximum duration of totality, about 2 minutes and 40 seconds.

“One astronomer has said it will be the ‘most photographed, most shared, most tweeted event in human history,’ ” the Washington Post said in a recent story.

This special occasion called for a special stamp.

On June 20, the Summer Solstice, the USPS issued a first-ever stamp with changeable ink. The forever stamp, currently sold at 49 cents and forever valid for first-class domestic mail, has a darkened orb — such as an eclipsed sun — but when heated (such as under a thumb) turns into the face of the moon.

Post offices along the path have planned special events or postal cancellations for the eclipse. An interactive map from the U.S. Postal Service shows the swath of the eclipse and all of the post offices directly in its path.

The stamp uses thermochromic ink to create its special effect. The dark, round image of the eclipse on the stamp transforms into the illuminated moon from the heat of a finger. The image turns black again when it cools. This is the first time such ink has been used on a U.S. stamp, according to the Postal Service.

The Postal Service warns that thermochromic inks are vulnerable to UV light and should be kept out of direct sunlight as much as possible to preserve this special effect. To help ensure longevity, the Postal Service is offering a special dark envelope to hold and protect the stamp pane for 25 cents. The special ink also causes a full 16-stamp pane of the stamps to be slightly crinkled. Banknote Corporation of America printed the stamp and CTI, a specialized ink printer based in Colorado Springs, Colorado, added the thermochromic ink.

The Eclipse stamp was released on June 20 and celebrated with a first-day ceremony at the Art Museum of the University of Wyoming in Laramie. Taking part in the ceremony were NASA astrophysicist Madhulika “Lika” Guthakurta, University of Wyoming Department of Physics and Astronomy Professor Chip Kobulnicky, and astrophysicist Fred Espenak, known as “Mr. Eclipse,” joined the Postal Service for the first-day-of-issue ceremony.

The Solar Eclipse forever stamp is issued in a pane of 16. Art director Antonio Alcalá of Alexandria, Virginia, designed the stamp. The stamp features a photograph of an eclipse taken by Espenak on March 29, 2006 in Jalu, Libya.

Espenak, of Portal, Arizona, is a retired NASA astrophysicist and is considered by many to be the world’s leading authority on total solar eclipses with 27 under his belt.

A total solar eclipse provides us with the only chance to see the sun’s corona — its extended outer atmosphere — without specialized instruments. During the total phase of an eclipse the corona appears as a gossamer white halo around the black disk of the moon, resembling the petals of a flower reaching out into space.

Tens of millions of people in the United States hope to view this rare event, which has not been seen on the U.S. mainland since 1979. The eclipse will travel a narrow path across the entire country for the first time since 1918.

“With the release of these amazing stamps using thermochromic ink, we’ve provided an opportunity for people to experience their own personal solar eclipse every time they touch the stamps,” said Jim Cochrane, chief customer and marketing officer for the USPS, who took part in the first-day ceremony. “As evidenced by this stamp and other amazing innovations, the Postal Service is enabling a new generation to bridge the gap and tighten the connection between physical mail and the digital world.”

A total eclipse of the sun occurs when the moon completely blocks the visible solar disk from view, casting a shadow on Earth.

On the back of the pane is a map of the United States showing the path of totality, those places where the sun will be completely blocked as the moon passes between it and Earth. “The 70-mile-wide shadow path of the eclipse, known as the path of totality, will traverse the country diagonally, appearing first in Oregon (mid-morning local time) and exiting some 2,500 miles east and 90 minutes later off the coast of South Carolina (mid-afternoon local time),” the pane says.

Guthakurta warned that only people within the path of totality should view the eclipse with the naked eye.

“The sun can be viewed safely with the unaided eye only during the few brief seconds or minutes of a total solar eclipse,” said Guhathakurta. “Partial eclipses or partial phases of total solar eclipses are never safe to watch without solar eclipse glasses.”

Guthakurta recommended learning more on solar eclipse safety, educational and science information at eclipse2017.nasa.gov.

According to the timeanddate.com website, here are a few times of totality from west to east, all listed in local time and rounded to the nearest minute: Bend, Oregon, 10:20 a.m.; Idaho Falls, Idaho, 11:33 a.m.; Lincoln, Nebraska, 1:03 p.m.; St. Louis, Missouri, 1:18 p.m.; Nashville, Tennessee, 1:28 p.m.; and Charleston, South Carolina, 2:47 p.m.