Total Eclipse
On August 21, 2017, a total solar eclipse was visible to millions of Americans as it swept a narrow path across parts of the entire country. The USPS anticipated this rare event with a stamp celebrating the majesty of total solar eclipses. A total eclipse of the Sun occurs when the Moon completely blocks the visible solar disk from view, casting a shadow on the Earth. The image on the Total Eclipse of the Sun stamp shows a total solar eclipse that was seen over Jalu, Libya, in 2006.
The Total Eclipse of the Sun stamp is the first U.S. stamp to use thermochromic ink, which reacts to the heat of your touch. Placing your finger over the black disc on the stamp causes the ink to change from black to clear to reveal an underlying image of the moon. The image reverts back to the black disc once it cools. The back of the stamp pane shows a map of the eclipse path.