Sundials - World's Oldest Clocks

North American Sundial Society

The 2017 August 21st solar eclipse will be commemorated by the US Postal Service with a unique thermochromic ink Forever Stamps: the stamp shows the total Eclipse of the Sun with its corona blocked by a black disk of the moon.  However, using the body heat of your thumb or fingers the eclipse image will reveal an underlying image of the moon. The image reverts back to the eclipse once it cools. Fred Espenak, "Mr. Eclipse" a retired NASA astrophysicist, took the photograph of both the eclipse (from Jalu, Libya on March 29, 2006) and the full moon.

The USPS  states that June 20, 1:30 p.m. MT will be theFirst-Day-of-Issue ceremony, taking place at the Art Museum of the University of Wyoming (UW) in Laramie. The University is celebrating the summer solstice on June 20. Prior to the stamp issuance, visitors are encouraged to arrive at UW's Art Museum's Rotunda at 11:30 a.m. to witness a unique architectural feature at noon when a single beam of sunlight shines from down on a silver dollar embedded in the floor, marking noon on the summer solstice,

The Total Eclipse of the Sun Forever Stamps may be pre-ordered at usps.com/shop in early June for delivery following the June 20 nationwide issuance.  The back of the stamp pane provides a map of the eclipse path and times it appears at cities across the US.

Back Panel of the Eclipse Stamp

Read more at: NASA Eclipse    and for observing tips  http://www.mreclipse.com/SEphoto/SEphoto.html