COLUMBIA — Astronomers and stargazing fans alike stood waiting in line inside Columbia’s post office Tuesday morning. They wanted to catch a preview of the upcoming total solar eclipse with the help of a stamp.

The post office began selling special edition, heat-activated stamps in celebration of the solar eclipse, which will take place on Aug. 21.

The stamps appear to be simple black circles on a background of gray and white sun rays. But the second warmth touches the stamp, a moon appears in the dark space.

Within four hours, the post office sold out of the stamps.

Customer service supervisor Shaun Smith ordered 100 sheets — with 16 individual stamps per sheet — in preparation of the sale. Smith said he sent in another order of 1,000 sheets, which is expected to arrive Monday. He would have ordered more, but there is a limit on how many can be ordered a single time.

Postmaster Mark S. Rask said he and Smith plan on ordering a “couple thousand” more sheets because they expect continued excitement and don’t want to sell out again. Rask bought a few sheets for himself, wanting to have some on hand for reference.

“I think they’re really cool,” Rask said as he placed his thumb beneath the paper to activate the heat sensitive stamp. “It’s always great to do a fun stamp that people will get excited for.”

A special sleeve to protect the stamps can also be purchased for those who wish to collect the stamp or save it as a keepsake.

The stamps are still available to order online at the USPS website.

The post office will also reveal a second special edition stamp on the day of the eclipse. The unveiling will occur at 11 a.m. on Aug. 21 at Cosmopolitan Park. Other solar eclipse events can be found online at comoeclipse.com, including a free “Totality Music Fest” featuring the Ben Miller Band.

Supervising editor is Hannah Black.