The Buhl Planetarium and Institute of Popular Science Building, also known as the "People's Observatory", is located at 10 Children's Way in the Allegheny Center neighborhood of Pittsburgh, Pennsylvania.

[5] The building was named after Henry Buhl, Jr. and was designed by architects Ingham, Pratt & Boyd in the "stripped Classical style" and featured an octagonal copper dome that housed the projector.

[9] The Buhl Planetarium was the first building of its type to have a special sound system for the hearing-impaired in its operating theater.

[10] The planetarium also housed a thirty-five foot long Foucault pendulum[11] and a ten-inch, Siderostat-type, refractor telescope (now the second largest of its type).

In 1994, the Annex closed and all programming moved to the CSC, while the Carnegie Museums of Pittsburgh sought a new use or owner for the building.