Upcoming shows: The National Building Museum, which is the first museum devoted to the nation's architectural heritage, opens Thursday with a show called "Building a National Image: Architectural Drawings for the American Democracy." The museum is housed in the old Pension Building, and this first exhibition runs through Feb. 2. Information: 272-2448.

Also opening Thursday, at the National Air and Space Museum, is an exhibition showing how different cultures have depicted comets. Titled "Fire and Ice," it consists of 90 pieces of art and artifacts, which will be on display in the "Flight and the Arts" gallery. Information: 357-2700.

The National Museum of American Art Thursday opens a show called "Art, Design and the Modern Corporation: The Collection of the Container Corporation of America. Information: 357-2700

Opening Saturday at the Corcoran Gallery of Art, "The New York School: Photographs 1935-1963 . . . Opening Sunday at the National Gallery of Art, "Du rer to Delacroix: Great Master Drawings from Stockholm . . . Nov. 22 at the National Portrait Gallery, "Gaston Lachaise: Portrait Sculptures."

Also Nov. 22 at the National Museum of American Art: "Photographs of Fine Art: Peter A. Juley and Son." Juley and Son ran a photographic studio in New York, established in 1896. The museum purchased 127,000 negatives from the studio, reportedly the largest single photographic record of American art extant. The collection includes 4,500 portraits of artists.

Sidney Lawrence, public affairs officer at the Hirshhorn Museum and Sculpture Garden, will give a lecture, "Sculpture Gardens: A New Tradition," Sunday in the museum's auditorium. Lawrence is coauthor of the book "Music in Stone: Great Sculpture Gardens of the World." Information: 357-2700 . . . The National Museum of American History is presenting a season of music, from rhythm and blues to chamber music. For details call 357-2700 . . . Through Saturday at the French Embassy the photographs of pioneer photographer Lucien Aigner are on display in a show called "Paris, Fifty Years Later." Information: 944-6000.

* Starting tomorrow, the backstage column will appear Tuesdays.