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Allegheny Observatory restoration reminds of its history

John Conti
| Saturday, March 1, 2014, 9:00 p.m.

Great old buildings acquire meaning over time, particularly when they vividly recall for us the ambitions and accomplishments of the people who built them.

It's that way with the Allegheny Observatory, which embodies the dreams of two great Pittsburgh scientists of the 19th century — Samuel P. Langley and John A. Brashear — and the efforts of industrialists like William Thaw, Andrew Carnegie and George Westinghouse, who supported their work.

The 102-year-old observatory sits atop what has, for a long time, been known simply as Observatory Hill. It's at the summit of Riverview Park above the North Side, and it has a commanding view all around — of the city and of the sky.

Built with three rotating telescope domes and rendered in a restrained Classical style, it is undergoing a slow but steady architectural restoration that promises to bring back its early grandeur.

The building has at least two lessons to teach us. One is about the painstaking efforts involved in architectural restoration. The other is to remind us of Langley, who in the last half of the 19th century helped create the science of astrophysics and was a pioneer of aviation, and Brashear, who became one of the world's leading makers of telescopes and optics.

Owned and operated by the University of Pittsburgh, the observatory is today used partly for teaching, but also in the current hunt to find planets circling stars. By measuring subtle shifts in the brightness of stars, Pitt astronomers can find evidence of orbiting planets. They use an up-to-date modern telescope at the observatory that can be controlled remotely from the Pitt campus in Oakland.

The observatory is open for tours and is particularly attractive for younger high-school and elementary students awakening to the wonderments of planets and stars. On clear nights, they can look through one of the powerful historic telescopes in the building.

Exterior restoration is being done in phases, funded partly by Pennsylvania state historic preservation grants. The work has been a major project for the last eight years of Jeff Slack, a planner and preservationist with Pfaffmann+Associates, a Downtown architectural firm responsible for restoration. Slack also teaches historic preservation at Pitt, and, this year, is including the observatory in his students' studies.

So far, the pediment that crowns the entrance and the paired Ionic columns and pilasters that frame the front door have been restored. This involved molding glass-fiber-reinforced concrete to the exact specifications of the original terra cotta ornament and using it to replace deteriorated pieces. On the columns, a different type of modern concrete that matched the original was used.

The restoration emphasizes authenticity. After research identified the long-defunct firm that made the terra cotta more than 100 years ago, Slack was able to locate 26 original shop drawings of the observatory's ornament at the National Building Museum in Washington, D.C.

Most of the building was built of tan-colored Kittanning brick, with the terra cotta trim and an exposed sandstone foundation. Structural steel supports the telescopes and three domes.

Additional work will involve doing complete measured drawings of the exterior, much more repair of molding and trim throughout the exterior, then masonry repointing and repair. The observatory was designed by turn-of-the century Pittsburgh architect Thorsten Billquist,

The building was the brainchild of John Brashear, for whom today's Brashear High School is named. He began working with Langley in an earlier observatory building (situated farther down Perrysville Avenue) and then persuaded the industrial titans of the day to finance the current building.

Brashear was famous, from the 1880s until his death in 1920, for the fine lenses and telescopes he built at his workshop nearby. His optics were used in observatories worldwide. He made two of the telescopes still in use at Allegheny Observatory, and he built the super-precise optics used in revolutionary experiments (by other scientists) that helped physicists understand the speed of light.

His Thaw Telescope, named for one of the main backers of his and Langley's work, gained fame for its precision, as it was used for many years to accurately chart the distance of stars. More recently, it, too, has been used in the search for planets around other stars and is currently being refurbished.

Langley's work was carried out largely at the observatory's original building, but he firmly established the reputation of the Allegheny Observatory in the scientific world. He did pioneering work in the developing science of astrophysics, where astronomers moved beyond just charting stars to using spectroscopy to learn what they are made of. Using the stars to precisely measure time, he helped develop in 1883 the standard time system and zones that we use in the United States and Canada today.

He also was a pioneer in aviation and later built the world's first heavier-than-air aircraft — the first machines that ever flew. He tested wing shapes on an apparatus on the observatory lawn and published an 1891 textbook on mechanical flight that guided subsequent efforts to build the first airplanes. He was bested in the end by the Wright Brothers, who were the first to fly a machine with a man aboard. But they, it is well known, had read his book.

Tours of the observatory are conducted from 8 to 10 p.m. Fridays, April through Nov. 1, and 8 to 10 p.m. Saturdays, April through the end of August. The tours are free, but reservations are required. Details: 412-321-2400 or

John Conti is a former news reporter who has written extensively over the years about architecture, planning and historic-preservation issues.

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