First came the telescope, then the observatory itself.The surprising history of Allegheny Observatory in Observatory Hill.

By: Nick Eustis


Walking down the flat Riverview Avenue – a road rarity for Pittsburgh – solitary rows of houses decorate the roadway. The homes and their taciturn stares quietly build anticipation as one comes face-to-face with the rest of an idyllic hill, where a landmark rests.

A trio of domes sits atop Greek columns overseeing the wildlife below and the questions above.

The rich chestnut brown anterior door hides generations of history in plain sight.

This marble marvel is home to the Allegheny Observatory, which has sat at the summit of Observatory Hill in Riverview Park for over 100 years. Dedicated to the University of Pittsburgh in 1912, the Observatory today functions as a ground for Pitt’s undergraduate astronomy researchers. In addition, the Observatory holds regular attractions for the public, including tours, lecture series, and open house events.

However, public outreach has not always been the main focus of the Observatory. According to current director David Turnshek, the Observatory once functioned primarily as a research laboratory, public events were secondary.

“The Observatory in 2018 is a lot different than it was in the early 1900s. I would say circa the mid-2000s, that’s when the research being done at Allegheny Observatory declined,” said Turnshek.

While scientific research would drive the Observatory through much of its 100-plus years, it was not why the Observatory came to be. In 1858, the notable “Donati’s Comet” was visible across the world, sparking a renaissance of excitement surrounding space and celestial bodies. This wave of interest in astronomy would inspire five of Pittsburgh’s wealthiest patriarchs to create the Allegheny Telescope Association (ATA) in 1859. This began the first phase in the Allegheny Observatory history; one decidedly not rooted in science according to Observatory historian and tour guide, Arthur Glaser.

“That phase of the Observatory’s history is one of a gentleman’s club, not a research institution,” Glaser said.

After acquiring a 13-inch telescope from Henry Fitz, the ATA needed to build a suitable space to house it. This would result in the construction of the first Allegheny Observatory on Perrysville Avenue in 1860, much closer to downtown Pittsburgh than the current observatory in Riverview Park. Just seven years later, however, the ATA would find itself in an unsustainable situation.

Allegheny Observatory now sits atop the entrance to Riverview Park in Observatory Hill. Photo credit: Neil Strebig

“The interest in the club began to wane. Members were dropping off, dues weren’t being paid. So Mr. William Thaw, who was the chairman of the board of trustees, suggested that [they] liquidate the Allegheny Telescope Association,” Glaser said.

Unable to sell their assets, the decision was made to donate the observatory to the Western University of Pennsylvania, known now as the University of Pittsburgh, in 1867.

That same year, the University recruited mathematics professor and astronomer Samuel Pierpont Langley from the US Naval Academy in Maryland. Langley’s tenure as director marks the start of the second phase in the Observatory’s history.

It was under Langley’s tenure that research would become the primary mission of the Observatory. He would use the Observatory to study the sun, particularly the sun’s temperature, and sunspots according to Observatory manager of operations Louis Coban

Langley would also establish a source of steady income for the Observatory that would have implications well outside the realm of science. Using the Observatory’s measuring equipment, Langley would calculate the exact time of day based on the location of stars, then sell that information on a subscription model via telegram. He began this time service in 1869.

This system became particularly influential when the Pennsylvania Railroad decided to run its train schedules on “Allegheny time.”

“With the benefit of the telegraph, you can put the railroad on the same time in Philadelphia, New York, and Pittsburgh,” said Glaser. “Every station along the line can be at the same time, which was unheard of [at the time].”

This innovation resulted in the creation of railroad time zones, a precursor to our modern system of time zones.

“Langley is not an inventor of [time zones], but the kind of work he did for the railroads is a contributing factor,” Glaser said.

According to Coban, Langley would continue to direct the Observatory until his departure for the Smithsonian Institution in 1891. His assistant, James Keeler, would take over the director position.

At this time, Pittsburgh’s heavy industrial pollution began to make the Observatory difficult to use, so Keeler decided it was time to move further from the city.

According to Glaser Keeler was fielding multiple offers from other observatories and research labs, however, he opted to stay in Pittsburgh under the circumstance that a new observatory be built.

“When all this is going on, there’s some bad economic times. So getting the money and getting it started on Keeler’s timetable didn’t happen,” Glaser said.

Keeler would ultimately take a position at the Lick Observatory on the West Coast in 1898 before ground was broken on the new Allegheny Observatory. Subsequent directors Frank Wadsworth and Frank Schlesinger would oversee the construction of the Observatory that stands today in Riverview Park. Its completion in 1912 began the third phase in Allegheny Observatory history.

Director Schlesinger would ultimately solidify the areas of research that the Observatory would focus on. According to Arthur Glaser, the Observatory’s large refractor would be used to study the distances of stars from Earth.

“Our 30-inch reflector will be used to study binary stars, [and] multiple star systems,” Glaser said.

This would be the basic direction of the Observatory for the nine decades. There would be variations in the topics of research over time. Director Heber Curtis, who headed the observatory from 1920 to 1930, would use the observatory to study galaxies outside our own. The more recent director George Gatewood studied extra solar planets including the existence of planets around the red dwarf star, Lalande 21185.

It was upon Gatewood’s retirement in 2008, however, that the Observatory began to change. According to Turnshek, up until 2000, the Allegheny Observatory was the leader in for measuring astrometric parallaxes – or measuring the distance between stars.

This was in large part due to the success of the Observatory’s main 30-inch Thaw Refractor Telescope. However, the primary role of the Hipparchus satellite, which was launched in 1989, was also the continued study of astrometry (positional astronomy). By the end of the satellite’s research period, many of the findings at Allegheny Observatory conducted by the Thaw Telescope were rendered obsolete.

Outdated technology along with increasing levels of light pollution from the growing city of Pittsburgh created a difficult transition period for the Observatory.

An image of the moon taken by the 30-inch Refractor Telescope. Photo courtesy of Allegheny Observatory.


“In this day of large telescopes on remote mountaintops and space telescopes, it is true that the location of Allegheny Observatory, local light pollution, and local poor weather make it a fact that the 100-plus- year-old Allegheny Observatory will never be the premier astronomical observatory it once was. This is true of any observatory that was built prior to the 1940s,” said Turnshek in an e-mail correspondence.

Following Gatewood’s retirement, David Turnshek took over the director role in 2008, the twelfth in the Observatory’s history. Turnshek, jokingly admits he’s somewhat of a “caretaker” in regards to the historical preservation of the Observatory. However, he’s still earnest when discussing the role the Observatory has an educational resource despite its decrease in astrometry specific research.

The Allegheny Observatory is currently home to the Search for Transiting Exoplanets at the University of Pittsburgh (STEPUP) program. STEPUP program consists of approximately 7 undergraduate students, whom study using the planetary transit method to obverse exoplanents, or “a planet orbiting a star outside the solar system,” according to Turnshek.

“Currently the research we do at Allegheny Observatory involves verifications of the existence of exoplanets using the planetary transit method,” said Turnshek. “Research continues, but there is now more emphasis on educational classes and public outreach.”

Still, more than a century later, behind those humble chestnut doors – a testament to the deep roots of Pittsburgh institutions – rests a memorial to the men and women who so strongly believed in the virtues of truth and discovery.



This article was last updated to on Sunday, February 4 at 10:15 a.m.*

*A previous version of this article stated that the STEPUP program consisted of approximately 15 Ph.D. students and 20 graduate students. However those 35 students are part of the University of Pittsburgh’s Department of Physics and Astronomy, none of which are currently doing department research out of the Allegheny Observatory. In addition “astronomic wobble” was identified as the research method of choice for STEPUP students, that was incorrect.