Dearborn Observatory: Linked to the Stars
Chants filled the air as hundreds of students lined the streets. The procession marched from Hinman to Church to Davis. Trumpets and horns blasted along the way to the buzz of cheery voices intermingling. It was a time of celebration: college chants and presidential speeches and wild bonfires to cap off the end of the night.
Among the crowd, one could catch glimpses of various inscriptions.
“NWU linked to the stars,” one of them read. Another sign, cut in the shape of a large telescope, declared proudly, “Our telescope.”
It’s early November in 1887, and Northwestern’s long journey with astronomy has just begun – with the acquisition of the historic Dearborn telescope.
Dearborn Observatory standing still in the spring of 1939.
Credit: Northwestern Alumni News, Volume 19
Just as Wildcats decades ago used to peer through the telescope’s lens and observe the wide night skies, hundreds of visitors and students can do the same now. The only thing separating them is a century of discoveries, expansions, and challenges overcome.
Credits: NU Archives
Dearborn Observatory’s Early Days
The prized telescope sitting beneath Dearborn’s dome dates back to the Civil War era. It was made by optics crafters Alvan Clark and Sons in 1861, who were responsible for manufacturing some of the largest refracting telescopes at the time. Though it was originally meant to go to the University of Mississippi, the outbreak of war disrupted the impending transaction.
Yet, even as the lens idled in the Clarks’ workshop, it remained full of potential for discovery. In fact, the 18.5 inch refractor found the long-predicted, but never before glimpsed, companion star to Sirius in the sky – thanks to the younger son Alvan Graham Clark, who tested it one January night in 1862.
At the time, this instrument was the largest telescope in the world.
G.W. Hough, Dearborn’s fifth director, stands before the Gurnee Meridian Circle.
Credit: NU Archives
The telescope’s connection to Chicago began with the Chicago Astronomical Society (CAS), a group of volunteer Chicagoans who came together in 1862 aiming to push the Windy City into the forefront of astronomical expansion. This, of course, required getting a telescope and observatory.
That year, CAS learned of the Clark telescope’s existence. How they got it was all thanks to serendipitous timing: An agent named Thomas Hoyne visited the Clarks’ home in Boston, only to find Clark Sr. had already left to negotiate terms with the Harvard Observatory director. Immediately, Hoyne made the offer to buy the lens for Chicago, ultimately purchasing it for $11,187 (the equivalent of almost $300,000 today).
The first home of the telescope was the old University of Chicago, in a building funded by benefactor J. Young Scammon, who named it after his late wife Mary Ann Haven Dearborn. The observatory featured a large tower, protruding above an otherwise medieval-looking structure, that held the 18.5 inch lens, as well as room for an additional telescope, the Gurnee Meridian Circle.
Chicago Dearborn found its answer in something unexpected: timekeeping.
For a while, the observatory was in charge of maintaining public time for the city, on top of astronomical studies. However, the Great Chicago Fire in October 1871 ceased many of these operations and wiped much of CAS’ records. This, alongside the ensuing Panic of 1873, was a major setback landing Dearborn in financial straits.
Yet, through the efforts of an amateur astronomer named S. W. Burnham – who began his mission to catalog the sky’s double stars with a small telescope in his own backyard – Dearborn Observatory was revived once more.
As Burnham continued to grow in fame as an observer, so did the observatory. In fact, Burnham discovered his 188th companion star using Dearborn’s telescope, three days before Christmas in 1873. He, according to Dearborn’s fifth director – G. W. Hough – discovered a greater number of first-class double stars than any modern astronomer of that era.
Curious to Learn More About Dearborn Observatory's Chicago Days?
“The Dearborn Observatory, located on the Old University of Chicago campus from 1863 until 1888, was America’s most promising astronomical facility when it was founded. Established by the Chicago Astronomical Society and directed by one of the country’s most gifted astronomers, it boasted the largest telescope in the world and virtually unlimited operating funds. The Great Chicago Fire of 1871 destroyed its funding and demolished its research programme. Only via the sale of time signals and the heroic efforts of two amateur astronomers did the Dearborn Observatory survive.”
Ian R. Bartky, “Chicago’s Dearborn Observatory: a study in survival” in the Journal of Astronomical History and Heritage
G. W. Hough (far left) and S.W. Burnham (far right) sit outside the Dearborn Observatory.
Credit: AIP Emilio Segrè Visual Archives
Hough, appointed to his position in 1879, was Northwestern’s first connection with Dearborn Observatory. Nicknamed “Jupiter” Hough for his fascination with physical phenomena upon said planet, he was also dedicated to studying double stars, comets, and planets and satellites.
Hough’s directorship oversaw another tumultuous time for the observatory. The eventual adoption of Standard Railway Time (which paved the way for America’s actual time zones) left Dearborn’s previous income source irrelevant. The old University of Chicago suffered financially as well, falling into debt and eventually declaring bankruptcy in 1886.
With the threat of foreclosure imminent, the pressing question arose: What will become of Dearborn’s telescope?
Students and Northwestern staff highly anticipated the move, enthusiasm brewing over the newfound connection between the university and a renowned instrument. As students took to the streets in November 1887 to celebrate their new telescope’s homecoming, they were keenly aware, even then, that Northwestern’s path to the stars was just beginning.
Northwestern Sees the Stars
Dearborn Observatory in its original location.
Credit: Evanston Photographic Service
After its official dedication in 1889, the facility bloomed with astronomical research. Hough, who became Northwestern’s first professor of astronomy, found several hundred new double stars with the Dearborn telescope, the study of which laid a crucial foundation for determining stellar masses and understanding gravity – more broadly, the fabric of the universe. He also invented the observatory’s revolving dome, allowing for the observation of planets in all directions and degrees.
Believe it or not, our lake used to extend much further into campus than it does now. And even more unbelievably, Dearborn Observatory used to stand where the waters once lapped right up to the back of the building!
Hough’s successor Philip Fox, who later took over in 1909, continued the observatory’s longtime observations of double stars, making thousands of observations which were published under the Annals of Dearborn Observatory. Following his time at Northwestern, Fox would later become a director of the Adler Planetarium.
During his directorship, Fox modernized much of Dearborn’s instruments, including the updated mounting and driving gear for the telescope – which replaced its original Clark mounting in 1913. (The original piece can be found at the Adler in Chicago.)
Fox also designed and built a stellar spectrograph, which made over 1,800 spectrograms of bright stars following the end of WWI.
Throughout the rest of the 20th Century, Dearborn Observatory participated in various other research efforts: measuring continental drift, photographing passing asteroids and comets, classifying all the faint red stars in the northern heavens (a project led by the observatory’s eighth director, Oliver J. Lee).
The original mounting for the Dearborn telescope is still on display at the Adler Planetarium today.
Credit: via a paper by Craig Deller, “The Conservation of the Historic Dearborn Telescope”
As the Space Age took off in the 60s, sweeping the rest of the nation along with it, Dearborn also buzzed with activity. The installation of a pioneering technology, known as an image orthicon system, granted the observatory the ability to take what were, at the time, the clearest images possible of the cosmos and project them onto a television screen. This way, students could view the lunar surface and skies, including ambitious missions to send astronauts to the moon, from the comfort of campus.
But before even that, in 1914, the American Astronomical Society held its 17th annual meeting on Northwestern’s own campus. Just outside of the quaint brick observatory building stood Edwin Hubble, then a young graduate student. Supposedly, it was this meeting that sowed the seeds for Hubble to eventually discover the ever-present expansion of our universe – a breakthrough of modern astronomy that was inspired by a talk given by Professor Vesto Slipher, that day in Evanston.
Members of the AAS stand outside of Dearborn Observatory for the 17th Annual meeting. Edwin Hubble is in the dark suit in the front row, 2nd from the right.
Credit: AAS
For the last century, Dearborn has also been open to the public for weekly viewing sessions. While astronomy students used the telescope for classes, locals could also gather at the observatory to see snapshots of Saturn’s brilliant rings or Jupiter’s vast Red Spot. A few fortunate Wildcats could even catch a glimpse of once-in-a-lifetime passerbys such as Halley’s Comet.
Under the direction of Oliver J. Lee, observatory director and department chairman, Dearborn was raised three feet, placed on rollers, and pulled about 600 feet southeast.
Credit: Northwestern Alumni News, Volume 19
Dearborn’s next major move wasn’t across state or city borders, but rather across campus. In the summer of 1939, in order to build the Technological Institute, Northwestern needed to shift the observatory about 600 feet southeast to its current location – a feat made possible thanks to literal horsepower and about 700 jacks!
Moving Into the New Millennium
Dearborn’s role as a research facility lessened with the construction of a brand new building on campus – which many alumni will remember as the Lindheimer Astronomical Research Center (LARC).
During the 1960s, most of the astronomy action and education for students fell on Lindheimer and another observatory in a remote part of New Mexico, called Corralitos. Unfortunately, factors like poor weather conditions and Chicago’s light pollution wore down on atmospheric seeing conditions, undermining the ability for Wildcats to continue pumping out as much cutting-edge work. Rather, Dearborn became more of a site to house researching astronomers.
As the years have gone by, bigger instruments and facilities have also been built, eclipsing the size of the 18.5 inch, which was once the largest in the world.
Yet, the observatory remained a place for students to explore space on their own time. Robert Lentz, a former physics and astronomy graduate student at Northwestern, recalls how he spent all summer sitting at the steps of the Dearborn telescope to spot the fragments of the comet Shoemaker Levy 9 – which crashed into Jupiter in July 1994, bruising its surface all over.
Dearborn Observatory received a brand new dome in 1997, thanks to Observa-DOME.
Credit: Dearborn Facebook
Ultimately, though, parts of the observatory had fallen into disrepair by the end of the 1990s. The round room under which people could look through the telescope was unfinished. Stray pieces of bird’s nests often fell to the floor whenever the dome opened, according to former NU astronomer Diane Dutkevitch, who oversaw Dearborn’s eventual renovation.
When the decision was made to dismantle the Lindheimer building at the end of the century, the astronomy department’s next and most urgent step was to find a suitable replacement observatory for students. Classes needed a usable telescope for education purposes, and moreover, the surrounding community also needed access to a telescope for public viewing.
Thus, university administration helped fund Dearborn’s rehabilitation.
The drive system was upgraded to be computer-controlled. The telescope was painted purple instead of battleship gray. The old rickety dome was replaced with a shiny new construction by Observa-DOME – who, being from Mississippi, were excited to see what had become of their “Ole Miss” lens.
“They made it clear Mississippi has not forgotten! That was a hoot.”
This renovation, completed in 1998, was the last major upgrade to the observatory. Astronomy students could once again use the telescope for regular observations, and the public regained access to the observatory the year after.
Now, when entering the building, you’d be surrounded with wood and brass washed in a glowing red light. You’d see a long tube sat atop large, rolling stairs. And when you follow that tube upward, you will see a slit in the dome where the telescope can peer through the atmosphere.
Dearborn’s current and fourteenth director, Michael Smutko, calls it a state-of-the-art public outreach facility. It reaches thousands of visitors a year, with up to one or two hundred coming in for viewing sessions on clear Friday nights.
Northwestern is one of the few campuses in the country with access to its own historical observatory (that’s still in operation!), allowing students and the surrounding community prime access to the cosmos – without needing to book additional telescope time elsewhere.
Workers lower the newly painted telescope mount.
Credit: Dearborn Facebook
“We have a world class outreach facility in Dearborn. We can offer things that only a handful of universities can offer. We’re very proud of that, and absolutely want to keep doing it as long as we possibly can.”
The telescope, the beating heart of Dearborn, has moved across states, cities, and even our own campus on the backs of donkeys and horses and rollers. It has survived many struggles and witnessed the steady growth of astronomy on campus – even took part in it, at times.
When one walks into Dearborn Observatory now and peers up through the old Clark telescope, which was the first to seek out Sirius B’s once-invisible companion star, they can know they are holding history in their hands, a story spanning almost a century and a half.
Astro Science Workshop students using the Dearborn telescope.
Credit: Dearborn Facebook