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Hidden in Plain Sight: Detroit Observatory In Ann Arbor

Jul 9, 2018

Atop a small hill at the corner of Observatory and East Ann Streets in Ann Arbor sits a facility operated by the University of Michigan’s Bentley Historical Library.  It’s been at that same location for over a century now.  Still, as 89-1 WEMU’s Jorge Avellan reports, the Detroit Observatory has remained largely “Hidden in Plain Sight.”  


"In the 1850’s, if you wanted to be a research university, you had to have an observatory."

With that aspiration, the University of Michigan opened the Detroit Observatory in 1854.  It was the first observatory built anywhere in the state of Michigan.  Karen Wight serves as the observatory’s project coordinator and historian.  She says the first thing you’ll notice is some of the facility’s Greek Revival architecture.

Karen: When you first walk in the doors you’re seeing the large arches that support the dome on the second floor.  And then through the arches you see an even larger telescope pier which is essentially one brick patio on top of another brick patio from 15 ft. below grade to up underneath the telescope. 

Jorge: It kind of looks like a silo. 

Karen: It does

The pier is tightly surrounded by seven Oakwood display cases that contain early astronomy books and other historic artifacts.  As we stand shoulder-to-shoulder, Wight points out an interesting feature on the floor.

"These are all fir floors, soft wood.  But you will notice that it does not touch the pier, the building is actually built around the pier and that is to isolate the telescope and damp it from vibration.  So that if there is any vibration in the building like stomping around the wood floors…that’s not going to travel up the pier.  And the vibration that they were even more worried about in the 19th Century was from railroad trains.  A railroad use to pass a lot closer to this building in the 1850’s," said Wight.

A few steps from the pier is a small area called the transit room.  Your eyes are instantly drawn to the eight-foot long brass telescope that’s mounted on two brass wheels.  It’s known as a Meridian Circle, and this one looks like a cannon on wheels.  University of Michigan astrophysicist Mike Roman explains. 

"If you noticed it’s aligned so it can only really tilt up and down, it doesn’t go left or right.  And that’s because it’s already been carefully placed on these piers, these piers that extend well below the surface of the Earth, to keep them very stable.  It’s resting on those and aligned so it can watch stars as they pass through this slit in the building, which is aligned North-South in the sky," said Roman.

I didn’t really know what slit Roman was referring to until he walked over to a nearby crank.

Mike: Right now I’m just opening the Meridian transit slits in the transit room.  It’s just a matter of cranking this, basically like a large grandfather clock key or crank.  And it’s pulling open these long transit doors. 

Jorge:  And now there is an opening in the center of the roof, essentially. 

Mike:  Yeah, and now one can observe overhead across the sky, North-South.  And there are also these doors on the side that allow you to observe all the way down to the horizon, in theory, if you open all of these up

But the fun doesn’t end there.  We then make our way up the stairs to the second floor.  Historian Karen Wight pulls out a key to open a narrow doorway-entry.

Karen: So, we have about 22 inches here.  And then you step up and you’re in the dome. 

Jorge:  That’s pretty cool. 

Karen:  It is a very wonderful dome.  We just recently had it rebuilt because there was a fair bit of water damage, and the university did a fantastic job restoring it.  So it's two layers of materials over the vertical joist.  There are tin shingles outside and a canvass lining inside, and then we essentially have a tiny garage door that you need to open up and move aside so that the telescope can look out of the dome because we do not have an X-Ray telescope.

University of Michigan astronomer Shannon Murphy has joined us.  She’s been given the task of opening the dome’s shutter.  It measures 20 feet long by 16 inches wide.

Shannon: There are two big weights that hang down from shutter, and I’m grabbing the one that is the shorter one, and I will see if I can get it open by basically jumping up in the air and falling.

Jorge: You got it.  You got it open.

The hot sun shines on our faces as we look up at the blue sky.  Wight then tells me it’s my turn to have some fun.

Karen: The rope that you see embedded in the wall over there. 

Jorge:  The very thick rope? 

Karen:  Yeah, the very thick rope, you pull on it.  You can’t hurt anything.  And you will be able to move the dome. 

Jorge:  Is it going to hurt me?  I’m just joking….Oh, so it’s rotating.  The dome is rotating as I’m pulling this very thick rope. 

Karen:  And would you say it’s difficult for you to do that? 

Jorge: It’s not bad.  No, I’m just using one hand because I’m holding the microphone in the other.  But it lets me know that I need to be in better shape…but other than that, it’s not bad at all. 

Karen: This was not a one-person operation.  In fact, it’s not a one-person operation now which is why we have a crew of telescope volunteers to operate the telescope.

Astrophysicist Mike Roman says the 17.5 ft. long Victorian telescope was the third largest refractor in the world when it was installed in 1857. 

Roman explains the wonders you can see through the telescope.

"We we’re looking at Jupiter last week, and you can see some of Jupiter’s moons, four of them as they go around the planet.  You can see Saturn and its rings, you can see some of Saturn’s moons.  You can see craters on the moon, our moon, quite easily," said Roman.

Astronomer Shannon Murphy says that former observatory director James Craig Watson made some pretty interesting discoveries at this facility in the 1800’s.

"Watson discovered 23 unique asteroids himself and another couple dozen that he was not the sole discoverer of.  One of his claims to fame was discovering the hundredth known planet.  Of course, it was an asteroid that he discovered, but it was the hundredth known planet at the time which is why astronomers had an argument over what they should call a planet and then classified a group of things as asteroids instead of planets," said Murphy.

The name of that asteroid was Hekate, and it was discovered in 1868.  And talking about names, you may be wondering why it’s called the Detroit Observatory?  Wight explains.

"Henry Walker was a prominent lawyer in Detroit, and when he heard Henry Phillip Tappan give the inaugural address, when Tappan became president of the university, he said he wanted to help the president however he could.  What would be helpful?  And Tappan said, if you can help me raise money for an observatory, and so he did.  And so that’s why it’s called the Detroit Observatory.  It’s because most of the folks that initially contributed funds were friends of Henry Walker in Detroit," said Wight.

While the Detroit Observatory is no longer used for research, it is used for community outreach, viewing nights are held for the public throughout the year.  And who knows, you may even discover a new planet or asteroid that’s “Hidden in Plain Sight.”

For information on viewing nights, click here.  Keep in mind that tickets (free) are needed to enter the main dome area.  You can pick those up when you attend a viewing night. 

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— Jorge Avellan is a reporter for 89.1 WEMU News. Contact him at 734.487.3363 or email him javellan@emich.edu