Mar 102016
Rothney Cross Telescope

The Rothney Astrophysical Observatory is located just southwest of Calgary near the tiny community of Priddis. Owned and operated by the University of Calgary, it’s used as both a research and teaching facility and is home to a collection of telescopes of many forms, types and sizes. We’ll spend a day and night there watching what goes on (and no doubt being a nuisance in the process), documenting the experience, learning a little here and there, and sharing it all with you.

This facility was founded in the early 1970s and is built atop land donated by prominent local rancher, AR (Sandy) Cross. The name Rothney belonged to his mother (her maiden name). His farm was also called the same. Sitting atop a knoll, directly north (well a bit more northeast really – still it’s close) is the sprawling city of Calgary, and cause of much light pollution, to the west, the majestic Rockies, the south, gently rolling hills, and east, the vast Alberta plains. This location assures the observatory a near unobstructed view of the sky come dark. It’s not a bad view, out the front door, during the day either.

Rothney Astrophysical Observatory: the stars, the galaxies, the universe. Written & photographed by Chris Doering, assisted by Connie Biggart.

There are three structures at the facility built at various times. The main one houses two telescopes, one an absolute monster, much control equipment and workshops and offices. The second, the original structure here, houses one telescope and a small office.

The third building is used for classes and acts as an interpretative centre – the “moon” hanging from the ceiling came in from the old Calgary Planetarium. It’s the newest structure here and is about a decade old. This is usually the only area where outside visitors are allowed and even then only on special days, during open houses or by other arrangement. The rest of the facility is typically off limits. All that sensitive equipment, all those controls, there’s too much potential for trouble. One button pushed by mistake, one cord tripped over or ripped out of its socket and it’d be a nightmare.

Rothney Observatory

At the Rothney Observatory near Calgary.

There are three optical telescopes at the Rothney Observatory, all incredible pieces of precision machinery built to extremely tight tolerances. Each is somewhat specialized in its function.

The first installed and the smallest is known as the the Clark-Milone, named after two people highly important to the observatory in the early days, both founding astronomers and together the original co-directors. The dome which it’s housed and a small attached office (done up with 1970s rec-room wood-panelled walls) at the beginning, made up the entire facility here. This telescope can be remotely controlled off-site allowing labs to held back the university. It’s also rented out to other learning institutions. An old rotary phone, no doubt installed when the facility was new, is still in use and hangs on the wall. A bank of desktop computers runs the show.

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The main building was constructed in the 1980s. Inside is the Baker-Nunn telescope, named after the firm that manufactured it. This one is the oldest of the bunch, dating from the late 1950s, that once scanned the skies not for stars and the like, but enemy satellites, Prior to coming here, it was housed at the Canadian Forces Base Cold Lake (Alberta). With changes in technology it was no longer needed and in the early 1980s was donated to the Rothney Observatory.

This telescope is similar in size to the Clark-Milone but was near impossible to shoot given how small a space it’s housed in (this was ongoing problem for the day). The original 1950s era vacuum tube control panel sits in a room below, but is no longer use. The Baker-Nunn is now run by computer. Old and new technology working together.

At the opposite end of the building is the big boy and the newest one here, dating from the latter half of the 1980s, the AR Cross or Sandy Cross Telescope (or simply ARCT). Housed in a giant dome it’s one of the largest telescopes in all of Canada. When any of the machinery is in motion the earth trembles. It’s all huge! So much so in fact, that it was impossible to photograph in the dome’s tight quarters without cutting off parts. No matter how wide-angle the lens, it wouldn’t quite work.

Off to the side is a NASA-looking control room. Some of the equipment seen is designed specifically to control telescopes, some is modified from other uses, while others bits still are pure home brew.

All the telescopes are open to the air when in use so no matter the time of the year, the inside temperature is the same as outside. Not so much a problem in summer, the machinery had to be specially adapted to handle the challenging environment that is a Canadian winter. Staff, students and visitors have to dress appropriately for the conditions as well.

Also in the this same building are workshops. Telescopes require a great deal of upkeep and so repairs, upgrades and general maintenance is always ongoing. A lunch room and offices round out the main floor. In the basement are controls for the Radio Telescope – it’s that huge dish (does it get HBO?) and is set up to scan the skies a bit differently, in search of radio noise instead of visible light sources. As such it can be used in daylight. It points true south, scanning the heavens, what ever heavens come into view as the world spins, only in the direction.

There are many additional telescopes at the observatory, all hobby or enthusiast style ones, put on display or used by students and visitors. There is a special pad where these get set up.

We were given permission to shadow Rothney staff. During the day we spend time hanging with Jim Pake, the technician. His project this day was a shutter sensor and we watched with great interest as he built most of the pieces needed to make it work and then installed and tested them. Rumble, rumble…door open; rumble rumble, door close. Then do it again and again. Quick with a joke, and a great impressionist (what a “radio” voice)’ he knows the inner workings of everything here down to the last nut and bolt.

Rothney Observatory Calgary

With nightfall the real fun begins.

Jim refers to telescopes as “light buckets” and makes mention of the light pollution problem they’re having here as Calgary encroaches on the observatory lands. When a telescope is facing a certain direction (north or north-ish) the glow of the city can cause viewing problems.

For the night shift we’re greeted by Jennifer Howse, who oversees day to day operations and is the only real staff member that’s stationed at the observatory all the time. Most of the others commute, coming in from the main university campus only as needed.

Phil Langill, director of the facility, arrives on the scene. The observatory this night will host a group of Boy Scouts and later, a large party of students from the U of C and he’s the master of ceremonies, showing them all around and demonstrating how things work. We were of course were a “fly on the wall” to this action. The students are given the chance at the AR Cross eyepiece – we get to take a look as well. The stars, the galaxies, it’s wonderful! I wish I could have someone captured a photo. I wonder…what if we duct-taped the camera to the eyepiece? Oh…never mind.

An unexpected visitor this night were the auroras. Normally they’re not easily seen so close to the city (that dreaded light pollution) but we’re happy they showed. What a great photo-op. The stars are out, the auroras are out, it’s pure magic. Interesting note: even in today’s high tech age, nature alone determines if and when the telescopes are to be used or not. An overly cloudy sky, and goodness that’s not that usual, and everything’s cancelled. Observatory staff must keep a close eye on the weather.

And before we know it, we’re done. In the twelve or so hours spent at the facility we’ve learned so much (yet at the same time, barely touched on things) which I hope translated well for our readers. What an interesting place!

The general public can drop by the venue at select times. For more information, here’s their website…
Rothney Astrophysical Observatory

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If you wish more information on what you’ve seen here, by all means contact us!

Date: February, 2016.
Location: Priddis, AB.
Article references and thanks: Rothney Astrophysical Observatory, AR (Sandy) Cross archives. Phil Langill, Jim Pake, Jennifer Howse., of course, was on site with permission.

Rothney Astrophysical Observatory

Hallowed halls – the old phone is still used!

Circuit board

Inside the workshop, a random circuit board.


Observatory machinery is maintenance intensive – a sensor is worked on.

Telescope eyepiece

Tiny eyepiece on a huge telescope – most viewing is by monitor however.

Rothney Calgary

Inside the classroom – the moon came from the old Calgary Planetarium.

Calgary Rothney Observatory

The big dome houses one of the largest telescopes in Canada.

Radio telescope

The Radio Telescope.

Rotary wall phone

Another still-in-use rotary phone.

Clark-Milone Telescope

The smallest telescope here, the Clark-Milone.

RAO Clark-Milone Telescope

It was the first telescope at the site.

RAO Calgary class room

The classroom building.

Space walker

Space walker.

AR Cross Rothney

Jim Pake keeps the machinery running.

AR Cross Telescope

Part of of the huge AR Cross Telescope can be seen to the right.

AR Cross Rothney

Testing the shutter mechanism.

AR Cross Rothney Calgary

The telescope is so large, even with a wide angle lens it’s hard to get it all in.

Baker-Nunn Rothney

Cold war era control equipment that once ran the Baker-Nunn Telescope.

Rothney Observatory classes

A small telescope set up for students.

Telescope controls

The main control panel.

Rothney Radio Telescope

The auroras make an appearance.

Rothney Cross Telescope

The AR Cross Telescope is readied for action.

Telescope control panel

The open dome lets in the cold – Phil Langill at the controls.

Cross Telescope Rothney Observatory

Drop the lights and the stars come out to play…


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12 Comments on "Rothney Astrophysical Observatory"

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Barb Watts
Barb Watts

Thanks for sharing your incredible photographs.


Amazing photos, I so want to go there!

Gail Higgens
Gail Higgens

Outstanding work Chris and Connie!

Becky McNabb
Becky McNabb

Long time lurker. Beautiful, stunning, breathtaking! Great write up and amazing photos. The last ones totally blew my mind.

Barry H
Barry H

Man, your work is really good!!


Thank you for sharing your incredible adventures and those amazing photos.