 I stomp on my car’s brake pedal, sending it sliding to a quick stop on the narrow, dusty road. Emerging from a blind curve, the driver of a Jeep bearing government license plates does the same. To my left is a wall of sheer rock; on my right the road drops precipitously out of sight. The other driver and I stare at each other through the resulting dust cloud like gunslingers in an Old West showdown.
This is the only route to the MMT Observatory, a massive telescope perched at the top of Mount Hopkins in Southern Arizona’s Santa Rita Mountains east of Green Valley. I’m traveling to the 8,500-foot peak to get a first-hand look at modern astronomy. While I know that professional astronomers no longer spend the night squinting through an eyepiece, I’m eager to learn how the whole process works.
Up the mountain
As the standoff continues, I blink first, shifting gently into reverse before creeping backward out of the sharp turn. I inch over to the road’s edge just enough for the Jeep to squeeze by. The driver doesn’t acknowledge me, but two children in the back look at me with blank expressions as they pass.
I glance down at the radio given to me by the MMT staff back at the University of Arizona. Drivers are supposed to warn one another as they travel up and down the mountain, but it’s a public road until a locked gate near the observatory.
After a few more miles, I find a crude scenic overlook and stop to take photographs of the breathtaking view. The surrounding mountains look soft and velvety with their cover of tan grass and green creosote bushes. They fold gently toward the horizon as I gaze south into Mexico.
Another car soon joins me. It’s Edward Olszewski, the astronomer from the University’s Steward Observatory who will be showing me around the MMT. We comment on the view, and Ed reminds me not to stop for hitchhikers when I leave this evening. These mountains are a popular route for drug smugglers and migrants crossing from Mexico into Arizona.
I follow Ed’s car the remainder of the way to the MMT. We stop at the mountain’s ridge for a tour of the dorms, where visiting astronomers sleep during the day. The accommodations are cozy, with a kitchen, living room, television and billiards table. Pine trees give the building a mountain cottage effect that feels worlds away from Arizona. There’s also a library with a vaulted ceiling to accommodate towering shelves of astronomical journals that probably haven’t been opened in years. The real research gets done on a Mac with large dual screens sitting in the center of the room.
On top of the world
A few days earlier, I asked Richard Cool, an MMT staff scientist, about the observatory’s strange name. He said that when the telescope was built in 1979, engineers hadn’t quite perfected the construction of huge pieces of telescopic glass. The Multiple Mirror Telescope, as it was originally called, had six 1.8-meter mirrors arranged in a hexagon that equaled the power of a 4.5-meter telescope. Technology evolved, Cool said, and in 2000 the MMT was upgraded to a single 6.5-meter mirror.
But old habits die hard. The MMT acronym turned into a name, and it still stands.
The telescope itself is bolted inside a nondescript four-story box. The observatory uses an altitude-azimuth design, which means it tracks celestial objects by moving on two axes: vertical (altitude) and horizontal (azimuth). The telescope itself, however, only swivels on the altitude axis. For azimuth, the whole building rotates.
This is my first discussion topic with Alejandra Milone, tonight’s telescope operator. Astronomers don’t get to push many buttons at the MMT. That’s Alejandra’s job. When she commands the building to rotate to tonight’s first target, I hardly feel it moving. Only a smooth, faint whine reveals that anything is happening. It becomes much more apparent that the building has turned when I exit the observatory and realize I’ve been deposited in a completely different spot from where I entered.
The right robot
There’s no eyepiece under the MMT’s massive mirror. Instead, several instruments can be attached to the bottom, depending on astronomers’ research needs.
Tonight, Ed is using a spectrograph, which takes starlight and splits it into component wavelengths the way a prism splits white light into a rainbow. Star spectra can reveal myriad details to astronomers, and tonight Ed will be using them to measure how fast stars in a nearby dwarf galaxy are moving. Dwarf galaxies are much smaller and contain fewer stars than our Milky Way.
Ed’s stars are so faint that Alejandra will need to keep the telescope trained on them for 20 minutes to produce a single spectrum. If the team could image only one star at a time, it would take forever to conduct this type of research.
Enter two dancing robots named Fred and Ginger, and a robot operator named Mike Calkins. Mike is a physical scientist for the Smithsonian Institution, which jointly operates the MMT with the University of Arizona. Under the mirror is a ring of tiny fiber-optic cables that sends starlight to a nearby room where the spectrograph resides.
Mike offers to give me a peek while he reconfigures the delicate, dust-averse spectrograph, but not before I don a hair net and beard cover. When I point to a large lens while asking a question, the easygoing scientist politely asks me to keep my hands to myself.
Under Mike’s control, Fred and Ginger deftly arrange several dozen fiber-optic cables to match the map of a star field. As we watch the robots’ progress on a monitor in the observatory’s control room, Ed remarks that the placement of the cables must be accurate within the width of a human hair.
One of the last steps before starting the 20-minute exposure is aligning Fred and Ginger with guide stars, which allows the telescope to move precisely with the Earth’s rotation. But there’s a problem. One of the guide cameras isn’t working properly, so Mike can’t see to align the instrument.
After a few phone calls for troubleshooting, he improvises by eyeballing the guide stars with another camera. He starts the exposure.
It’s a tense 20 minutes. If the resulting spectra are unusable, Ed may be out of luck. Astronomers apply for telescope time months in advance, and cloudy skies or faulty instruments can ruin their night.
Fortunately for Ed, that doesn’t happen. After a computer screen fills with a telltale array of gray-scale lines, Mike’s estimation appears to have been dead-on. Further analysis will be required later, but for now, the data look good.
Back to reality
As I creep back down the mountain under moonlight, I feel fortunate to have been present at the MMT for a glitch. Judging from the reactions of Alejandra, Ed and Mike, problems don’t happen often. A repair team will head to the observatory tomorrow in daylight to help Mike figure out what happened to the camera. It dawns on me that Mike might have to work through his night — my day — to ensure that the telescope is ready for operation when the sun sets tomorrow.
For Ed, actual observing time constitutes a small part of his astronomy career. He’ll return to the real world after just two nights. There’s teaching and research to be tackled, not to mention the pile of data he will have collected.
But it’s much different for telescope operators. Mike, for instance, alternates three weeks on and off the mountain. He says it puts a major strain on maintaining a relationship, and he often can’t sleep when he comes back to civilization.
Just then, a ringtail — Arizona’s state mammal — darts into my headlights before disappearing just as quickly. Ed told me a story about a family of ringtails that was determined to make the MMT their home despite being chased out several times.
While all this seems exciting to me, I recall Alejandra saying she likes her nights to be boring. It’s hard to believe that’s even possible, but visitors to the MMT are really just passing through someone else’s world.
Editor's note: Mike Calkins was misidentified in an earlier posting of this story.