Venus Transit Retro-Blog: Visiting CFHT

2012 June 07 – The Sky and Telescope Venus Transit Tour was over. A small sub-group was heading out to visit the Imiloa Astronomy Center, but most of us were leaving the group. I was staying in Hawaii for a few more days, but shifting myself to Hilo for less expensive accommodations, and better access to Mauna Kea and Volcanoes National Park.

Saddle Road threads between Mauna Kea (left) and Mauna Loa (right). At the midpoint, it tops out at about 6500 feet.

Saddle Road still has an undeservedly bad reputation, and some car rental companies don’t allow renters to use it. It’s been upgraded, though it still has a few one-lane bridges to remind you of its origins as a military road. Even so, Saddle Road is a good way to get across the Big Island. It’s an interesting drive, too.  As you work your way up the shallow (but very long!) grade, you go through several climate zones, and pass over a few old lava fields.  By the half-way point, find yourself at a 6500 foot elevation, preparing to go right back down to sea level.

By the time I’d reached Hawaii, I had tentative arrangements to visit the Canada-France-Hawaii Telescope (CFHT) and Gemini North, two of the three Mauna Kea observatories in which Canada is a partner. (Alas, I wasn’t able to make arrangements to visit the third, the James Clerk Maxwell Telescope.)  My arrangements were reasonably firm, but my visits would be subject to operational concerns, and could have been cancelled. I didn’t get the final confirmations until June 06. In fact, I actually got the confirmation calls while I was on my commercial trip to the summit.

This is the start of the Mauna Kea Access Road. The observatories aren’t visible from this angle.

After checking in at my Hilo hotel, I turned around and went back west on Saddle Road and on to Mauna Kea. I’d be meeting my host at Hale Pohaku, and he’d be taking me from there to the summit.

The drive to the Visitor Information Station was lovely, but a tough enough burden for my rental car. Even with embedded computers to adjust fuel mixture, timing, and such, car engines don’t work efficiently at 9000-odd feet.  The temperature gauge was getting uncomfortably close to the red line by the time I pulled in at the VIS.

On the previous two trips, I hadn’t had much trouble with the altitude, but I took my pulse oximeter along out of curiosity. At the VIS, I took a measurement of 92% oxygen saturation. The previous trips must have improved my acclimatization.

David Woodworth, CFHT remote observer and operator. You couldn’t ask for a more knowledgeable and personable host.

At the staff residence complex, I met my host, David Woodworth. David came to Hawaii years earlier and loved the place on sight. As he put it, “I got to Hawaii and then decided I had to find a way to stay here.” He’s worked at a grade school teaching mathematics, at the University of Hawaii, and then for the CFHT Corporation, starting out as a telescope operator. Automation cut into operator positions, so David upgraded his skills and became a remote observer. In that capacity, he doesn’t have research projects per se, but he handles queued observations and assesses the images he acquires.

David’s also taken an interest in the geology and archaeology of the Big Island. He’s got a lot of background to share, and he’s a natural story-teller. It’s a shame David hasn’t written a book or hosted a documentary.

We met the other members of our observatory tour, a group of French amateur astronomers who’d made arrangements through a French researcher at CFHT. They’d observed the Transit of Venus from Maui, and had just come to the Big Island.  Nicolas, Christian, Pierre, and Serge are members of a group specializing in astronomical drawings, and the examples I’ve seen are exquisite. I’m looking forward to seeing their drawings of the Transit.

We did have a linguistic challenge. My French colleagues spoke little English, and David speaks little French. This left me in an interpreter’s role — a bit of stretch for me. I’m going to claim that I forgot most of my French grammar because of the altitude. (That’s my story, and I’m sticking to it!)  In any case, we all managed with plenty of good will and a more than a few laughs.

The view from CFHT, facing east.

CFHT started operations in 1979. As one of the earliest observatories to be established on Mauna Kea,  CFHT has an enviable location. It’s on an isolated spur of the highest usable ridge on the summit. I met several people (including a clearly envious Keck staff astronomer) who claim that CFHT occupies the best spot on the mountain. I’m sure that’s debatable, but there’s no question that the view from CFHT is magnificent.

The striking CFHT observatory

The giant 8 and 10 meter telescopes surrounding CFHT dwarf its modest 3.6 meter aperture. Possibly because of necessity, CFHT has consistently adopted new imaging technologies long before other major observatories. Astronomers working out of CFHT continue to produce world-class results.

I’ve always had a soft spot in my heart for CFHT. At the risk of sounding maudlin, it’s like a feisty old bantam, still keeping up with its bigger, newer neighbors. I was thrilled at the chance to explore CFHT.

Of course, there was also the opportunity to take in another Mauna Kea sunset. From the exterior catwalk, the sunset was spectacular. One great advantage was being able to rapidly shift from an eastern viewpoint to a western viewpoint. That let me keep track of both the sunset itself and Mauna Kea’s looming shadow.  I think you’ll enjoy my CFHT Sunset photo set.

New monitors are interspersed with old gauges and controls

After serving freshly brewed coffee and what just could have been the world’s finest shortbread cookies, David took us on an expedition through the observatory. If we missed seeing something, it probably didn’t matter.

The control room was fascinating, particularly for an engineering type like me. Old analog gauges and annunciators revealed CFHT’s late ’70s origins. You don’t see too many push-button switches and indicators with engraved legends any more. Modern digital displays and monitors had been neatly worked into the consoles. The blend of old and new technology showed how the observatory had kept pace with advancing technology.

In fact, the control room is nearly redundant. CFHT can be operated from the headquarters building in Waimea, without an operator in the observatory. David explained how they’d installed an extensive set of sensors and actuators, many designed and built from scratch. For example, special sensors in the telescope floor could even detect hydraulic fluid leaks and trigger a remote alarm. Maintenance specialists on standby notice would be called automatically if a serious problem developed. Since specialists wouldn’t normally be standing by on the summit, there’d be no additional delay in responding to a problem.

Many observatories provide remote observation facilities. CFHT also provides queued observation services, which remote observers such as David handle on behalf of researchers who could be anywhere in the world. From long experience as an astronomy educator, I know this idea disappoints people who imagine that lonely astronomers are still spending long, cold nights peering into eyepieces. Only amateurs (and graduate students) do that any more.

For a “small” telescope, this is a massive piece of machinery.

From the control room, we went down to the telescope floor. Looking up from the floor to the top of the dome gives you a good appreciation of the size of this “small” telescope. The photo to the left gives some sense of the size; this photo set shows more details.

With its massive-looking yoke mount supporting a sturdy truss-work telescope tube, the CFHT reminds me of the Hale Telescope. CFHT is a bit smaller, but it’s also more graceful. This telescope is beautiful.

We had an unusual opportunity to get a very good look at the telescope. The shutter mechanism had broken down two months earlier. The repairs were mostly complete, but the observatory director had decided—sensibly, in my opinion—to do a thorough engineering investigation to figure out why the mechanism had broken in the first place. With the heavy work done, it was safe to go onto the telescope floor. Since the testing wasn’t complete, there was no observing run that night. Out of rotten luck for the observatory, our group had a wonderful opportunity.

With equipment mounts at both Cassegrain focus and prime focus, CFHT provides a lot of options for installing instruments. There’s also an optical train leading to a coudé focus, but that hasn’t been used for some time. The coudé focus room still has a passageway to the telescope mount, but it seems to be a storage room now.

We finished up our visit in a lab space at the bottom of the observatory. A group of engineers and astronomers were working on an interferometry system. It was too windy that night for good results, but what they were seeing was encouraging. Okay, I had to take their word for it. I do understand the basics of interferometry, but not enough to make an intelligent assessment of the interference patterns on an oscilloscope.

Astronomical twilight hadn’t ended by the time we left the observatory, but the sky was dark and studded with hard, sharp stars. Looking southwest, I was a bit disappointed with the Milky Way. It was nothing like the magnificent star-cloud I’d seen the night before. Stars that had seemed vividly colored had no particular color at all.

When we got back to Hale Pohaku, I saw, first-hand, the effects of altitude on vision. Having descended more than a kilometer, the sky was as vivid and brilliant as I’d seen it the night before.

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About Tim Cole

Astronomy enthusiast and educator, all-around fancier of dark skies and starry nights
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