Monique Keiran: B.C. input will help shed light on Earth’s atmosphere

Light takes less than 20-millionths of a second to travel the 5.85 kilometres between Observatory Hill and Mount Douglas in Saanich. I stand at the summit of the latter, looking at a large new building on the south slopes of the former.

The equipment to be tested within that building will be used to help detect light that has travelled 13 billion years or more across space and time to Earth.

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In astronomy, time is distance.

The building, Scott Roberts tells me, is the integration and test facility for instruments B.C. astronomers and engineers are designing and building for large telescopes around the world.

The telescopes include the CHIME radio telescope near Penticton (one light-millisecond from Victoria), the Canada-France-Hawai’i Telescope, in Hawai’i (14.3 light-milliseconds away), the Gemini Observatories, in Hawai’i and Chile (34 light-milliseconds), and now the Thirty Meter Telescope (TMT), which doesn’t yet have a home — if not Hawai’i, the Canary Islands (29 light-milliseconds).

Roberts is acting director of Astronomy Technology at the National Research Council’s Herzberg Astronomy and Astrophysics division at Observatory Hill.

He is overseeing the design and eventual construction and testing of two key instruments for the TMT, a massive telescope with a 30-metre segmented primary mirror being designed and built by a five-country team of researchers and engineers.

One of the Canadian instruments will help the telescope see starlight clearly through Earth’s atmosphere.

“Adaptive optics, when used in astronomy, measures and compensates for atmospheric distortion, resulting in a huge gain in sensitivity for a telescope,” Roberts says.

Our atmosphere is constantly moving, causing starlight passing through it to refract and twinkle. When that twinkle hits a telescope mirror, it creates an imprecise, blurry image that causes problems for astronomers doing research.

The adaptive optics system that will be one of the first instruments tested in the new Observatory Hill building will remove that twinkle. The system is designed to detect and analyze the atmospheric turbulence in starlight’s path. A computer then calculates how to correct those distortions and instruct the mechanism that controls the telescope’s adaptable mirror assembly.

“These mirrors can change shape 800 times each second to adjust for, in real time, the optical distortions the atmosphere introduces,” Roberts says. The result will be a sharp, focused image that the system will feed to the various instruments that make the measurements astronomers use in their research.

Thanks in part to this B.C.-designed, -built and -tested instrumentation, “the TMT will have 200 times the gains in light sensitivity over Gemini,” Roberts says. The Gemini telescopes are the next-biggest ground-based optical telescopes Canada has a partnership stake in.

The increased sensitivity means that once the TMT is built and operating, researchers will be able to study planets circling distant stars or explore further back in time and space towards the Big Bang.

The adaptive optics team, which includes researchers and engineers from Herzberg, UVic, UBC and companies in Squamish and North Vancouver, is ready to begin building and testing the system’s various components.

They’re also ready to start building the second instrument Canada is contributing to the TMT — an imaging spectrometer designed to operate in the near-infrared part of the spectrum. It will record images and spectra of astronomical objects at resolutions and brightnesses that are currently unprecedented. The spectrometer plugs into the adaptive optics system, as needed, and will be one of the first science instruments to collect research data when the telescope starts operating.

With the TMT adaptive optics system measuring about half the size of a tennis court and about three metres tall, the new integration and test facility here in Victoria has to be large, too. The new building contains a large overhead crane for lifting and moving components. It also houses electronics laboratories, detector labs, and lab benches to model and test the performance of the telescope instruments. Deep-freeze chambers that will be kept at -30 C will allow the team to test the instruments for the TMT and other telescopes at the temperatures they need to operate at for best results.

The new facility is scheduled to be completed by the end of August, Roberts says, while the TMT has another decade or so to go before it is built and operational. That’s another 10 or so years for starlight to travel here from faraway stars at almost 300,000 metres per second.

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