Success story: Design and Fabrication keeps the NRC’s telescopes in tip top shape

Did you know that telescope mirrors can deteriorate over time if not properly maintained? Environmental conditions, dust, dirt and even bird droppings, can create small voids on the mirror’s surface where light can pass through.

Our Design and Fabrication Services (DFS) help keep our telescopes in tip top shape by providing cleaning and recoating services. This maintenance is essential to ensure we continue to get the highest possible quality of data from our telescopes.

“Our mission is to enable our researchers to carry out their research by building new tools and maintaining our leading-edge facilities,” says Camile Lebrun, Director of Production at DFS.

The 1.2-metre telescope at our Dominion Astrophysical Observatory in Victoria, British Columbia, was recently maintained by Felipe Miranda, Supervisor of Fabrication with DFS, along with Dmitry Monin, Technical Officer at our Herzberg Astronomy and Astrophysics Research Centre (HAA).

Cleaning and recoating the mirrors on a regular basis is necessary because the aluminum mirror coating deteriorates over time due to environmental conditions, dust, dirt and even bird droppings. The deterioration of the coating causes small voids on the mirror surface where light can pass through, which can cause a blurry or warped image.

From dust to dazzle: the telescope mirror restoration process

To complete the maintenance, the team first removed the primary mirror from the telescope and lowered it through a hatch in the floor to the coating plant located below the telescope. The deteriorated aluminum coating was then chemically stripped from the mirror and the glass was cleaned using pure soap, distilled water and lint-free cloths.

Next, they loaded the clean glass into a vacuum chamber containing clean tungsten coils wrapped in pure aluminium. Once sealed, the air is removed from the chamber using vacuum pumps.

?Finally, the team powered the tungsten coils, which glow like incandescent lightbulbs, until the aluminum wrapped around them melted and wicked into the tungsten coil. A quick increase in voltage vaporized the aluminum, depositing it onto the mirror surface.

The week-long recoating process has been part of the telescope maintenance program for years, with a dedicated coating plant to aluminize the glass located within the observatory.

“Although the 1.2-metre telescope has been around for 63 years, it is still operating as a research instrument every clear night, along with a 1.8-metre telescope, which has been operating for 106 years,” comments Neal Kelly, Senior Lead of Fabrication.?

“With this in mind, it is important that the telescopes are maintained on a regular basis, and we take immense pride in doing this work. We are stewards of these telescopes, keeping them operational and providing maintenance that is crucial to their ongoing performance today and in the future.”

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