The 46 m (150 ft) antenna at Algonquin Radio Observatory is
Canada's largest antenna. Commissioned in 1965, the telescope is a fine
example of a monster machine. The giant dish is fully steerable and can
track with arc second precision the faintest object in the sky. Powerful
motors turn the giant antenna in azimuth and elevation to point at any
location in the sky. The moving part of the antenna rests 1000
tonnes on the pedestal base. The antenna was designed by
consulting engineers Freeman Fox company and constructed by the
Montreal-based Dominon Bridge Co. on
behalf of the National Research Council of Canada. Construction
of the instrument required
a giant crane that was shipped from the United Kingdom especially for
the project. The antenna was surveyed by N. W. Broten using theodolite
and metal tape held under
tension into order to achieve a surface precision of about one
millimeter. Giant steal plates, each formed into a section of a parabola,
created the surface. The plates were adjusted and tuned manually in order to optimize
the performance of the dish. A later survey
by T. H. Legg et. al using single-receiver holography in 2003
indicates that the dish surface still meets it's original performance
requirements today.
Freeman Fox also designed Algonquin's sister dish at the Parkes
Observatory in Australia.
Mechanically identical to ARO, the Austrialia telescope has a slightly
larger surface as it was not required to observe wavelengths shorter
than 21cm, increasing construction tolerances. The telescope at Parkes was responsible for
returning video
of the first lunar landing during Apollo 11.
A restoration project is
now in full swing to bring the Algonquin Radio Observatory and antenna
back to pristine condition. Come and see one of Canada's least well know engineering
marvels and follow the progress.
