Old Dominion Obs, Canada

excellente'


"Il mio nome è Nessuno" wrote:

"W. eWatson" wrote in
:

I understand the Dominion Obs closed back in 1970. Did their library
get absorbed into a new facility. How could I contact anyone that
might know?


http://www.nrc-cnrc.gc.ca/eng/news/n...servatory.html

http://www.nrc-cnrc.gc.ca/eng/facili...astrophysical-
observatory.html

Highlights - Long a history-maker, now an historic site

July 28, 2010 — Victoria, British Columbia

On a 230-metre mountain just north of Victoria, the Dominion
Astrophysical Observatory (DAO)’s 1.8 metre reflecting telescope has
probed the night skies for 92 years. It’s apt now that Parks Canada
should designate the observatory as a national historic site to recognize
its importance to Canadian astronomy’s development.

“The DAO and its early staff helped bring Canadian astronomy to an
extremely high level of international regard,” says its director, Dr. Jim
Hesser. He adds that the Parks Canada designation allows NRC to maintain
the Observatory as a working scientific instrument while respecting its
historic architecture.

Warner and Swasey Co. of Cleveland, also a supplier to Ottawa’s Dominion
Observatory, designed the Dominion Astrophysical Observatory’s larger
rotating steel dome and installed it in 1917.

According to Dr. Hesser, the Observatory building’s design may still say
“1918” to casual eyes, but nearly a century of accumulated upgrades make
the telescope 10,000 times more sensitive than it was when new — and thus
capable of contributing to 21st century astronomical research.

The 1.8 metre diameter Belgian-cast glass primary mirror that first
caught starlight on May 6, 1918, was replaced in the mid-1970s with one
that is unaffected by temperature changes. The original spectrograph — an
instrument that breaks down a star’s light to determine its chemical
composition — has been upgraded many times. Digital cameras and a new
polarimeter developed by the NRC Herzberg Institute of Astrophysics (NRC-
HIA) have taken advantage of emerging technologies. But the building,
Observatory dome and nine-metre steel telescope frame remain original.

“It’s pretty remarkable that after all these years, we’re still using
much of the same equipment,” says Dr. David Bohlender, the NRC-HIA
research officer in charge of the telescope. “We have plans to continue
to enhance its operation over the coming years and look forward to
carrying on the reputation of the Observatory.”

Old-fashioned horsepower carted the high-tech reflecting telescope’s
heavy equatorial mount up to its home on Little Saanich Mountain (now
Observatory Hill).

Dr. Hesser adds that the telescope’s original tracking mechanism — a
“very beautiful” gravity-driven brass clock drive — remained so accurate
that it was only disconnected in the late 1980s, in favour of a new
computer system that automates telescope guiding and improves the
accuracy of its pointing.

While much of Canadian astronomy’s focus has shifted toward larger and
newer facilities such as the Canada-France-Hawaii and Gemini telescopes,
such upgrades keep the DAO “in the picture.” Dr. Bohlender says the
Observatory’s main strengths include hosting long-term observing
programs, providing long blocks of uninterrupted observing time, and
training next-generation astronomers for their scientific careers.

An ongoing program at the Dominion Astrophysical Observatory charts the
orbits of potentially dangerous asteroids that pass near the Earth.

The man who built the DAO

Dr. John Stanley Plaskett, the DAO’s designer and first director, was a
trained machinist who had been an instrument mechanic at the University
of Toronto’s physics department.

He became an astronomer at the Dominion Observatory’s 0.32 metre
telescope in Ottawa after gaining his doctorate. Dr. Plaskett’s belief in
simple, strong design is one reason why the Observatory on Vancouver
Island has held up well for so long. And it helped establish NRC-HIA’s
worldwide reputation for developing scientific instruments for optical
and infrared telescopes.

In fact, this reputation continues to this day, and NRC-HIA still relies
on the DAO telescopes as test beds for new instrument designs.

DAO director Dr. Jim Hesser says the national historic site designation
recognizes the scientific vision of Dr. Plaskett and the Observatory’s
early staff, as well as the Observatory’s physical structure.

“We are very proud that this designation has been awarded to the
Observatory, and we’re also proud that, more than 90 years later, the
Plaskett telescope is still contributing,” says Dr. Hesser. “The
telescope also plays an important role in bringing the wonders of
astronomy to tens of thousands of school children who visit us every
year.”

Groundbreaking discoveries

When new, the DAO was briefly the largest operating optical telescope in
the world. One of its first discoveries arose from a decade-long program
that used the then new technique of spectrographic photography to chart
the “radial velocities” — the speeds at which they approach or recede
from the Earth — of hundreds of stars. This led to groundbreaking
discoveries about our home galaxy, the Milky Way — DAO research published
under Dr. Plaskett in the 1930s was the definitive word on the Galaxy
until radio astronomy came online in the 1950s.

“It led to an absolutely fundamental result in our understanding of the
size and the mass of the Milky Way Galaxy,” says Dr. Hesser.

The Observatory’s early astronomers also used spectrographic analysis to
identify the nature of what is now routinely called the interstellar
medium — gas and dust in the vast spaces between the stars. A quarter-
century later, astronomers realized the interstellar temperatures derived
from these observations helped prove the universe’s Big Bang birth.

Another fundamental contribution was the 1922 discovery of the most
massive binary star known until recently — astronomers now call it
Plaskett’s Star.

An ongoing program charts the orbits of potentially dangerous asteroids
that pass near the Earth. And today, astronomy graduate students from the
University of Victoria are classifying recently discovered supernovae
with time scheduled every few weeks.

Many of the DAO’s early discoveries are so fundamental they’re now common
knowledge to grade-school science students, but early last century they
were groundbreaking. Dr. Hesser says this underlines the fundamental
nature of the Observatory’s work.

“It has served us extremely well and it’s still producing good science,”
he says. “For very little expenditure from NRC-HIA, the two DAO
telescopes still contribute.”

The Plaskett Telescope

The Dominion Astrophysical Observatory’s first director, Dr. J.S.
Plaskett, clearly had international-grade research in mind from the
start. His designs for the DAO’s original observatory and telescope were
so well-thought-out that seven later observatories were modelled on the
same blueprints — the last one in the 1960s.

“He was involved in every aspect — engineering, design, commissioning and
then laying out the groundbreaking observing program. He set very high
standards for research,” Dr. Jim Hesser says. “He and the other staff
helped inspire Canadians to pursue lofty goals in astrophysical research,
and to compete on an international level. It’s both the building and the
telescope as well as the heritage of the staff’s wisdom that I think are
honoured by the national historic site designation. In the history of
modern astronomy, Plaskett and his associates were giants.”

“Plaskett was an innovator,” adds Dr. David Bohlender. “He took advantage
of the very best technology of the era in the designs of both the DAO’s
telescope and its spectrograph, always with a view to making the
equipment very robust.”

In 1962, a separate dome with a smaller, 1.2 metre telescope dedicated to
spectroscopy was built on site. The DAO became part of the NRC Herzberg
Institute of Astrophysics (NRC-HIA) in 1970.

The original 1.8 metre instrument, used for spectroscopy about three-
quarters of the time and direct imaging for the rest, was named the
Plaskett Telescope on its 75th anniversary in 1993.

Related information

Astronomers capture first images of another solar system
Canadians share the wonder of the night skies
CANFAR connects astronomical dots
Seeking answers in the stars
Parks Canada: Government of Canada Celebrates the National Historical
Significance of the Dominion Astrophysical Observatory
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