Sky and Telescope - March 2016 - 36

Restoring a Massive Antique
scope" fundraising campaign to finance a thorough job.
The institution's many members and friends raised close
to $300,000 in three months, enough to totally restore
not just the telescope and mount, but also the iconic,
40-foot-high cylindrical wooden dome.
Lowell Observatory has a long tradition of designing
and fabricating instruments and telescope modifications, and it has always retained a cadre of specialists
and facilities to that end. This saved money and provided
the in-house expertise to do the best possible restoration job without cutting corners. For example, coauthor
Ralph Nye, Director of Technical Services, has worked at
Lowell since 1976. He's in charge of mechanical engineering and maintains the Clark and eight other telescopes, including instrumentation for the observatory's
new 4.3-meter Discovery Channel Telescope.
No documentation exists for how the telescope was
originally put in place. So Nye's restoration plan centered
on taking the instrument apart safely (photographing all
parts and their locations), designing and fabricating custom arrangements to process some seven tons of parts,
and restoring the wooden dome without damaging it.
The undertaking involved several key steps. First, we
locked down the telescope's 32-foot tube parallel to the
ground using two special fi xtures that bolted to existing
holes on the cast iron center section of the tube, then
attached these to the mount pedestal using specially
designed turnbuckles reminiscent of a truck driveshaft.
A similar brace was used to support the five 417-pound
right-ascension counterweights.

LOWELL OBSERVATORY (2)

DON'T SCRATCH Left: The 24-inch objective lens after
removal of the lens cap and the adjustable-aperture iris diaphragm that early observers sometimes used. Despite a coating
of dust and pollen, the lens was otherwise in good shape.
Right: Ralph Nye (left) and Peter Rosenthal carefully clean the
rear, flint-glass element of the disassembled 24-inch objective.

36

March 2016 sky & telescope

We carefully removed several trees near the dome to
allow room for a 160-foot crane to remove large components through the dome's shutters. To facilitate this, we
stripped the telescope of all small parts, along with its 4and 12-inch Alvan Clark and Sons finder telescopes.
The priceless 24-inch Clark lens assembly was next
in line for removal, but this posed a problem. Since the
telescope was now locked in place horizontally, the dome
could not be rotated freely to allow access to the lens
through the dome shutter. We cut a hole in the dome
ceiling and lowered a 40-foot strap to lift off the 230pound lens cell! Before that, however, we had to remove
two of the counterweights to balance out the expected
weight loss due to removal of the lens assembly and,
later, the upper and lower tube sections.
Prior to removing the 860-pound front tube section,
we braced a massive wooden beam between the floor
and the back section of the tube for added safety and to
minimize stress on the temporary support rods.
Since the mount's polar axis is aimed 35° above horizontal (Flagstaff 's latitude), and the 960-pound polar
shaft would be extremely difficult to remove at such an
angle, Nye designed an I-beam support structure set at
-35°, to tilt the whole mounting at an unnatural angle.
This allowed removal and reinstallation of the polar
shaft with a horizontal pull or push.
The telescope had last been serviced several decades
before, and at that time many of its parts were treated
with lead-based paint to minimize corrosion. To address
the lead-paint toxicity problem, we built a wooden
fi xture allowing the two telescope tube sections to be
rolled and treated with a lead-paint stripper and neutralizer. We refinished the tube and many other large parts
with a silver-grey powder coating. All other parts and
accessories were cleaned and restored to the point where
we could do nothing more to make them work or look
any better.



Sky and Telescope - March 2016

Table of Contents for the Digital Edition of Sky and Telescope - March 2016

Contents
Sky and Telescope - March 2016 - Cover1
Sky and Telescope - March 2016 - Cover2
Sky and Telescope - March 2016 - 1
Sky and Telescope - March 2016 - Contents
Sky and Telescope - March 2016 - 3
Sky and Telescope - March 2016 - A
Sky and Telescope - March 2016 - B
Sky and Telescope - March 2016 - 4
Sky and Telescope - March 2016 - 5
Sky and Telescope - March 2016 - 6
Sky and Telescope - March 2016 - 7
Sky and Telescope - March 2016 - 8
Sky and Telescope - March 2016 - 9
Sky and Telescope - March 2016 - 10
Sky and Telescope - March 2016 - 11
Sky and Telescope - March 2016 - 12
Sky and Telescope - March 2016 - 13
Sky and Telescope - March 2016 - 14
Sky and Telescope - March 2016 - 15
Sky and Telescope - March 2016 - 16
Sky and Telescope - March 2016 - 17
Sky and Telescope - March 2016 - 18
Sky and Telescope - March 2016 - 19
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Sky and Telescope - March 2016 - 21
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Sky and Telescope - March 2016 - 28
Sky and Telescope - March 2016 - 29
Sky and Telescope - March 2016 - 30
Sky and Telescope - March 2016 - 31
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Sky and Telescope - March 2016 - 33
Sky and Telescope - March 2016 - 34
Sky and Telescope - March 2016 - 35
Sky and Telescope - March 2016 - 36
Sky and Telescope - March 2016 - 37
Sky and Telescope - March 2016 - 38
Sky and Telescope - March 2016 - 39
Sky and Telescope - March 2016 - 40
Sky and Telescope - March 2016 - 41
Sky and Telescope - March 2016 - 42
Sky and Telescope - March 2016 - 43
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Sky and Telescope - March 2016 - 45
Sky and Telescope - March 2016 - 46
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Sky and Telescope - March 2016 - 48
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Sky and Telescope - March 2016 - Cover3
Sky and Telescope - March 2016 - Cover4
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