http://www.skyandtelescope.com.au 37specially built enlarging cameras and a technique
called integration printing to secure some of the finest
photographs of the planets from that era.
With the arrival of the space age in the late 19 5 0s
and 1960s, the Clark telescope once again became a
centerpiece of lunar and planetary research. NASA
funded a Planetary Research Centre at the observatory,
which carried out two major projects: high-resolution
mapping of the Moon in preparation for the Apollo
missions (resulting in the U.S. Air Force/NASA
Lunar Charts in 196 3), and running the worldwide
International Planetary Patrol Program, headed by
William A. Baum, which generated a database of 1.2
million photographs of the major planets (as told in
the Feb/Mar 2 0 16 issue). These provided invaluable
information on Martian meteorology and dust storms,
the dynamics of Jupiter’s atmosphere, the retrograde
rotation of Venus’s cloud deck, and some of the physical
properties of Saturn’s ring system, all in preparation for
planetary exploration by space probes.
Since then, the great refractor has served as the core
attraction in the observatory’s Public Program, which
welcomes some 80,000 visitors a year. The telescope
has also been used by many amateur astronomers for
special observing and imaging sessions.
But after performing for over a century, the classic
telescope, mounting and dome were in dire need of some
tender loving care. Enter master instrument specialist
Ralph Nye and his team of skilled co-workers: Jeff
Gehring, Glenn Hill, Peter Rosenthal and Dave Shuck.
From the ground up
A major problem was deterioration of the massive
bearing wheel at the bottom of the polar axis.
Forty-six centimetres in diameter and 75 mm wide,
supporting three tonnes of moving parts, it was made
of relatively soft cast iron; large steel bearings weren’t
available in 1 89 5. After some 116 years of use, the
support wheel had flattened and widened at damaged
areas. Consequently, as the telescope moved in right
ascension, the polar axle shifted out of its housing by 3
millimetres or so, and when the three-tonne assembly
fell back to its original position, a loud bang shook the
entire telescope!
Replacing it would require taking the entire
telescope apart. On the positive side, this would give
us a chance to do many other repairs and restorations.
Lowell Observatory started a ‘Save the Clark
Telescope’ fundraising campaign to finance a thorough
job. The institution’s many members and friends raised
close to US$300,000 in three months, enough to totally
restore not just the telescope and mount, but also the
iconic, 12-metre-high cylindrical wooden dome.
CAREFUL! A crane lowers the refurbished, 5,000-kg
equatorial mount through the dome slit.
LOWELL OBSERVATORY(2)DISASSEMBLY A crane lifts the 400-kg declination shaft out of its housing for
inspection and cleaning. The mount was bolted to a temporary pier at a 35° angle,
so the polar axis (behind the big right-ascension circle) would be horizontal for
easier removal of parts.