Australian Sky & Telescope - April 2016__

36 AUSTRALIAN SKY & TELESCOPE APRIL 2016

Lowell Observatory’s 119-year-old legendary telescope has been lovingly restored.

T

he famous 61-cm (24-inch) refractor that stands

atop Mars Hill in Flagstaff, Arizona, holds a

specialplaceintheannalsofastronomy.Itwas

built by the renowned firm of Alvan Clark & Sons

for Percival Lowell, the Mars enthusiast and wealthy

black sheep of a patrician Boston family. The telescope

was commissioned in 1897 and has been in active use

nearly ever since.

Lowell Observatory and its colourful patron seized

the world’s attention at the turn of the 20th century

when Lowell described and mapped the supposed

canals on Mars; he proposed that they were the works

of an advanced civilisation, designed to carry water

from the polar ice caps to the rest of a dying planet.

The ‘canals on Mars’ brought fame and later shame

to the institution, as it gradually became clear that

they were illusory — effects of contrast, atmospheric

seeing, and the tendency of the eye to connect dots and

regularise randomness when working at the limits of

humanvision.OratleastLowell’svisionandthatof

his dutiful assistants.

Despite this controversial beginning, the Lowell

refractor soon made substantial contributions to

science in the capable hands of three pioneering

Lowell astronomers: the brothers Vesto Melvin

(‘VM’) Slipher and Earl C. Slipher, and Carl Otto

Lampland. Among many other achievements, VM

used a modified Brashear spectrograph on the Clark to

obtain the first spectra of spiral ‘nebulae’ and discover

that most showed high velocities of recession. This

achievement led to Edwin Hubble’s finding that the

universe is expanding. VM Slipher also discovered

spectroscopically that the Merope Nebula in the

Pleiades was not glowing gas but interstellar dust

reflecting starlight; it was the first known reflection

nebula. In 1905 Lampland used the Clark refractor

to obtain some of the earliest good photographs of

Mars. For the next half century E. C. Slipher used

FINISHEDThe24-inch (61-cm) f/16 refractor, ready for another

century of service. The 30-cm ‘finderscope’ is mounted above

it; the 10-cm finderscope is out of sight. Access stairs lead to

the classical German equatorial mount. The observatory and

telescope were declared a National Historic Landmark in 1965.

The ‘Mars telescope’ is reborn

E. WEBB

KLAUS BRASCH
& RALPH NYE

Restoring a classic