Astronomy

60 ASTRONOMY • JUNE 2018

Such an opportunity arose in the sum-
mer of 2017, when I joined a small group of
advanced planetary observers at Pic du Midi
Observatory. The memorable few days we
spent there led to some remarkable images.
The group was made up of two profes-
sional astronomers: François Colas, who
works at Pic du Midi and has, for more
than 25 years, imaged with the telescope
we would be using; and Ricardo Hueso, a
planetary scientist with the Escuela de
Ingeniería de Bilbao. Besides me, the ama-
teur astronomers in our group were Marc
Delcroix, an advanced planetary observer
with the French Astronomical Society;
Emil Kraaikamp, the creator of the
Autostakkert software used for planetary
image processing; Gérard Therin, a pioneer
in amateur high-resolution astrophotogra-
phy; and Constantin Sprianu, a planetary
observer from Romania.

A rich history
There’s no doubt you’ve heard of Pic
du Midi Observatory, perched 9,440
feet (2,877 meters) above sea level atop
Pic du Midi de Bigorre in the French
Pyrenees. The observatory, about 90 miles

(150 kilometers) south-

west of Toulouse, has

been a world-renowned site for

astronomical observations for

more than a century.

Construction of the observa-

tory began in 1878, and telescopes rapidly

appeared on the mountaintop thereafter.

The remains of these original buildings are

still on-site. One can only wonder how dif-

ficult it must have been to build an obser-

vatory where heavy snowfall and freezing

temperatures can occur at almost any time

of the year.

Pic du Midi is especially well known for

its history of planetary observations. In the

early 20th century, observations of Mars

made there helped discredit the infamous

theory of martian canals. Many famous

astronomers have observed at Pic du Midi,

including Bernard Lyot of France. In fact,

the largest telescope at the observatory, a

2-meter ref lector, is named in his honor.

Perhaps the most famous telescope at

Pic du Midi is the one we used for our

observations: the 1.06m f/17 Cassegrain

ref lector in the Gentilli dome. This tele-

scope was built in the pre-Apollo era (1963)

and funded by NASA primarily to capture

detailed images of the lunar surface for

mission planning. After the telescope saw

first light, astronomers found the optics to

be of only average quality, so French mas-

ter optician Jean Texereau, a well-known

figure to amateur telescope-makers, refig-

ured them.

From the 1960s through the 1990s, the

telescope was mainly used for planetary

photography. Many of the finest photo-

graphic film images of the planets were

taken with it. Recently, researchers have

used the telescope only sporadically for

planetary observations, and this fact led to

the realization of this observing mission.

The team arrives

In 2016, Colas, the lead astronomer of the

1.06m telescope, spoke with a few French

amateurs who had regularly visited the

observatory over the past several years. He

The observing team stands alongside

the dome of the 1.06-meter

telescope. From left are Ricardo

Hueso, Damian Peach, Marc Delcroix,

Gérard Therin, Constantin Sprianu,

Emil Kraaikamp, and François Colas.

DAMIAN PEACH

The telescope is operated from the

laboratory directly below the dome,

but the initial setup of locating the

target object and installing the camera

has to be done in the dome itself.