Sky and Telescope - October 2017 - 33

p SHAPING THE ROOF Each section of the dome roof was bent into
shape using a large slip roller.

mesh offer an excellent gripping surface for the foam adhesive that holds the bricks on.
The roof, an aluminum skeleton with riveted metal sheet
cladding, is very similar in design. I didn't use real copper
for the exterior because it's heavy, expensive, and difﬁcult to
shape into the decorative parts required by the aesthetics of my
design. So instead, I used aluminum sheet for the panels and
ﬁberglass castings for the cupola and decorative corbels. After
much experimentation, I developed a paint effect that gives
any surface a very similar look to verdigris on copper.
When it came to the interior, my wife Asia and I wanted
the observatory to be a fun place to hang out. It needed to feel
cozy in spite of being essentially an unheated outdoor shed.
As artists, we were also very keen that it should be a beautiful celebration of the night sky. Since the internal ceiling is a
dome, we thought it would be great to have stars on it - even
better if they were set amongst mythological ﬁgures.
In the library of my alma mater there's a celestial globe
that a colleague had created from engravings by the great
17th-century cartographer Vincenzo Coronelli. Seeing this
magniﬁcent globe made me determined to use the same
artwork on the inside of our dome so that, in effect, you'd be
standing in the middle of Coronelli's universe.
One problem was that, like most early globe makers, Coronelli imagined that the stars existed in a ﬁ xed crystal sphere
around the Earth. So what he drew was a view of the constellations as seen from outside of that sphere, looking down on
the stars and the Earth below. The trouble with translating
such a globe onto the internal roof of an observatory is that
an observer looks outwards from within the sphere, not in
from outside. As a result, everything, including the order
of the constellations around the sky, is left-right reversed
compared to the globe. Of course, the star patterns and the
illustrations around them can easily be ﬂipped over, but
Coronelli also included thousands of star and constellation
names, inscriptions, notes, and markings - each one had to
be manually reversed in Photoshop so they weren't backward

when the main artwork was reversed. I'm sure my wife recalls
my complaints once or twice about this tedious job.
The ﬁnal artwork was printed out onto aluminum panels
using a big industrial sign printer and UV setting inks -
which are 100% weatherproof and in theory should last a lifetime. The panels were then bent into the proper contour using
rollers and then riveted onto the interior frame of the roof.
The ﬁnished observatory is a lovely space to sit and enjoy
the magniﬁcence of the night sky. We're lucky to live on the
edge of the Exmoor National Park Dark Sky Reserve (https://
is.gd/dark_sky), so the skies are particularly dark and stunning here. With the observatory's interior red lights dimmed,
the real stars shining through the shutter sit beautifully
alongside Coronelli's fantastic creatures progressing around
the ceiling. Even on a windy night observers stay reasonably
warm and the telescope remains steady. The interior is far
from roomy, but it's big enough for two people.
Setting up for an observing session simply involves unlocking and opening the shutter, then removing the lens caps
from the telescope, all of which takes less than a minute.
Perhaps most importantly, there's no heavy lifting or straining involved. Having once owned a very large "portable" telescope that was a real workout to move, I really appreciate that
avoidance of physical exertion. The prospect of heavy lifting
is especially daunting at the end of an observing session when
I'm often cold and tired. It's not something I miss at all.
Not everyone is lucky enough to have the ability to build
an observatory, but if it's feasible for you to do so, I would
highly recommend it. Having a permanent home for your
telescope will signiﬁcantly increase your observing time.
¢ TIM WETHERELL is an accomplished artist and amateur
astronomer. Visit his website at timwetherell.com.

BEAUTY WITHIN The author with his wife Asia and the premier
instrument of the observatory, an attractive, Victorian-style
7-inch f/7 apochromatic refractor.

s k y a n d t e l e s c o p e . c o m * O C T O B E R 2 0 17

http://www.is.gd/dark_sky http://www.is.gd/dark_sky http://www.timwetherell.com http://www.skyandtelescope.com

Sky and Telescope - October 2017

Table of Contents for the Digital Edition of Sky and Telescope - October 2017