12.5" Captain Nemo's
|2nd Place Craftsmanship, 2nd Place Mechanical Design,
Merit Award, Astronomer's Choice Award, RTMC 2009
Ross Sackett's amateur telescope making
A scope for Capt. Nemo
If Jules Verne had owned a Dobsonian telescope, what would it look like?
The concept for this scope grew out of online discussions with Philadelphia
ATM Jay Scheuerle and others about our mutual fondness for “Steampunk”
design. Steampunk is a contemporary art movement that blends modern
technology with Victorian aesthetics, yielding chimeric hybrids such as fully
functional laptop computers sheathed in rich mahogany, polished brass,
and gears and sprockets. This telescope is my steampunk interpretation of
a single-ring ultralight Dobsonian that might appeal to a Nineteenth Century
The single-ring UTA is made of a ply-balsa-ply sandwich to save weight.
The spider has offset vanes, which make it much stiffer in rotation than
conventional radial vanes. The ornamental cutouts represent a twining
vine. The glare shield is made of fiberglass-epoxy veneered on one side,
with black velvet on the other. There is a variable iris beneath the focuser
to further limit stray light. I am very proud of all the homemade brass work,
especially the finder bracket!
The six 7/8” OD copper truss tubes are anchored by brass brackets. The
12.5” primary mirror sits in a 6-point cell. The hinged mirrorbox lid is held
open by a magnet. The cover is decorated in veneer marquetry with a coat
of arms based on the Incan royal banner; I borrowed the heraldic motto
from 2001: A Space Odyssey. The scope’s baltic birch plywood is covered
in ribbon-cut African mahogany veneer with a shaded stain and
polyurethane varnish finish.
The two upper collimation knobs are connected by sprockets and roller
chains to copper poles so that I can collimate the telescope from the
eyepiece. At last, collimation is fun! (By the way, after the first set-up,
never touch the third knob!)
A sliding bolt and four catches lock the mirrorbox to the rocker so that the
telescope can be rolled on the permanently attached wheels. The scope is
easily moved up and down stairs, through doorways, and around the yard.
At Stellafane 2008 Captain Nemo won second place awards in
craftsmanship and mechanical design, behind Dick Parker's and Alan Hall's
INCREDIBLE twin 16" cassegrains. It was an honor to be up on the podium
with those guys. In May 2009 it won the Astronomer's Choice Award at the
Riverside Telescope Makers Conference.
By the way, to keep my ego in check my uncle refers to this telescope as
"Ross's Victorian lawnmower."
My telescopes and ATM Projects