http://www.skyandtelescope.com.au 73WIRE-FRAME AND SOLID FOCUSER: ROBERT ASUMENDI
command and print another one.”
Most of the upper end is 3D-printed.
Robert used a carbon-fibre-infused
nylon material that’s lightweight,
durable and stiff. The interior space
of most pieces is honeycombed rather
than solid, so they’re considerably
lighter than wood and they have almost
zero flex. The biggest challenge with
binocular scopes — keeping the images
merged as you move the scope around
the sky — is a non-issue
with Robert’s scope.
The bottom end is
more conventional, with
aluminium trusses and
plywood mirror box and
rocker box. Why didn’t
he 3D-print all that,
too? “Because all that
stuff is best realised in
other materials using
other processes,” he
explains. “Plus 3D
printing is relatively
expensive over large
volumes.” However, the
parts of the scope that
aren’t 3D-printed were
CNC-routed or laser-
cut, so all the design
could still be done in
one piece of software.
Robert bought his
mirrors but designed hisowncellsto
support them. And ratherthanfine-
tune the image mergingbytiltingthe
primaries, as most binocularscopesdo,
he chose to do his imagemergingatthe
tertiaries, where the adjustmentknobs
are easy to reach.
Given the stiffness ofthecarbon-
fiber-infused nylon buildingmaterial
and the telescope’s overallrigiddesign,
there’s very little adjustingnecessary.A
tweak after setup and theviewis often
good all night. The scopecanmovefrom
horizon to zenith withouttheimages
separating, and switchingeyepieces
doesn’t affect merging untilRobertgets
to his highest magnification.Eventhen,
it’s a simple matter to re-merge.
One of the biggest problemsof
binocular scopes is theircomplexityin
setting up. Setting up Robert’sscopetakes about a minute: Place the scope
and base on the ground, slide the top
end upward and lock it into place, pop
a couple of eyepieces in, fine-tune the
merging, and you’re ready to go.
The eyepiece holders are another
great innovation that neatly solves a
common frustration with binocular
scopes. Set screws and compression
rings tilt the eyepieces, especially when
the eyepieces have safety undercuts.
In a binoscope, that
plays merry hell with
image merging. Robert
solved that by printing
individual collars for
eacheyepiece.The
collarsincorporate
neodymiummagnets
thatclickthemneatly
intoplace— exactlythe
sameplaceeverytime,
completelyeliminating
set-screwtilt.
Robertalsodesigned
filtercartridgessohe
canpopvariousfilters
inandoutofthelight
pathwithoutremoving
eyepieces.Those,
too,areheldinplace
magnet ically.
That’sthebeauty
ofdesigningthescope
digitallyand3D-printingit:theability
torefinetheuserexperience.Robert
says,“Withmybinoscope,I wanted
peopletobeabletojustwalkuptoit
anduseit intuitively.”Hehaslargely
succeeded.I’vewatchedpeopleuseit
at starparties,andtheyfigureit outwithin seconds. To adjust the eyepiece
separation for their own eyes, they
just grab the eyepieces and push them
together or pull them apart. The focus
knobs are right where you expect them
to be. You grab the top end of the scope
to move it around the sky.
Robert calls his scope the ‘Drifter’
because it’s supremely suited to simply
scanning the sky in search of beautiful
sights. With a wide-field binocular scope,
every view is a stunning view, but there’s
a sense of special delight in sweeping
across, say, the Dumbbell Nebula
without specifically looking for it.
That sense of delight is what it’s all
about. As Robert says, “I didn’t build
a telescope because I wanted to try 3D
printing. I started 3D printing because I
wanted to build a binoscope that never
ex isted before.”
We’re on the threshold of a new
design revolution. I’m convinced that
Robert’s experience, both the building
method and the end result, will get
more people into amateur astronomy.
And there are still a million unique
scopes waiting to be imagined and built.
For more information, contact Robert
Asumendi at [email protected].■ Contributing Editor JERRY OLTION is
a big fan of binocular scopes, 3D-printed
or otherwise.pThe top end of the Drifter is mostly
3D-printed. One side is uncovered to show
interior hollows and secondary spider design.pRobert’s computer is his workshop.pThe focuser design can be
displayed as a wire-frame drawing
or as a solid object.