My first Magazine Sky & Telescope - 04.2019 | Seite 75

themselves in and out for focus.
Baffl ing between the secondary mir-
rors is important. If either eyepiece can
see the wrong secondary, then it will
present ghost images. Frank is careful to
limit the light paths so each eyepiece can
only see the secondary it’s supposed to.
One of Frank’s more unusual designs
is the scope he calls “Popeye,” which
uses mirrors of different diameter. He
had a 10″ f/7 mirror and a 12.5″ f/6
whose focal lengths were within about
3″ of each other, close enough to use in
a binoscope. So he put the larger mirror
on the far side, where its extra diam-
eter would compensate for the larger
secondary, and it worked beautifully. He
didn’t bother with a full secondary cage,
opting to run the edge of a rectangular
cage right through the light path and
mounting the secondary on that. I have
viewed through Popeye many times and
can attest that it works like a charm.
p Frank’s 10” binoscope is a hit with his grand-
daughters . . . and with everyone else who
looks through it.
Indeed, all of Frank’s binocular
scopes (he’s done four now) offer
superb views, and all with just four mir-
rors each. As Frank says, “It often takes
a little tweaking to merge the images,
but when they do, something magical
happens and the view just looks more
real and three dimensional.” And that,
dear reader, is why we binocular nuts go
to the trouble. You could, too, without
even needing tertiary mirrors.
For more information, contact Frank
Szczepanski at [e-mail] .
We’re So Puzzled
You can be, too! Choose from our selection
and assemble a stunning celestial object.
350-piece Mars
f rom Viking 1 orbiter photos
350-piece Moon
from Lunar Reconnaissance
Orbiter imagery
Puzzles make great gifts!
504-piece
Mystic Mountain
from Hubble images
■ Contributing Editor JERRY OLTION
is an avowed binocular nut, and it’s all
Frank’s fault. Thank you, Frank!
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