12 inch F/5 Binocular
Telescope
· 14” sonotube and ¾ inch exterior plywood are primary building materials used
· 5” wheels for portability allow scope to be easily moved - note blue lift strap
· ground board permanently attached
· tubes permanently attached to cradle
· cradle/tubes secure to rocker box for travel – entire scope is moved as a unit
· total weight 125 pounds
· oil base primer/white deck paint on exterior.
· oil base flat black tube interiors
· primary mirrors mounted to ¼” masonite pads with double sided foam tape
·
cradle
corner braces provide torsional strength
·
tubes
independently mounted, one in x axis, other in y axis – adjusted while viewing
·
each
tube is independently collimated and then left undisturbed
· Upper tubes rotate to allow interocular adjustment
· x/y coupler/adjuster is conveniently located between tubes
· coupler permits adjustment of the tubes in x and y axis while viewing to insure convergence
Encouraged by the performance of the 12 inch minimalist scope
built to test the 12” primary mirrors, I decided to make a minimalist 12”
binocular scope. I got it done with a
total weight of 60 pounds. First light
revealed all sorts of vibration which made the images look like the Dow stock
averages. I isolated the causes of the
vibration but couldn’t eliminate the problems – finally abandoned the scope and
did a 180 degree turn to low tech solutions.
Nitelite is the result. This somewhat
pedestrian looking scope is rock solid
stable, has very smooth altitude and azimuth motions, permits “on the fly” at
the eyepiece adjustment of the two optical tubes to achieve and maintain
convergence or “fusion” of the two images.
This ability is particularly important when viewing at high power. The x/y coupler/adjuster detailed here solves the Achille’s
heal of binocular scopes – a “while observing” means to conveniently adjust
image convergence without disturbing
individual tube collimation . The tubes
balance coincident with the center of the altitude bearings, insuring that if
the tubes are aligned to achieve image convergence near the zenith, convergence
will “hold” as the scope is rotated to the horizon. My test of any scope is whether or not it
becomes “transparent” during the observing session or becomes the “center of
attention.” Nitelite fades into the
background permitting observing without distraction. First light revealed all of the members of
Stephan’s Quintet and 6 trapezium stars in the Great Nebula in Orion. Despite significant weight and size, the
scope can be moved about the house with ease, loaded in my Jeep quickly and
arrives at the observing site ready for observing after 4 hold down bolts are
removed – Jeep to observing in 5 minutes including double check on collimation
with Cheshire. This may prove to be my
scope most used.
It is now May, 2007 and the scope has been to