Post on 10-Jan-2016
description
Those who say it cannot be done should notinterrupt the one doing it. -Chinese Proverb
A Discovery Recovery
Or How To Turn A Sonotube Reflector Telescope Into A Truss-
Tube Telescope
A Discovery Recovery
• In 100 steps or less.
1000 more!
^ ^
A Discovery Recovery
Bill O’Donnell – Gopher/holder/fetcher and (ultimately) the guy who gets to take the scope home!
Gordon Major – Draftsman/craftsman/designer
A Discovery Recovery
Discovery 12.5’’f 4.860” focal length
Here’s what we startedwith:
Good scope!Let’s make it BETTER!
A Discovery Recovery
• Objectives– Make the scope
• More transportable• Affordable• Good Looking• To hold collimation
A Discovery Recovery
• An automatic benefit of truss-tube design• Breaks apart• Stores in a smaller space• Requires less space in a vehicle
A Discovery Recovery
• Use as much of the old scope as possible• Use good materials • Cut wood to reserve as much as possible
A Discovery Recovery
Using as much of the old scope as possible
9-point flotation, all metalmirror cell
Primary mirror
Secondary mirror and spider vane
A Discovery Recovery
Using as much of the old scope as possible
Rocker box of Baltic Birch
Azimuth Bearing
A Discovery Recovery
Using as much of the old scope as possible
JMI Crayford Focuser
Altitude Bearings
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Good Looking………….
Choice of woods and finish
Baltic birch (Primary wood)Walnut (Trim)
Spar urethane finish
Walnut veneer (In a place you would least expect it!)
A Discovery Recovery
Holding collimation
Dependant on repeatability of set-up
(we will discuss this later)
A Discovery Recovery
Know what youare starting with.
A Discovery Recovery
Measure and recordeverything about the original scope.
This informationbecomes very valuable later on.
A Discovery Recovery
A Discovery Recovery
Doing as much of themath as possibleearly on saves
a lot of guessworklater.
A Discovery Recovery
Gordy Majorwith a 5’x5’ sheetof Baltic birch
Measure twice and cut once!!!!!
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Nice Touch…..Walnut inlay!
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Go ahead….find the seem!
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Strong corners make for a stronger box!
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By my fourth visit to the Major’s, this is what greeted me intheir living room.
This was the night to do a focustest and figure the length neededfor the poles. (At LEAST atwo person job!)
A Discovery Recovery
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Walnut veneer instead of Kadite
Focuser slides!!!!
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Applying the finishand painting the inside of the box and head.
Quiz time:
Which head isshinier, the scopes or Bill’s?
Nope. Actually itis the scope that isshinier!
A Discovery Recovery
Just look at that SHINE!
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A Discovery Recovery
• Critical areas– Length– Strength (Triangle)– Ease of set-up– Repeatability (same
pole in same hole)
A Discovery Recovery
How did we attach the poles?
Simple….really!
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The top of the poles
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The pole bottoms
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Knob does not come out
Triangle shape adds greater stabilityand repeatability of set-up.
A Discovery Recovery
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Now we get critical!!!!!
Did I mention Measuring????
A Discovery Recovery
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A total of three wood types were used
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It’s gotta be level!
A Discovery Recovery
It all fits just right.
The project is almost finished.
A Discovery Recovery
A Discovery Recovery
The rocker box neededto be widened a bit to make way for the greater width of the box with thealtitude bearings
A Discovery Recovery
BONUS!
A storage areaFor the shroud and a few other small things.
NICE TOUCHGORDON!
A Discovery Recovery
A Discovery Recovery
A sliding mechanismis designed to alloweasy balancing whenweight is added orsubtracted fromthe top of the scope.
Pivot-point
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Each pole is labeledand will only fitin its assigned side
The head will only fit one way.
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Easy access to collimation screwsand fan power plug.
A Discovery Recovery
Now it’s beginning to look like a telescope…… just a little more finishing to do
A Discovery Recovery
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Just a little extradetail to the mirrorcover, a piece ofweather-stripping felt helps the cover fitsnug and keeps the dust out.
A Discovery Recovery
A Discovery Recovery
A total oftwo light baffles.
The top of thebox and one half-way to cell from top.
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Set up is slightlyunder two minutes!
1st Minute
2nd Minute
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Three minutes…..If you put on the Shroud.
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First Light!
And how did itperform?
A Discovery Recovery
The view was spectacular!
A Discovery Recovery
While it took a good amount of time to do thisproject, maybe I shouldn’t have left Judy home alone so often. She is too good at paybacks!
A Discovery Recovery
A Discovery Recovery
Parts and materials = $362.76
Original scope cost w shipping = $1367.00
Cost of new Discovery 12.5” Truss tube w shipping = $2184.00
A Discovery Recovery
PLUS……….
A Discovery Recovery
• We • Designed it the way we wanted it• Got some extras not included in Discovery’s package• One-of-a-kind telescope• And most importantly…….
A Discovery Recovery
We got the Bragging
Rights!!!!!
A Discovery Recovery