dave b
Post Laureate
Reged: 05/10/05
Posts: 3534
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http://dobstuff.com/23scope.htm
im sure many of you have already seen this, but it is cool none the less.
23" mirror, 4" thick, made of Ultra Low Expansion glass, polished on both sides.
i would not exactly call it an ultralight, but it is a great design
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dave bonandrini
30" f/5.2 Dobsonian
President of GCAC
Astromart Moderator
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Don W
Postmaster
Reged: 05/19/03
Posts: 14621
Loc: Wisconsin, USA
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I LIKE it!
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Don Wyman
Obsession 18" f/4.5 #1166
W/Argo Navis DSC and Torus Primary
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7190
Loc: Issaquah, WA.
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Thats a great looking scope and built pretty well from the description. I wonder what the cost will be.
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Equipment Overload!
Kerry
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skyward_eyes
Carpal Tunnel
Reged: 12/12/06
Posts: 2101
Loc: Arizona
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I have been talking to dob stuff about doing a 24" f/4. He mentioned he was finishing up a 23" project for someone. Glad to see its done, looks great!
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www.skywardeyes.webs.com
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Darren Drake
Pooh-Bah
Reged: 10/09/02
Posts: 1293
Loc: Illinois
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Alright!! I was was there when Don was making this mirror and Dan Joyce's optical shop several years ago. It's good to see the scope has finally come together.
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Astronomy educator/Sidewalk astronomer
Owner of Astronomy Delight franchise
18 inch f4.42 Dob on eq platform w ST120 f/5 finder
12 inch Zhumell Dob modified by Brian Reed on eq platform
8 inch f/8 eq planetkiller
William Optics red 10th Anniversary 80mm FD
PST
24lb eyepiece box
Cernan Space Center astronomer
Member of Northwest Suburban Astronomers
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reiner
super member
Reged: 09/28/05
Posts: 100
Loc: Freiburg, Germany
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Dave, there must be a typo. A 23" with 3.8" thickness would be heavier than 60 pounds.
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Reiner
22" and 14" Dobs on EQ platforms
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dave b
Post Laureate
Reged: 05/10/05
Posts: 3534
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Quote:
Dave, there must be a typo. A 23" with 3.8" thickness would be heavier than 60 pounds.
that is true, more like 120 lbs. Maybe its 1.85" thick?
darren, did you see how thick the mirror was?
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dave bonandrini
30" f/5.2 Dobsonian
President of GCAC
Astromart Moderator
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johnnyha
Pooh-Bah
Reged: 11/12/06
Posts: 1109
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Kilos?
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Johnny
Spicewood, TX
Sherman Oaks, CA
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star drop
Guilty as Charged
Reged: 02/02/08
Posts: 16264
Loc: Snow Plop, WNY
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Very nice looking.
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Ted
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Darren Drake
Pooh-Bah
Reged: 10/09/02
Posts: 1293
Loc: Illinois
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It was radialy ribbed so it was partially hollow.
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Astronomy educator/Sidewalk astronomer
Owner of Astronomy Delight franchise
18 inch f4.42 Dob on eq platform w ST120 f/5 finder
12 inch Zhumell Dob modified by Brian Reed on eq platform
8 inch f/8 eq planetkiller
William Optics red 10th Anniversary 80mm FD
PST
24lb eyepiece box
Cernan Space Center astronomer
Member of Northwest Suburban Astronomers
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davidpitre
Carpal Tunnel
Reged: 05/10/05
Posts: 1824
Loc: Central Texas
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I'd be interested to hear how it performs.
My concern would be that the structure is not stiff enough.
The traditional secondary cage design (plywood rings joined to perpendicular aluminum tubing with inserts) does not seem to lend itself well to the mirror box for a big mirror. I mean it looks nice and light weight and all, just not rigid.
I'd love to give it a whirl, though. It might be fine.
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David
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Dennis Steele
vendor
Reged: 09/18/06
Posts: 26
Loc: Castro Valley, CA.
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The telescope is pretty rigid and stable. I think the "truss" hybrid adds considerable rigidity to the design. I had the pleasure of visiting with Don last week and we assembled his telescope together. The only "fix" needed to to secure the alt bearings to the upper ring of the mirror box. Otherwise, it's really a nice assembly. I do agree that "ultra light" is a stretch -- but when compared with the traditional dob design, I guess it's accurate!
Don did a beautiful job of finishing the wood with clear varnish. It shines.
Darren is right in that the mirror is "hallowed out" to reduce the overall weight. Still, I understand that it holds the figure very well. Apparently, the glass was originally from some sort of military or other DOD application, but I'm not sure.
Dennis 
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turtle86
professor emeritus
Reged: 10/09/06
Posts: 683
Loc: Red Sox Nation
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Looks like a great, great scope! 
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Jim Moscheck
Carpal Tunnel
Reged: 01/08/07
Posts: 1619
Loc: Under the SE Michigan lightdom...
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Very nice looking scope. 
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Jim Moscheck
Ford Amateur Astronomy Club
ATM truss dob
Stevens 14.5" f4.3
"A mind is like a parachute. It doesn't work if it's not open." - Frank Zappa
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APM America
Vendor - APM America
Reged: 11/07/05
Posts: 2775
Loc: Madison. NJ. USA
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Sweet!
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Morris Bagnall
Sales Manager
www.apmamerica.com
A whole room full of APM refractors......
Seymor Rosin F/4.5 Astrograph in the making
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ahlberto
sage
Reged: 09/06/08
Posts: 363
Loc: lisbon-portugal
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Simply beautifull!!Wath a scope...Thanks for sharing dave.
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http://www.facebook.com/home.php#/profile.php?id=1238507892&ref=nf
http://www.atalaia.org/index.php
CELESTRON C8
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TimD
scholastic sledgehammer
Reged: 02/16/05
Posts: 900
Loc: CA USA
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NICE indeed!
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Takahashi TSC 225
WO Megrez 102
Meade ETX 90, ETX 125
Meade LX90
Classic Orange tube C14, C90, C5+
Etc,Etc,Etc!!
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