Moki
super member
Reged: 11/06/05
Posts: 358
Loc: Dallas, GA
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Quote:
Quote:
8 in. F7 finished today. First light tonight!
DANG! that is cool.
What kind, if any, flexure do you experience?
Is that tube ring rotatable?
I luv it....
Great job, very well executed. 
Rob
Gold Mtn Observing Center
Thank you!
The tube flexes none at all. It's very stiff and vibration free. I'm still working on the mount. It's from an old Celestron SCT and is a bit loose around the axes. This weekend I'm going to disassemble, clean, regrease, and see if I can tighten it up some. It tracks well, though.
The tube rotates in the center saddle. It holds direction reasonably well.
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"In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual." Galileo
12.5" F5.3 Dob on EQ platform
8" F7 planetary Dob / EQ Platform
Current ATM projects:
Xtal-Controlled EQ platform motor drive
8" F6 Dob for club
Motorized focus for planetary
10" F6 Ultralight PushTo
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rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 6190
Loc: Bremerton Washington
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Quote:
Quote:
Quote:
8 in. F7 finished today. First light tonight!
DANG! that is cool.
What kind, if any, flexure do you experience?
Is that tube ring rotatable?
I luv it....
Great job, very well executed.
Rob
Gold Mtn Observing Center
Thank you!
The tube flexes none at all. It's very stiff and vibration free. I'm still working on the mount. It's from an old Celestron SCT and is a bit loose around the axes. This weekend I'm going to disassemble, clean, regrease, and see if I can tighten it up some. It tracks well, though.
The tube rotates in the center saddle. It holds direction reasonably well.
Super work!
I'd like something like that for my Observing Center.
I had contemplated building one myself.
Luv the color too. 
Rob
Gold Mtn Observing Center
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www.goldmtobservingcenter.com
Providing a great place for amateur astronomers, and ATM's to come and enjoy their hobby.
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philipdo
sage
Reged: 12/06/06
Posts: 205
Loc: Flanders, Belgium, Europe
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Thanks Rob!
the ETX is not always mounted on the counterweight arm, only for public starviewing activities. On March 3rd we have a total lunar eclipse over here. It is also our national 'astronomy day' in Belgium. For this event I will mount the ETX and use it for pictures of the eclipse while keeping the schief free for visual observing. We will set up for the event with our local club, about 15 scopes on the field and we're expecting 400-600 visitors spread over two days.
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-philip doutreligne
-ETX 90
-Kutter Schiefspiegler 200/4000
-Orion Atlas mount
http://users.telenet.be/philipdo
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rwiederrich
Goldfinger
Reged: 11/17/05
Posts: 6190
Loc: Bremerton Washington
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Philip,
Great scope. Man I wish we had a total over here.
Do post some images if you can, and the scope field... 
Rob
Gold Mtn Observing Center
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www.goldmtobservingcenter.com
Providing a great place for amateur astronomers, and ATM's to come and enjoy their hobby.
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lukejames
professor emeritus
Reged: 01/11/07
Posts: 605
Loc: England, nottingham
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there all very cool guys =D
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Luke James, Aged 13, England.
Meade Etx 80
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philipdo
sage
Reged: 12/06/06
Posts: 205
Loc: Flanders, Belgium, Europe
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Quote:
Philip,
Do post some images if you can, and the scope field...
Rob
Gold Mtn Observing Center
will do.
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-philip doutreligne
-ETX 90
-Kutter Schiefspiegler 200/4000
-Orion Atlas mount
http://users.telenet.be/philipdo
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bongk
member
Reged: 09/01/06
Posts: 10
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Here is my recently completed 12.5" F-5 obsession style truss dob.
The mirror is "hubbleoptics" off of E-Bay. I haven't had enough clear nights to really gauge the quality. So far I have been satisfied for what I paid but not overwhelmed. I sold my LX200 and am just finishing an 8" dob (you can see the coopered OTA in the background) so soon I'll have something to compare it side by side to.
Overall I probably spent about $650, half of which was the primary.
Interesting aspects:
I started with the six-point triangular plywood flotation cell, but I reversed it so that its a triangular hole in a square board. This gave me more opening for cooling, seemed more rigid, and allows for finer collimation adjustments.
I made the spider from various nuts, bolts, and aluminum strip and angle. I'm pretty happy with it. I had a hard time finding small cheap compression springs, but I had a bunch of rubber castration rings from the local Farm&Fleet. I stacked a few of these on a bolt and it worked just like a compression spring.
All the wood is scrap from my basement. Saved some money here and it still turned out nice. Instead of gluing plywood sheets for the altitude bearings, I cut the half circles out of a 2x10.
The truss poles are only 1/2" diameter (I got a good deal). I worried that this was the corner I cut too much, but its surprisingly rigid. Holds great collimation at any angle and I dont see any flex when I move it around.
My mirror cover is inside the mirror box below the truss tube clamps, so I was able to mount half the truss clamps inside the box.
I had to borrow my dad's router for the rings and bearings, otherwise all I used were a drill, a table saw, and hand tools. I've picked up a used Radial Arm Saw since then and think I could have done a nicer job on some of the cuts with it instead of the table saw.
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rboe
Numbfinger
Reged: 03/16/02
Posts: 40419
Loc: Phx, AZ
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Not bad at all. I think most of us build a second or third scope because of we learned doing the first. 
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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mattyfatz
Pooh-Bah
Reged: 12/27/06
Posts: 1188
Loc: R E N O
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This is the best thread on this site. These scopes are all inspirations to those of us who are about to embark on a project.
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*****MATTY******
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Art Bianconi
Post Laureate
Reged: 03/06/06
Posts: 4659
Loc: Delaware River Valley, New Jer...
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Bongk wrote: ". . . think I could have done a nicer job. . "
I still have that same pesky voice in the back of my head, after all these years.
No matter what you tell yourself about how nice a job you did. No matter how nice a job WE tell you, you did, that voice will always be there saying "Yes but they don't know about the time you messed up the thingobritz?"
You did a nice job. A truss that is really a truss. A coopered OTA (a difficult job with any saw!) and miracle of miracles: a spotlessly clean floor!!
Congrats on all three!
Art
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“Everything is on its way to somewhere. . . . . everything!"
____________________ George Malley (John Travolta)
________________________ "Phenomenon"
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Galaxyhunter
scholastic sledgehammer
Reged: 01/02/06
Posts: 931
Loc: Northern Illinois
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I'm a little late catching this thread, and this pic is in the refractor forum. But seeing that I did build it, here is my humble toy.
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Carl
Hawkeye Observatory
Observatory - "Hawkeye"
Scope - 18"f4.5 on a GEM
Drive - Sitech Technology
DSC - Sky Commander
Planetarium - MegaStar
Camera - ST2000XM - AO-8
Desire - comes & goes
Talent - ZERO, NONE, NADA (But I can Wish)
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Jeremy@za
professor emeritus
Reged: 02/28/05
Posts: 704
Loc: Cape Town, South Africa. 33 56...
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Carl - please tell me that isn't made out of 44 gallon drums 
Looks really nice! Is that the 18" scope from your sig?
J
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JohnG
sage
Reged: 12/16/06
Posts: 357
Loc: Wake Village, Texas - East Tex...
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Gee, these are GREAT pictures of telescopes. Just looking at them is inspiring and filled with tons of wonderful ideas for design.
Carl, your scope is a home-built gem, especially that pillow block mount. I've been considering either building one or buying one from Opti-Craft. Did you make yours?
John Gerrald
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John Gerrald
Unitron Model 142
8 Inch f/7 Custom Assembled
8 Inch Celestron/Vixen f/5 Newtonian
6 inch Celestron/Vixen f/5 Newtonian
8 Inch f/2.9 Sky Research Newtonian
Celestron Polaris Equatorial Mount
Celestron Super Polaris Equatorial Mount
Celestron 11 x 80 Comet Hunter Binocuars
Bausch & Lomb 7 x 50 Binoculars
A few vintage eyepieces
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rboe
Numbfinger
Reged: 03/16/02
Posts: 40419
Loc: Phx, AZ
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So Carl; just how mobile is that scope? 
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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Terry1229
super member
Reged: 04/16/06
Posts: 144
Loc: North, Idaho
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My 6' F8
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Terry:
A 6" f8 dob with 14mm Anteres eyepiece
Wixey
Homemade EQ & stepper
QC pro4000
spc900
homemade ele. focuser
New [used] Meade 8" sc ota
New [used]] CG5
Edited by Terry1229 (02/26/07 02:18 PM)
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Brian Reed
Vendor (Round Table Platforms)
Reged: 10/29/04
Posts: 378
Loc: North East Illinois
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Wow, lots of wood working skills there. I like your moon cut-outs
I see you have a wixey angle gauge. I just got mine last week for use around the shop. How well does it work for an altitude angle meter -- Do you have to wait very long for it to settle down to get an accurate reading?
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Brian
10-F5.6
8-F7
http://www.roundtableplatforms.com
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Terry1229
super member
Reged: 04/16/06
Posts: 144
Loc: North, Idaho
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I have not had a change to use it outside yet.
But in the basement, it seems to be a little touchy. Maybe because of all the metal and wireing around.
Someday the sky will be clear again! Then we can give it a good try....
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Terry:
A 6" f8 dob with 14mm Anteres eyepiece
Wixey
Homemade EQ & stepper
QC pro4000
spc900
homemade ele. focuser
New [used] Meade 8" sc ota
New [used]] CG5
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Bill Kocken
super member
Reged: 08/07/04
Posts: 163
Loc: Coon Rapids, MN
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Here is a 16"f4.5 Meade Starfinder which has been mostly rebuilt into an Obsession-style truss scope. I say "mostly" because you can see that the rocker box is still the original Meade part. I merely cut it down to fit the new 22" diameter altitude bearings. Don't worry, I'll build a proper plywood base later this spring.
Bill Kocken
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16"F4.5 Homebuilt Truss Dob
2 - 8"F6 Homebuilt dobs
Member, Minnesota Astronomical Society
Edited by Bill Kocken (02/26/07 05:32 PM)
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Galaxyhunter
scholastic sledgehammer
Reged: 01/02/06
Posts: 931
Loc: Northern Illinois
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Quote:
Carl - please tell me that isn't made out of 44 gallon drums
Jeremy, No not 44 gallon, only 30 gallon.
Quote:
I've been considering either building one or buying one from Opti-Craft. Did you make yours?
John, Yes, I did the complete scope, less grinding the mirror.
Quote:
So Carl; just how mobile is that scope?
Ron, before I built my observatory last spring, This scope was very mobil.
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Carl
Hawkeye Observatory
Observatory - "Hawkeye"
Scope - 18"f4.5 on a GEM
Drive - Sitech Technology
DSC - Sky Commander
Planetarium - MegaStar
Camera - ST2000XM - AO-8
Desire - comes & goes
Talent - ZERO, NONE, NADA (But I can Wish)
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Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2276
Loc: Courtice, Ontario
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Here's my first ATM project. It's a 5.1" f/5 travelscope. It's the first of many to be sure as I'm hooked now!
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Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
 My house.
 DRAACO
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