Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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I'm a great fan of Rita Hayworth. She was a classic, and hopefully, this project will recreate a classic. What we got here, is a 6" long FL newt. Mark Harry was kind enough to take on the task of finishing the mirror. It's not coated yet, hopefully it'll get done sometime this month. (Company recommendations?) It turned out with a FL of 52.44", hitting what I was shooting for (F8-F9) dead on. HERE is the story of the mirror, as told by Mark.
I wanted something a bit unusual, so here is -part- of the story in pictures.
I started laying out the bulkheads on 8"x8" birch ply. 4 3/8" and 4 1/2"
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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I decided the only proper way to make the hexagons was a jig.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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I lightly glued all the bulkheads together, then using another jig, cut the slots for the stringers.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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I don't have any shots of cutting the centers out. This is where Rita got it's name-it was a B***H! Here, I'm starting assembly of the bulkheads and stringers. The stringers are 1/8" oak, that I cut from an oak board.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Here is a shot of the almost completed assembly.
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Hubert
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www.smoggybottom.org
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veebs2
special label
Reged: 03/13/07
Posts: 287
Loc: DeKalb, IL
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Looks good so far!! 
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Paul
Zhumell 10" (My Mistress - name given by my wife)
Hyperions - 5mm, 13mm and 24mm
Stratus - 8mm and 17mm
Howie Glatter 2"-1 1/4" Holograpic w/ Barlow
Lumicon OIII Filter
Telrad
DeKalb, IL
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Once the cage was completed, I taped off major glue joints and painted the assembly flat black.
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Hubert
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www.smoggybottom.org
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Sky Captain
Metal Whisperer
Reged: 11/07/04
Posts: 7190
Loc: Issaquah, WA.
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Nice start to the project Hubert! 
Looks like your wood working skills are up to the task.
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Equipment Overload!
Kerry
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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The flat black paint was pretty reflective. So I glued black felt to each bulkhead, then started assembly of the skin. Each piece was cut at a 45 degree angle, the fitted in place and glue joints marked. Then black felt strips were glued to each piece, and then glued to the bulkheads.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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The corners were fiberglassed, 1" wide tape.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Humidity defense: Everything got a preliminary coat of primer. Note the duct tape seal inside the tube. I try to seal both ends for most of the sanding to keep dust out of the interior.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Well, one can dream a bit when you're doing this, can't you?
(this is all for today)
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Hubert
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www.smoggybottom.org
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Achernar
Postmaster
Reged: 02/25/06
Posts: 5024
Loc: Mobile, Alabama, USA
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This is a very clever jig you came up with. Especially since it allows for the creation of identical, multiple octagonal parts without guesswork. I presume you cut out the center with a drill press and a fly cutter attachment. That was how I made the end caps for my 6-inch Dob, whose hexagonal tube is made of Cherry edge glued together.
Taras
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15-inch F/4.5 Dob under construction
10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
A whole bunch of eyepieces, filters and other accessories....
Two curious cats
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Mark Harry
Post Laureate
Reged: 09/05/05
Posts: 3124
Loc: Northeast
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Doggone, Hubert; How'd you get the wife to allow the use of her dining table, and granite countertop!!!
Mark
BTW, nice work!
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So many projects, so little time!
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Stefan Rostyne
Pooh-Bah
Reged: 10/19/04
Posts: 1009
Loc: Assenede, Belgium
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I like it!
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Stefan Van de Rostijne
4.5" F4.5 newt 5°widefield/finderscope
8" f/5.6 travel dob
old 12.5" F5 dob (used to look better...)
30 cm f/30 Classic Cassegrain (polishing primary)
23" f/4 dob project
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Darenwh
Pooh-Bah
Reged: 05/11/06
Posts: 1224
Loc: Covington, GA
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That looks like it is turning out great. Very impressive work. Was your wife out of the house when you used the table and countertops? Doing something like that for me just might get me killed.
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Daren
Covington, GA
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JohnH
professor emeritus
Reged: 10/04/05
Posts: 734
Loc: vancouver near the wilds of B...
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You didn't show the cutting of the circles out. I made two cases for scopes where I cut out circles for the cradle inside. The first time, I mounted the 1/2" baltic in a lathe and used a parting tool. It needed so much careful sanding, I nearly quit. The second time, I had a jigsaw but I needed to do it twice, as I had little experience using one.
I can't begin to guess how difficult it was to place and glue the 8 splines. You could have gone to 1/4" but that would require the always expensive and difficult to use dado blade. With that much support, you could get away with just using a sheet of veneer. Think of it, walnut burl veneer like a Rolls-Royce dashboard.
How did you attach the fiberglass tape?
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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I'll see if I can answer some questions. Yes the plan was to use a fly cutter in a drill press to cut the centers out, however, due to various circumstances, I mostly used a scroll saw.
The 8 splines were overkill, I think you coulda stood on the thing after it was together. Placing them was not bad, once I got the first couple in. I held them in place temporarily with pieces of masking tape.
I wanted to make the skin from 3/32" or maybe even smaller but it was just not available anywhere in the Houston area in the quantities I needed. (Lotsa places had 1 or 2 pieces....) As for walnut veneer, have you priced that stuff lately?????
Edited to add: The fiberglassing is ordinary marine epoxy. I'll also be using the epoxy with "micro balloons" on the rear splines. I've been wanted to try that stuff.
I have a very understanding wife.... It's an old table, and I was really careful to cover the countertop when necessary.... 
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Hubert
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www.smoggybottom.org
Edited by Pedestal (09/02/09 07:36 PM)
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3453
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Nice job!
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Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
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plyscope
sage
Reged: 11/23/06
Posts: 327
Loc: Perth, West Australia
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Very nice work Hubert. I have a soft spot for octagonal tubes and /5 BMW motorcycles.
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Andy
6" f15 refractor
90mm f16.7 refractor
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JohnH
professor emeritus
Reged: 10/04/05
Posts: 734
Loc: vancouver near the wilds of B...
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Quote:
The 8 splines were overkill, I think you coulda stood on the thing after it was together. Placing them was not bad, once I got the first couple in. I held them in place temporarily with pieces of masking tape.
I wanted to make the skin from 3/32" or maybe even smaller but it was just not available anywhere in the Houston area in the quantities I needed. (Lotsa places had 1 or 2 pieces....) As for walnut veneer, have you priced that stuff lately?????
I haven't priced it lately, I just have friends who have friends.....etc etc. I belong to one of those groups of people into "wood porn". WE buy piles of materials and simply stockpile it. We go out and move it around every once and awhile or just to look at it.
Currently I am doing the same with pyrex blanks. Tragic, really.
As for walnut veneer, you are correct about the price. I do have an ace up my sleeve. A friend who moved to CA bought a piece of property with 25+ acres of walnut trees. He lives in one of those areas where the police will pull you over if you have wood like that in the back of your vehicle to see if you can account for it. He says if I come down there, I can have my choice of a tree.
Getting it home might be a problem as Hertz doesn't rent 5 tom flatdecks with cranes.
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Owen
professor emeritus
Reged: 06/21/07
Posts: 514
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Lets see if I can answer a few back 
A router with a circle cutter jig would have made very short work of the center circles (and the circle jigs are available to diy as easy as a very easy thing), which would have sped up the process...
The veneer need only have been used for the top and bottom sections of the OTA, the remainder would be stiff enough without the skin.
To save the expense of a dado blade all you needed to do was to slightly offset your jig - the kerf is around 3mm on a good blade (up to 6 on a monster carbide job), and that would have given you a wider stringer slot (infact if you performed the offest twice (so four passes), then you could get quite a wide groove ....
Have fun - this is an interesting build, and I'm looking forward to the developments.
Owen
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tim53
Pooh-Bah
Reged: 12/17/04
Posts: 1440
Loc: Highland Park, CA
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I like the jig you used for making the hexagons. I may try to rig up something like that next time I make a 9-sided tube with bulkheads. But these days I do that for refractors only.
I made my 8" f/6 Springfield's tube using bulkheads similar to the way you did it, though instead of the stringers, I routed grooves into the 1/4" plywood sides for them to live in. That was 1981. For years, I couldn't figure out why the planetary views I used to get with that primary were seldom up to snuff - I thought I might have selected a bad secondary mirror when I built the scope.
But when I had a similar problem with my 12.5" Cassegrain, I realized it was the bulkheads/baffles that were causing the poor definition. They were acting like stair steps for the tube currents to get into the light path, rather than hugging the walls of the tube.
The new (and final) tube for the Cass, I made with 1/4" Teak plywood with longitudinal corners made from poplar (of all woods!, but I selected samples that look pretty good with the teak), and I made the tube ID big enough (like 15") that tube currents (and glare) aren't a problem anymore.
-Tim.
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"We`re just waiting looking skyward as the days come down.
Someone promised there`d be answers, if we stayed around."
-Orchestral Maneuvers in the Dark, "The Romance of the Telescope"
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Here is a shot of the first (of many, I suspect) coats of "Sunrise Red". I put a reinforcing band around the bottom, where the mirror cell will mount. Boy, I hope I got all the holes in the right place!
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Here is a shot of the final (I think!) version of the mirror mount. Sent the mirror off to Spectrum for coating.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Shot 1 of the mount cradle. The unpainted portions will be felt covered when the paint is done.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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The cradle will have a Vixen style rail. I think I'm going to use a "strap system" to hold the tube in the cradle. Still contemplating that one.
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Hubert
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www.smoggybottom.org
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polaraligned
sage
Reged: 12/26/08
Posts: 228
Loc: P. R. of New Jersey
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Beautiful work.
That red is the same color as the first telescope I built. It was a square wood tube. Somehow I wish I still had it.
Look forward to seeing the completed scope.
Scott
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Things are progressing. Got the mirror back from Spectrum. Here it is mounted in the cell.
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Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Making progress on the mount. Thought I had the counterweight situation figured out, until I priced lead shot. At $4 a pound, I'll figure something else out. For a sense of scale. The turned plate is 8" in dia, the dec shaft is 1".
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Hubert
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www.smoggybottom.org
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droid
rocketman
Reged: 08/29/04
Posts: 4034
Loc: ohio
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updates????????? I was holding my breathe waiting for the final pics, but I ran out of air.. 
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102mm Celestron C102HD
Tasco 7TE5 60mm Classic
Tasco 9TE5 60mm Classic
Celestron Ultima 2000 SCT
Remains of an 8 inch dob
Celestron Comet catcher(orange tube)
1960 Edscorp Space Conquerer 6inch f/8
10x50 Bushnell Binoculars.
11T 4.5 inch Tasco reflector Lunograsso?
60mm Telescope Club
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Don W
Postmaster
Reged: 05/19/03
Posts: 14620
Loc: Wisconsin, USA
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I think you'll find it here:
First Light
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Don Wyman
Obsession 18" f/4.5 #1166
W/Argo Navis DSC and Torus Primary
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3850
Loc: Smoggy Bottom, Baytown,Texas
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Sorry-I forgot about this thread. I also decided it wasn't Rita anymore, it was the Red $$$ch 
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Hubert
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www.smoggybottom.org
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