denise41
sage
Reged: 01/31/05
Posts: 312
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In 1994 I bought my first serious telescope, a Meade Starfinder 8in on an equatorial mount. The scope had good optics but poor mechanics and it was too heavy and cumbersome to easily move very often so I decided to build a temporary observatory for it. It is now 11 years later and the observatory which was meant to last only a couple of years is still going strong. This rotating observatory has withstood sustained winds of 60 knots with gusts to over 80 knots more than once and the interior has remained dry and the scope, well protected. The vertical and horizontal hatches allow 1hr exposures before the observatory needs to be rotated, which I can easily do by myself. My plans to build a permanent observatory are now on hold as long as this little green thing keeps serving me so well. The diameter is just over 10 feet and when the dust skirt is attached to the circumference just above the exterior plywood reinforcing ring, the interior remains relatively free from dust or debris which might otherwise blow in under the walls of the observatory. The joints of the frame are unglued so they may flex freely and the roof may be forced into a slight peak by using a removeable center pole from the floor to the pvc pipe which spans the interior of the roof. I designed this observatory in about an hour and it was constructed on my 12ft deep front porch, the limiting size of the design, in 2days and then rolled up the hill to the pad. Here are some pictures.
Denise Libby
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denise41
sage
Reged: 01/31/05
Posts: 312
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This picture shows the door which was cut in three places from the middle of one of the panels and uses the flexibility of the material itself as the hinge. The open horizontal hatch can be seen extending past the roof line.
Denise Libby
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denise41
sage
Reged: 01/31/05
Posts: 312
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Since the slab is absolutely level a ring dam was required to keep the floor dry during heavy rains.
Denise Libby
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denise41
sage
Reged: 01/31/05
Posts: 312
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To keep the observatory on the pad when rotating a guide ring was necessary.
Denise Libby
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denise41
sage
Reged: 01/31/05
Posts: 312
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To reduce friction when rotating the observatory a vinyl hose was split and attached to the guide ring.
Denise Libby
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photonovore
Moonatic
Reged: 12/24/04
Posts: 2792
Loc: tacoma wa
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that's pretty neat allright, but one question; the roof looks flat, even somewhat dished? If so how do you keep rain from pooling there and collapsing the roof?
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Mardi
4" achromat, ETX-70, 8"cat.
Whitepeak Lunar Observatory Website
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denise41
sage
Reged: 01/31/05
Posts: 312
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Dear Photonovore;
The roof is designed to flex and can be forced into a slight peak with a center pole from the floor to the transverse roof support. It works like a charm and I've never had rain in the observatory in 11 years no matter how much rain we've had. The roof has even had 4in of snow on it and even though is was not designed to carry a snow load, it sufferd no leaks or damage.
Denise Libby
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tcraig
sage
Reged: 02/19/05
Posts: 439
Loc: Northern Indiana
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Very neat idea. Do you have anything other that the guide ring to help hold it in place and or down during a storm?
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KC9RRV
LXD75-SN10
LPI
300D
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denise41
sage
Reged: 01/31/05
Posts: 312
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Here, my husband, who performed the remodeling work on the observatory, is demonstrating the sliding vertical hatch.
Denise Libby
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denise41
sage
Reged: 01/31/05
Posts: 312
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Dear Tcraig;
In four equally spaced places on the top ring of the observatory are eye bolts from which a rope is attached and at the other end of the rope is a snap shackle that clips into the welded eye of a 24in long 1/2 in rod imbedded in the corner of the slab. This makes the observatory very stable in even the strongest winds and is easily returned to servicability after the storm has passed. In most cases the use of these restraints is not necessary in winds of less than 35knots.
Denise Libby
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dgs©
Postmaster
Reged: 03/29/04
Posts: 15091
Loc: West Monroe, Louisiana
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Simplicity and clever use of common materials... brings to mind John Dobson himself.
Good job. Glad you have been able to enjoy it so long. PVC tends to get brittle after long exposure to UV light from the sun, but the few exposed bits of yours seem to be holding up well.
Is the roof attached to the walls with any sort of fasteners?
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- david
8"Ø Newtonian on SVP, Moonlite CR2, Telrad
PST Oberwerk Ultra 15x70 Orion Ultraview 10×50
Hand-me-down Sears Refractor (Discoverer) 60mm×900mm
"What we have done for ourselves alone dies with us; what we have done for others and the world, remains and is immortal." --Albert Pike
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denise41
sage
Reged: 01/31/05
Posts: 312
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Dear David;
Thanks for the very nice compliment. The roof is attached with 3in, #10, pan head machine screws which pass through rubber gasket stainless washers, at 10 inch intervals around the roof. The screws are secured with wing nuts inside the observatory. Fortunately, none of the structrual pvc components are exposed to sunlight.
Denise Libby
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Scott Beith
SRF
Reged: 11/26/03
Posts: 42898
Loc: Frederick, MD
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That is pretty cool!. 
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   SLAP Observer --- TMB130SS, SV102V(LOMO Lens), SV80ED Deluxe
"The only thing necessary for the triumph of evil is for good men to do nothing." -- Edmund Burke.
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell
"The measure of a man’s greatness is not determined by what he accomplishes for himself, but by what he accomplishes for others.” -- Some Bald Guy
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rboe
Reged: 03/16/02
Posts: 63466
Loc: Phx, AZ
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I'm still shaking my head. But nothing succeeds like success. 
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Ron
NS11GPS
Pronto
16" dob
127mm F9 Surplus Shed/Crawmach kit scope
Coronado SolarMax 40 on a Celestron 102 Wide Field
Best of ATM
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Anonymous
Unregistered
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Quote:
I'm still shaking my head. But nothing succeeds like success.
Good job Denise; sorta like mathematically a bumble bee should not be able to fly 
The fact that it *looks* like it should not work but yet it does work is a tribute to a sound design. But I too am still shaking my head!
Bill
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celestial_search
Carpal Tunnel
Reged: 11/18/04
Posts: 2569
Loc: Iowa, USA
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Unique and functional.
It grows on you. Nice. 
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Frank
C-11 XLT
8" f/6 Newt on GEM
Tak FS-102II
SV 80L Triplet APO
EQ-6 Mount on pier in backyard observatory (EQMOD)
CG-5 AS (GOTO)
SBIG ST-5C CCD and Canon Rebel XSI
SSAG
Oberwerk 15X70s and Pentax 10X21s
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denise41
sage
Reged: 01/31/05
Posts: 312
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Dear Scott,Ron, Bill and Frank;
The idea of the rotating observatory is not new. It is my understanding that on Manua Kea there are two versions. The James Clerk Maxwell observatory and the Subaru. Each is sightly different with the main difference being the hatch arrangement and of course in the Subaru, only the upper portion of the observatory rotates. It seems, that by serendipity, I stumbled across a design that others have found sucessful also. Of course the fact that mine only cost $250 as opposed to the millions the other two cost makes mine more practical for my purposes.Ha ha!
Oh! and I don't have to remember where I parked my car.
Denise Libby
Edited by denise41 (08/17/05 12:18 AM)
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rboe
Reged: 03/16/02
Posts: 63466
Loc: Phx, AZ
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Keep working at it - maybe you'll get a chance to build one in Hawaii too. 
--------------------
Ron
NS11GPS
Pronto
16" dob
127mm F9 Surplus Shed/Crawmach kit scope
Coronado SolarMax 40 on a Celestron 102 Wide Field
Best of ATM
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denise41
sage
Reged: 01/31/05
Posts: 312
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Dear Ron;
From your lips to Gods ear.
Denise Libby
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Anonymous
Unregistered
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Still a good design; only a moron would clone a bad design
How hard is it to rotate? Could the rotation be acomplished (within reasonable means) via electric motor?
Thanks in advance,
Bill
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