Chris Erickson
Carpal Tunnel
   
Reged: 05/08/06
Loc: Waikoloa Village, Hawaii
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Re: Why not a cylindrical observatory?
[Re: drollere]
#5067926 - 02/11/12 10:06 PM
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yeah, i agree with erickson's list of considerations. and i'd suggest they lead to one conclusion. once you plug in all the thermal and operation issues, a dome or anything that rotates simply doesn't make sense without the single overriding criterion of thermal shelter in extremely cold conditions.
yes, domes or modified cylinders are used on the "big boy" observatories. but part of that is an engineering solution for a really big mobile structure.
i can't look at the models here without feeling that the modified cylinder is fundamentally an *esthetic* and conceptual solution to the shelter problem in a small instrument observatory. and that usually means the practical operation and maintenance issues, not to mention the management of thermal discharge through the "chimney", are going to be more of a hassle than you anticipate.
whatever you do, good luck.
Just for general information, adding some square louvers and/or a squirrel-cage fan is fairly easy and inexpensive to do to just about any observatory.
Of course the best solution is to generate as little heat as possible in the observatory in the first place.
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netwolf
super member
   
Reged: 09/03/05
Loc: NSW, Australia
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Re: Why not a cylindrical observatory?
[Re: BPO]
#5664942 - 02/06/13 10:33 AM
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Mi 3, your design is identical to this one made by Shevill Mathers details on his page.
http://www.apstas.com/astrotas/mathers/smathers.htm
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RobertED
Carpal Tunnel
   
Reged: 07/11/03
Loc: Johnston, RI
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Re: Why not a cylindrical observatory?
[Re: netwolf]
#5664958 - 02/06/13 10:43 AM Attachment (30 downloads)
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May I present to you...Seagrave Memorial Observatory, North Scituate, RI. Home of an 8" Alvan Clark refractor.
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RobertED
Carpal Tunnel
   
Reged: 07/11/03
Loc: Johnston, RI
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Re: Why not a cylindrical observatory?
[Re: RobertED]
#5664960 - 02/06/13 10:44 AM Attachment (27 downloads)
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Closer view of circular dome.....
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RobertED
Carpal Tunnel
   
Reged: 07/11/03
Loc: Johnston, RI
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Re: Why not a cylindrical observatory?
[Re: RobertED]
#5664962 - 02/06/13 10:45 AM Attachment (22 downloads)
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...and a third....
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dobsoscope
sage
   
Reged: 05/24/06
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Re: Why not a cylindrical observatory?
[Re: RobertED]
#5665026 - 02/06/13 11:23 AM
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Just make sure you do not escort anyone out of the second level door !
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RobertED
Carpal Tunnel
   
Reged: 07/11/03
Loc: Johnston, RI
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Re: Why not a cylindrical observatory?
[Re: dobsoscope]
#5665087 - 02/06/13 11:57 AM
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They used to have a nice staircase to escort folks down during the "Halley's Comet Crunch"....but have since been removed to keep it looking as it did originally .
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CharlesW
sage
Reged: 11/02/12
Loc: Chula Vista & Indio, CA
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Re: Why not a cylindrical observatory?
[Re: RobertED]
#5666156 - 02/06/13 10:25 PM
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Maybe I'm over simplifying this but it seems to me that early astronomers adopted a hemispherical dome because they needed an enormous roof structure, unsupported in the middle. Subsequent observatory designers probably stuck to tradition. If the architect of the Palomar Observatoy had access to modern lightweight construction materials, that structure might look quite different. Even with my extremely modest construction skills, it would seem to me to be vastly easier to build a small backyard cylinder.
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mikey cee
Postmaster
   
Reged: 01/18/07
Loc: bellevue ne.
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Re: Why not a cylindrical observatory?
[Re: CharlesW]
#5666203 - 02/06/13 10:58 PM
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The biggest problem I would have with a cylindrical observatory is the viewing circle. Any desk, chair, accessories cart or cabinet is always smack dab in the way. I'd be forever stumbling over or backing into something in the road. Mike
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RobertED
Carpal Tunnel
   
Reged: 07/11/03
Loc: Johnston, RI
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Re: Why not a cylindrical observatory?
[Re: mikey cee]
#5666493 - 02/07/13 06:00 AM
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I'm even thinking, if memory serves me, that the clubmembers have to occasionally clear heavy snow off the flat roof surface!!(re: Seagrave Obs.).....
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timwetherell
sage
   
Reged: 09/03/10
Loc: A Land Down Under
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Re: Why not a cylindrical observatory?
[Re: Chris Erickson]
#5667916 - 02/07/13 09:43 PM
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It does help Those are some very good pointers for any observatory cylindrical or not!
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timwetherell
sage
   
Reged: 09/03/10
Loc: A Land Down Under
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Re: Why not a cylindrical observatory?
[Re: CharlesW]
#5667921 - 02/07/13 09:47 PM
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Yes. I believe the housing for the GMT will essentially be a cylinder
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SkipW
super member
Reged: 02/03/11
Loc: Oklahoma, USA
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Re: Why not a cylindrical observatory?
[Re: timwetherell]
#5668182 - 02/08/13 12:23 AM Attachment (16 downloads)
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Here's the "Grain Bin Dome" at the National Solar Observatory in Sunspot, NM. It's the earliest instrument shelter at the facility, built from a modified mail-ordered Sears & Roebuck Corrugated Grain Bin.
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SkipW
super member
Reged: 02/03/11
Loc: Oklahoma, USA
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Re: Why not a cylindrical observatory?
[Re: SkipW]
#5668188 - 02/08/13 12:27 AM Attachment (10 downloads)
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Drive mechanism for the Grain Bin Dome at NSO.
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Starhawk
Post Laureate
Reged: 09/16/08
Loc: Tucson, Arizona
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Re: Why not a cylindrical observatory?
[Re: SkipW]
#5670656 - 02/09/13 12:34 PM
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There's a certain degree of beauty the cylinders lack. Consider a square building with either a peaked roof with a shutter or a single slope roof where the whole thing rotated. It could set on the ground and just be a rotatable building.
-Rich
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rimcrazy
member
Reged: 03/03/12
Loc: Overgaard, AZ
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Re: Why not a cylindrical observatory?
[Re: Starhawk]
#5671938 - 02/10/13 08:05 AM
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Here in Arizona two of the most historically famous observatories are cylinders.
The Clark dome houses the Clark refactor that Percival Lowell used in founding the Lowell Observatory.
And Clyde Tombaugh used the telescope in this building to discover Pluto.
I would say that there are a few pretty famous cylindrical observatories around.
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Kaizu
sage
Reged: 08/17/07
Loc: Finland
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Re: Why not a cylindrical observatory?
[Re: Escher]
#5672043 - 02/10/13 09:48 AM
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I like your second link...
Here is a simple solution for the track... Using an octagon of 2X12 or similar pieces, you can inscribe a circular track.... Instead of trying to make a perfectly circular piece.
I would use two courses rotated a bit so that their seams are not inline - to give additional strength.. Then put rollers on the bottom of the octagon shaped "cylinder" to rotate it...
I built mine almost as by your sketch. Click the first image and you see how I built it. The "dome" is made of aluminium sheets which are fixed and sealed on a wooden sceleton. The Cityobservatory has resisted wind, rain and snow few yeas. Inside there is a 10" TAL250K or a 10" Newton astrograph.
Kaizu
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