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When it's windy, what observatory type is best.


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I am at the plan and save stage for my observatory and having been blown to bits in the wind today, have been thinking.

What is the best sheltered observatory.

I sit on a hill (ok bump, it's in Essex), but when any draft blows my observing is spoiled by the scope shakes from the wind.

So what observatory will be best shelter?

 

Edited by Alan White
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Wot - got no skills?  Hemispherical DIY domes every time for wind, LP and dew protection for scopes and user !  And it can be done with cylindrical sheet panels Nytecam 

Looking well used.... My mate found some (reject) double glazed windows from the hi-speed train - I fitted a couple into the Octodome.... You can see the double door on one side of the Octod

Well, it has to be a dome - minimum exposure to wind and the dome will never lift off in a storm - my Pulsar Observatories dome has survived several storms without incident and zero water ingress.

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So what observatory will be best shelter?

Well, it has to be a dome - minimum exposure to wind and the dome will never lift off in a storm - my Pulsar Observatories dome has survived several storms without incident and zero water ingress.

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I would love a dome, despite its arousal to  some folks suspicion, it would be  more than sufficient, and I have considered many  other options and will no doubt try a few, but the best wind break I had so far is my Dob tent!.....this one,  http://www.gooutdoors.co.uk/hi-gear-utility-tent-p148806

It would have been better  for me all black, like the base, but a throw over cover masks most of my street lighting. There is room for me, the chair and Dob mount. Not sure how a taller system would cope?

Edited by Charic
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9 minutes ago, Alan White said:

I would love a dome as well, but I am not sure my pockets hold enough wonga.

That's the 'plan and save' stage then! :icon_biggrin: Pockets holding wonga? Hmmmmm, there's no wonga left in my pocket so you may be right there. However, a dome is the answer to windy conditions.

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A cheaper alternative to a hemispherical dome might be the half cylinder laid on its side.

This is what I am building to save money over a GRP dome.

The cylinder is an easy shape to cover with flat sheets of plywood or aluminium.

Domes are certainly not.

 

barrel cylinder dome txt rsz 500.jpg

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Wot - got no skills?  Hemispherical DIY domes every time for wind, LP and dew protection for scopes and user !  And it can be done with cylindrical sheet panels :)

Nytecam 

eaa scope gdn2.jpg

Edited by nytecam
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2 hours ago, nytecam said:

Wot - got no skills?  Hemispherical DIY domes every time for wind, LP and dew protection for scopes and user !  And it can be done with cylindrical sheet panels :)

Nytecam 

The hemispherical dome has much the same radius overall.

The half-cylinder provides greater space at the shoulders where longer instruments are involved.

If it's good enough for Peter Drew, on a windswept moor, then it's good enough for two of them.  :happy11:

Borrowed from the Astronomy Center UK website:

 

 

 

 

astronomy center barrel domes 3 rsz 500.jpg

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When I planned my observatory, I decided that security was the deciding factor.

Do I want a dome that is obviously containing astronomy equipment ?

Or a ROR that looks like a shed ?

 

Nigel

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Just now, nigelg said:

When I planned my observatory, I decided that security was the deciding factor.

Do I want a dome that is obviously containing astronomy equipment ?

Or a ROR that looks like a shed ?

 

Nigel

Ah, but a shed can contain easily fenced, power tools and other stuff.

A dome usually contains something you can't easily carry away, nor easily sell on.

Only a knowledgeable thief would steal a telescope.

Can you imagine the word going round the pub?

"Pssst! Anyone want a 36" f/8 truss Newt?

"Tell you what.. I'll throw in the split ring, English mounting if you like."

"Going cheap! No rust. It's in the van, if you're interested?"

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1 hour ago, Rusted said:

A dome usually contains something you can't easily carry away, nor easily sell on.

Only a knowledgeable thief would steal a telescope.

I am far from convinced a thief would go through a thought process like that.

The first thing that would happen would be a few hundred £££s of damage as they smashed their way in. After that it would be "Oh, no tools - never mind, there's a few bob of scrap metal - I'll have that" and your £x-thousand pound pride and joy gets the thief maybe £10 at the scrap yard. Once they've sheared the OTA off and tossed it on the floor.

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Pete,

I feel your pain.

I had my rural workshop broken into and all my power tools and other items stolen. :hmh:

Fortunately I had no observatory to act as a control for your theory.

However, I can report that the thieves seemed uninterested in the concrete-filled pipe sticking out of the lawn. :thumbsup:

 

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Clearly a largely closed structure like a dome is best in the wind. However, you can also have a simple rectilinear rotator. Eiither the whole thing can rotate or just the upper part. In a nutshell you can have a cuboid 'dome' which will give the same level of protection against the wind and be easier to make. It might also provide more headroom. Interestingly the professionals seem to have gone off domes, I gather because of a phenomenon called 'dome seeing.' It may only apply to large domes and very long FL instruments, I don't know.

http://www.eso.org/gen-fac/pubs/astclim/papers/lz-thesis/node53.html

The MMT has a square total rotator.

http://www.mmto.org/node/2

This might, in amateur guise, have the advantage of keeping the observer and/or PC at the opposite side to the aperture.

Olly

PS I find that high wind, at least in my neck of the woods, plays such havoc with the seeing that I'm not much tempted to proceed.

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Something similar to the "flattened dome" shown above, I build a 3 x 3 mtr breeze block walled (1.5mtr high) observatory topped with an octodome "dome" - used 4 x 8' ply sheets to give 4 x 4' sides with one face providing a opening, with double doors of 4 x 4' and a sliding opening section on the top. Plenty of head room. Easy to build - all flat surfaces.

 

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On 31/03/2017 at 00:28, Merlin66 said:

Something similar to the "flattened dome" shown above, I build a 3 x 3 mtr breeze block walled (1.5mtr high) observatory topped with an octodome "dome" - used 4 x 8' ply sheets to give 4 x 4' sides with one face providing a opening, with double doors of 4 x 4' and a sliding opening section on the top. Plenty of head room. Easy to build - all flat surfaces.

Do you have picture of this at all please?

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On 30/03/2017 at 18:43, ollypenrice said:

 Interestingly the professionals seem to have gone off domes, I gather because of a phenomenon called 'dome seeing.'

Olly

PS I find that high wind, at least in my neck of the woods, plays such havoc with the seeing that I'm not much tempted to proceed.

 

I wonder whether a fully perforated wooden floor wouldn't solve "dome seeing" problems in amateur sizes.

Evenly spaced planks might suffice to provide a large [entirely passive] throughput of rising air, via the chimney effect, up and out through the slit. 

It would save drilling thousands of holes in a chipboard floor. It would also need an open door or stilts to provide the free flow of underfloor air.

Not much help for concrete floors though and it might be a bit chilly on the feet. Since the underfloor air should be at ambient.

 

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Looking well used....

My mate found some (reject) double glazed windows from the hi-speed train - I fitted a couple into the Octodome....

You can see the double door on one side of the Octodome. the sliding roof section ran on upside down sliding door rollers.

The 12" f5 Canopus was used for SN Search.

Hope this helps.

Observatory 1984.jpg

canopus320_1984.jpg

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On 30/03/2017 at 12:54, michaelmorris said:

Some people have created flattened-dome observatories that look a bit like a shed.

gallery_13389_111_1338790306_1004.jpg

 

That looks like a WWI machine gun emplacement.

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