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Beach House Rooftop Observatory

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16 replies to this topic

#1 giganova

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Posted 21 August 2021 - 01:27 PM

Hi all --

 

I bought a lot at a beach in Delaware, designed a house with an architect, and site work will start in a few weeks. The house will have a 14x14 feet roof-top deck I want to put my telescope on. I will mostly do astrophotography and occasional visual observations when we have guests. Skies are pretty dark at this remote beach, Bortle 4, no streetlights, no town within a 10 miles radius.

 

The architect's renderings have a tiled floor, sofas, a fire put, etc, but in reality it'll just be an empty wooden deck.

 

What do you think I could put up there? I was thinking about permanently installing a steel or aluminum pier and securing it to the deck, and have a quality mount permanently on the pier, protected by some wooden enclosure? Maybe put another deck sitting on rubber pads on top of the deck to minimize vibrations. At night it'll just be me on the deck, so not many vibrations. 

 

Curious to hear what you think, thanks!

 

51393869320_ea252f04e2_c.jpgBACK (2)

 

51393114773_511634dc7b_c.jpgBACK (1)

 

 


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#2 petert913

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Posted 21 August 2021 - 01:34 PM

Beautiful home design.  I would be a bit concerned about vibration if the scope and pier are just attached to a wood deck.  Should think of a way to isolate vibration.  Congrats, though !


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#3 17thCentury

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Posted 21 August 2021 - 02:13 PM

Don't know that I'd put a secondary wooden deck on top of an existing wooden deck. Sun and air currents are probably beneficial to keeping fungi and moisture from creating havoc to the roof.

Also not sure a padded supported floor offers any real vibration dampening. I would think if you get the weight and contacts points wrong you might be creating a trampoline effect.

 

Very nice home. I'd really think hard before adding permanent piers and drilling holes in something.

 

 

Though would definitely be nice to have a pretty cabinet somewhere to display astronomy toys.


Edited by 17thCentury, 21 August 2021 - 02:17 PM.


#4 Maritime

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Posted 21 August 2021 - 02:40 PM

I live in the city of Seattle, blocks from Lake Washington. The street in front of my home, which faces West, is a thoroughfare, with 24 hour bus traffic.  My home has three stories, and is built on the side of a ravine: two stories are above grade and there is a roof deck on the top, with elastomeric coating over plywood. I use the deck for visual astronomy and astrophotography. My largest scope is an 8 inch Celestron edgehd, and I use an avx, an heq5 pro and an evolution mount. Walking on the deck produces slight vibration, as do the buses. However, using subs up to three minutes, photographs seem unaffected.

 

my home is cantilevered, with some kind of internal bracing. 
 

my experience suggests a permanent base or pier would only be affected by walking at your site, and then only mildly. 
 

we carry our gear up each use, and when standing at the scope find the setup quite stable for visual. For photography, I use an ASIAIR pro, and start sequences on the lower floor. 


Edited by Maritime, 21 August 2021 - 02:41 PM.


#5 Marcelofig

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Posted 21 August 2021 - 03:18 PM

Beautiful house. If it is still in the design stage I would ask the architect to design the deck with a central area isolated from the rest of the deck to put the pier there and avoid vibrations. Very similar to the design presented where you can see a pebble gravel to put the fire pit.

 

Also once all the equipment is mounted I would control everything remotely from inside the house.


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#6 GaryShaw

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Posted 21 August 2021 - 05:56 PM

Hi

If you are truly planning on doing serious AP from that location, you will need a pier (steel could work) running from that roof/deck level down to a concrete footing/foundation at grade. The pier will need to be isolated from the rest of the structure - especially the walking deck at the telescope location. Some attention to waterproofing will also be required at the separation 'gap' between the pier and the building structure. Having a separate walking deck alone will do nothing to eliminate vibration since both 'decks' will still be supported on the roof rafter system supporting that deck area. Without an effective vibration separation, vibrations from foot-fall, doors closing and the normal movements in a home, will vibrate the scope and impact the images.

 

If you are doing EAA, however, the vibrations will probably be more tolerable as long as the walking surface adjacent to the scope is separated from the surface supporting the tripod/pier (portable in this case). The screen images will definitely jiggle a bit but EAA 'observation' would tolerate that fairly well while any captured images would suffer.

 

If AP is truly the goal and that roof is the only location option, discuss some room layout redesign options with your architect to permit the pier to rise from grade to the scope location. A good designer could easily work that out and redesign fees will be trivial compared to the cost of fixing the vibration problem later, once the structure is in place.

Good Luck.

Gary



#7 giganova

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Posted 21 August 2021 - 06:01 PM

Great tips, thank you!

 

I think all I can do is isolate the pier from the walking deck because having a separate pier that goes all the way to ground is not an option due to the room layouts of the house (and cost prohibitive). I am not too worried about vibrations because at night when I will be doing astrophotography, I'll be the only one awake in the house.



#8 Am33r

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Posted 22 August 2021 - 07:22 PM

A few things.

 

One way or another, isolate the base aluminum pier from the walking deck. This can be done by mounting the pier stand to the ceiling platform rather than the deck above it. Fill the resulting gap with silicone.


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#9 Umasscrew39

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Posted 24 August 2021 - 03:53 PM

You can do what I did.  Run a cement pier from below the foundation up to the rooftop, and then place a steel pier on top of that and then your mount and scope.  I do AP and it is rock solid on my observatory floor.  So, it will work the same on your deck.  Only other trick is to have a small gap between the cement pier and your decking.  Other than that, you can jump up and down on the deck and your imaging will be stable.

 

Here are a few pics when we started building it to give you an idea.  The cement pier is about 4ft below ground level.  I put a ROR on top of the second floor which we built over the garage to make an observatory but the cement pier and steel pier would be the same for your interests.

 

BTW- I am from Philly but never saw B4 skies when in Delaware- good for you!

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#10 GaryShaw

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Posted 24 August 2021 - 05:42 PM

Of course you decide what vibrations you can deal with but just be aware that separating the walking deck from what your pier rests on is an inadequate solution since both the pier and walking deck are supported from the roof framing. Your footfalls on the ‘separated’ walking deck will cause vibrations to the pier and optics. If you truly plan on doing serious AP, you will need to set things up for totally remote management of your imaging process. Don’t be walking around the roof deck at any time while you are imaging. Also, be mindful of wind-generated vibration up there as well. 
Good luck

Gary


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#11 John Fitzgerald

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Posted 24 August 2021 - 06:05 PM

Up to you, of course, but if you cannot put the scope on a solid, isolated pier, the results will probably be unsatisfactory, and, ultimately, a waste.



#12 Tangent

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Posted 24 August 2021 - 06:19 PM

This is probably outside of your architectural preferences, but you could put a freestanding observation platform just behind the existing firepit deck;  this way the pier would not interefere with the existing house structure.  If it was me I would put an actual dome over it and turn it into an observatory.  



#13 John Fitzgerald

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Posted 24 August 2021 - 07:03 PM

Beaches in Delaware are subject to hurricanes.  I would put an elevated, free standing dome on the side of the yard away from the beach, somewhat protected by the home. On the roof, it would be more vulnerable.



#14 Umasscrew39

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Posted 24 August 2021 - 07:13 PM

Actually, if he builds an observatory on the top like I did with the proper structure he can image successfully and not have to do it remotely. In central Florida we don’t usually get the brunt of hurricanes but we get very strong winds and thunderstorms. So, I had hurricane straps installed all around my observatory roof. If built correctly, he can image up top.

#15 giganova

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Posted 24 August 2021 - 11:05 PM

Thanks for all your input, very informative! I hear you say the following:

  1. Not working: Pier on deck, too many vibrations (even if I sit next to it on a chair and try not to breath for hours).

  2. Might Work: Concrete-filled steel pier (mass is your friend) secured to the frame of the top floor, isolated from walking deck as much as possible, air conditioning/heating on separate piers next to the house, don’t walk (much).

  3. Should Work: Above + remote observing (which I could do because the room below the roof-top deck is my office which could serve as control room).

  4. Best: Have separate concrete pier next to the house, completely isolated from the house, extend the deck on the 2nd floor and isolate it from the concrete pier. Best to have a dome to protect equipment from storms. Don't build too high because of winds. See illustration.

I think I’ll try option 2) first, then option 3). If that doesn’t work I’ll try to talk my wife into build a separate pier (option 4).

 

51400156582_a23345a93d_c.jpgRooftop Observatory


Edited by giganova, 24 August 2021 - 11:21 PM.


#16 giganova

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Posted 24 August 2021 - 11:37 PM

BTW- I am from Philly but never saw B4 skies when in Delaware- good for you!

It's a remote beach with very few homes, no street lights, and the nearest (small) town is 10 miles away.

 

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Edited by giganova, 24 August 2021 - 11:43 PM.


#17 MJB87

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Posted 25 August 2021 - 06:38 AM

You've gotten some good advice regarding the issue of structural vibration. Just want to point out that thermal issues may also play into this. You might want to think about roof materials, wall materials, etc. that limit the amount of local air turbulence caused by heat dissipation in the evenings.




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