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Old 13-07-2018, 06:08 PM
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lazjen (Chris)
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Elevated Sirius Observatory

I'm moving from the city to a "rural residential" area in the Sunshine Coast hinterlands (mountains). It should be a lot darker, although not perfect - compromise for work, etc.

Anyway, I've got a 3.5m Sirius Observatory Dome that I will be moving from my backyard to the new home. I'm in the process of scouting a suitable site on the new property. The greatest challenge is the slope - it's on the side of a hill.

My original thought was to level the area I want the dome, put in a slab like I have now and whack the dome back on top. And I may still do this, but I'm concerned about water flow from uphill and drainage, etc.

So now I'm considering a raised platform, with the pier isolated from the floor (and separate pillar into the ground). Which of course leads to a few interesting questions: what should I make the pier from? How big do I need to make it - especially if it comes up out of the ground? Concrete? or Concrete + Metal pole?

I'll also have to be extra careful to stop crawlies coming up through the floor and/or the gap to the pier isolation, etc.

Anyone done anything like this? Any pointers (I'm going to do some more googling later )? Am I insane to consider this?
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Old 13-07-2018, 06:48 PM
Graeme Bluestar (Graeme)
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Chris,
Both my domes are on elevated platforms - can have a yarn with you about them at the next meeting if you like.
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Old 13-07-2018, 07:09 PM
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lazjen (Chris)
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Graeme, that would be great. I'm not 100% certain I am going to make it to the next meeting as yet, but if I get there I'll catch up with you.

Any chance you could email me some pictures?
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Old 13-07-2018, 07:31 PM
thebonz (John)
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elevated observatory

Hi Chris
I put my 2.3 meter dome on an octagonal merbu timber deck raised about 40 cm off the ground. It works a treat. The biggest thing for me was ensuring that the platform was level as this effects the rotational performance of the dome.. I was able to screw the base of the dome into the joists ensuring stability.
John
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Old 13-07-2018, 07:39 PM
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lazjen (Chris)
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John, sounds good (any pics? ).

Do you have your pier isolated from the deck?
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Old 13-07-2018, 07:46 PM
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theodog (Jeff)
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Quote:
Originally Posted by lazjen View Post
Am I insane to consider this?
No, Here's mine, still going strong nearly 2 years later.

http://www.iceinspace.com.au/forum/s...ht=observatory

Go for it.
I clamped blocks, with felt on the bottom, around my piers but just touching the floor to cover the isolation gaps. The felt stops most creepy-crawlies.
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Old 13-07-2018, 08:19 PM
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lazjen (Chris)
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Jeff, thanks. Nice setup. The steel frame is a good idea although I suspect that's going to add to the cost a bit I guess. I have been leaning towards a timber deck although termites are a worry. I think suitable termite barrier/gaps should work fine though, after all timber decks are the rage in the area.
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Old 14-07-2018, 02:08 AM
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strongmanmike (Michael)
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Hi Chris I also moved my dome and went from a slab to a 600mm elevated deck which has been much better as far as less moistier and less spiders and improved local seeing. Here is the construction sequence for my elevated 2.3m Sirius Observatory, may give you some ideas?

http://www.pbase.com/strongmanmike20...ux_observatory

Mike
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Old 14-07-2018, 06:13 PM
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lazjen (Chris)
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Excellent documentation. I must remember to do that as well. And it has given me ideas too. I think, for example, I'll go with a ramp instead of stairs. Given I'll be on a slope (not these nice flat areas I've been seeing so far), I can put the ramp on the uphill side and make it a very gentle incline to the observatory.

For those that have responded, is there anything that you would have done different if you could redo?
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Old 14-07-2018, 08:10 PM
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strongmanmike (Michael)
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Quote:
Originally Posted by lazjen View Post

For those that have responded, is there anything that you would have done different if you could redo?
Not really ....apart from perhaps combining the shed with the dome but that would have cost me more and I was on a strict budget the construction went very smoothly, I was particularly happy with the single pour pier and footing, recommend that
Mike
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  #11  
Old 14-07-2018, 09:22 PM
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lazjen (Chris)
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I'm lucky enough that the house will be nearby so I don't need a shed - although grand ideas of expansion plans might see one later on.

I think I might have to go a bit deeper for the footing as the soil seems very soft (I've been told you can grow just about anything there). I suppose I'll have to start digging and see what's underneath.

I'm going to have to consider the footing/pier carefully, as I expect the platform to be higher than yours...
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Old 14-07-2018, 09:31 PM
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So many different ways of doing things, good luck with it all Chris, it will be lots of fun for sure and look forward to seeing what you come up with

Mike
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Old 15-07-2018, 10:15 AM
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Yeah, I wish I could skip over this bit and have a functioning system.

At least I don't have to go this high: https://www.cloudynights.com/topic/5...he-gulf-coast/ !!
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Old 17-07-2018, 06:42 PM
Auster1b (Neil)
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2 storey Sirius

Lazjen,
Sorry should have replied earlier.

This is what I did; currently housing a 14" LX200GPS, needed space for batteries etc.:

Its is a 3.5m Sirius on a 12 sided miniorb clad hardwood frame, stairs were fun.

Reinforced 1m cube footing and 2.3m 400mm dia. column isolated from concrete slab, topped by a 860mm tapered fabricated steel pier.

Neil.
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Old 17-07-2018, 09:54 PM
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lazjen (Chris)
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Almost looks like a wheat silo now! It's an interesting setup.

I know one thing I will be avoiding and that's stairs. Ramp only and as gentle a slope as I can manage it.

I am envious of how clear the area is around these domes in this thread. I still will have heaps of neighbours around me and trees.
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Old 17-07-2018, 10:18 PM
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Quote:
Originally Posted by Auster1b View Post
Lazjen,
Sorry should have replied earlier.

This is what I did; currently housing a 14" LX200GPS, needed space for batteries etc.:

Its is a 3.5m Sirius on a 12 sided miniorb clad hardwood frame, stairs were fun.

Reinforced 1m cube footing and 2.3m 400mm dia. column isolated from concrete slab, topped by a 860mm tapered fabricated steel pier.

Neil.
Love this Neil where is it? Gee I hope you have a railing around the landing outside the dome door now?? Heck, I've fallen off mine once but luckily it's only a 0.6m fall....

Mike
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Old 02-09-2018, 02:13 PM
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lazjen (Chris)
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The dome has been dismantled today and taken away to be refurbished (and upgraded) before it goes to the new location.

I am in the last stages of sorting out the design of the new setup with the builders. I'm going for something like Neil's setup, adjusted for the slope I'm on (also no enclosed panels for the lower half). On the top side, I'll have a ramp to a small landing outside the dome that will have a small air gap to the dome's decking to avoid water seepage issues. The landing will be enough to open the door and to have an easy level place to step onto when coming in/out of the dome in the dark.

Questions:

1. My current plan for the central pier is to have the concrete come up to about 250mm above the deck floor height (and then put a metal pier on top of that). I'm planning to have one of the electrical/data conduits come up with this pier, so I'll have some space on the side of the concrete to place power and data outlet for mount and other gear (there will be separate conduits on the deck itself to supply power and data to other items). Exact dimensions haven't been determined yet, but it's currently projected to be 500 mm in diameter, 2m high with a depth of 900mm (the builder has suggested 600m depth for the rest of the deck for comparison). Any problems with this?

2. For the 3 bolts I'll embed in the top of the concrete pier. What size should they be? I've been considering 18 to 20mm threaded rods, about 1m in length? How much should I leave protruding from the cement for securing a metal pier (which I have yet to obtain)? And for the placement - what's the ideal location, i.e. the distance in from the outer edge, given the 500mm diameter mentioned above?
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Old 03-09-2018, 09:26 PM
Auster1b (Neil)
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Chris, I sort of over did it.
I designed the column and base to the AS, good enough for anything.
It is solid, hit it and it hurts.

Pics of pier base and column reo, base reo and formtube.

I used 16mm gal allthread and locknuts for pier attachment, welded to the reo with enough protruding for a nut and washer, plate, another nut and washer plus 10mm pr so for access/adjustment. The base is only 1m cubed, so only 2400kg-ish. I did not want it to move at that height.
Because I over do it, even at your height I would still want some sort of base depending on your soil type, it does not take much to dig a bigger hole, its only more concrete. Oh, and more reo, don't forget the reo.


Pier was fabricated; I wanted a tapered pier to mitigate resonance and to give more clearance at the top.
Pics show base ring now separated from reo and the pier halves. These were laser cut from 8mm corten, press braked to shape using the cut notches for bend alignment. I welded the Halves together, then welded the end plates/rings (12 or 14mm from memory).

Pier is solid, wedge is wobbly.

Mike, thanks. It is near Swanpool, south of Benalla. Still working on permanent balustrades.

Neil
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  #19  
Old 03-09-2018, 11:39 PM
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lazjen (Chris)
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Thanks Neil.

I'm asking for a more solid footing, because as you say, you can just make the hole bigger and the extra cost is worth it for greater piece of mind.
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Old 11-10-2018, 01:16 PM
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Quote:
Originally Posted by lazjen View Post
The dome has been dismantled today and taken away to be refurbished (and upgraded) before it goes to the new location.

I am in the last stages of sorting out the design of the new setup with the builders. I'm going for something like Neil's setup, adjusted for the slope I'm on (also no enclosed panels for the lower half). On the top side, I'll have a ramp to a small landing outside the dome that will have a small air gap to the dome's decking to avoid water seepage issues. The landing will be enough to open the door and to have an easy level place to step onto when coming in/out of the dome in the dark.

Questions:

1. My current plan for the central pier is to have the concrete come up to about 250mm above the deck floor height (and then put a metal pier on top of that). I'm planning to have one of the electrical/data conduits come up with this pier, so I'll have some space on the side of the concrete to place power and data outlet for mount and other gear (there will be separate conduits on the deck itself to supply power and data to other items). Exact dimensions haven't been determined yet, but it's currently projected to be 500 mm in diameter, 2m high with a depth of 900mm (the builder has suggested 600m depth for the rest of the deck for comparison). Any problems with this?

2. For the 3 bolts I'll embed in the top of the concrete pier. What size should they be? I've been considering 18 to 20mm threaded rods, about 1m in length? How much should I leave protruding from the cement for securing a metal pier (which I have yet to obtain)? And for the placement - what's the ideal location, i.e. the distance in from the outer edge, given the 500mm diameter mentioned above?
Hi Chris, just seen your queries and probably a bit late for a reply, but here's what I did:

Like Neil said, bigger can be better (very impressive work, Neil), so I dug a 2 cubic metre hole for the reinforced concrete pier base; the pier is 450 dia x ~2.2 metres in height. I designed the pier to come up to about 150 mm below observing floor level, and made the bolted connections to the steel pier there. From memory, the 8 bolts (actually probably threaded rod) that I set into the top of the pier were into the concrete by only about 300 mm and had very large flat washers on their bottom ends. I think that they were half-inch size, and gal.

Here's a link to my construction thread: http://www.iceinspace.com.au/forum/s...ad.php?t=36222

and also a link to a more detailed construction article that I wrote for NACAA: http://www.nacaa.org.au/node/393

Looking forward to seeing your progress.

Cheers, Chris
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