My future geodesic dome

[bojan]

The time has come to start preparation for building the dome for my Newtonian, on EQ6.

I decided to go for geodesic, 3v..
The construction will be done in phases:
- building the basic frame elements (hexagons and pentagons with spokes), made of 19x42mm pine beams.
- building the round track, concrete slab for pier, deck (planned for end of this year)
- assembling the dome frame from pentagon and hexagon elements
- cladding the structure with triangles cut from Styrofoam sheet 50mm
- rendering the outer surface with metal mesh and polyurethane.

The dome itself will be a bit more than a hemisphere, similar in looks to this one (http://www.astrodomes.com/), but 3 metres in diameter.

I was thinking about using just styrofoam (rendered with metal mesh and polyurethane) but decided to go with wooden frame to increase the structural strength - I don't want the whole thing to be blown away by high wind, since the dome will be placed on elevated ground, with not many other buildings around.
Also, the wooden frame allows for build-in storage boxes and working surfaces for equipment.

Wish me luck with this project :P

[sheeny]

Good luck, mate. Make sure you keep us posted. It looks like it should be an excellent project.

Al.

[ZeroID]

Yep, good luck with this Bojan. We'll be watching.

[DavidU]

Fantastic, I would love to see it one day. I remember meeting you and your wife at Johns hill.

[Tandum]

bojan, I'm not sure what sort of finish polyurethane gives you but it might be worth while looking at a arcrylic render finish. Taulbmans armawall roll on render (http://professional.taubmans.com.au/public/professional/texture/texture-gallery/roll-on-render.aspx) can be applied directly to styrofoam, no mesh, and gives a hard finish. It comes pre mixed in 15L containers and before application looks like really thick paint with .5-1mm stones through it. I applied it to mine with a trowel and once set, I gave it an acrylic texture top coat. Mine was hit by cricket ball a while back, leaving a small impact crater which I just slapped some top coat texture over to seal it. It's pretty tough stuff.

[ChrisM]

Bojan, that is going to be one very solid dome! Your choice of materials should provide a good measure of thermal insulation too. My 3V dome from plywood (without any frame) is very rigid - even after the aperture opening was cut. Some pics here http://www.iceinspace.com.au/forum/showthread.php?t=36222&page=2 (see posts ~#44)

Have you worked out the width of your aperture yet? Don't underestimate how far off-centre a GEM will put the scope! I'm almost on the limit for mine (at nearly 700 mm), but a narrower opening = more shelter for the scope and operator.

Looking forward to more progress reports.

Chris

[bojan]

Guys, thank you for kind comments.
I will certainly post updates on project progress, as it advances..


Robin, thanks for comment - I will certainly have a look at that.
So, you didn't try to use any kind of mesh?
I was thinking, metal woven mesh may give me the additional strength in case of hail impact...



Chris, your work inspired me to take that challenge.. apart from a need to cut cost (pre-fabricated domes are terribly expensive).
The thermal insulation was something I thought of when I was browsing your thread couple of years ago.. when I was considering whether to buy or to build.
But those days I was working full time, and now I am in "forced" retirement (made redundant last year, and the job market for old, one-foot-in-the-grave RF engineer is very limited recently) - so cost became a major issue - and as at the moment I have enough free time to build myself, I decided to take that approach.

My opening will be 60cm wide - it should be enough for both for me and my 10" Newt, even at zenith (the eq centre-to-centre displacement is 34cm).
It will be a bit of the problem for synchronisation of dome and EQ and meridian flip, but this is something to be dealt with in the future.

For now, I am running a production of hexagons (using the template).. 13 + 2 1/2 are needed.

[Tandum]

Not once I found this taulbmans stuff. A lot of people where telling me to fiberglass it but I'd done a little of that before and never wanted to deal with it again. I was planning to mesh it and use mix youself bags of acrylic render from bunnings. The mesh simply gives the render something to cling to, I wouldn't have thought it would impart strength. You'll be surprised at just how solid a dome is once built. You might want to check with a paint shop to see if the taulbmans stuff sticks to wood but here it was sticking to everything like you know what to the proverbial blanket and if it's under coated in the first place it should be fine. I think dulux make a similar product.

I had to buy the render, it was $130 for 15L and I used one drum, but I did get the top texture coat off ebay really cheap. I had already sealed the dome with external acrylic from another job and had coated it with a texture paint I found on the bunnings throw out pallet which gave it a sandpaper like texture. If you look in the shutter section (http://starshed.net/obs/index.htm) of the obs build on my site you'll see the many colours of the dome before it turned white with the render :)

Here's a pic of where the dome was struck with a cricket ball. It cracked the render so I just slopped some top coat over it to reseal it.

[el_draco]

I'll be very interested to see you progress on this. I've just laid all the cabling to the location I want to put my observatory and am in the design exploration phase a.t.m.

Very demanding process! Location for me is a significant issue. No possibility of a crane on site to lift a dome so I suspect its going to be build on the spot, probably a 3/4 geodesic very similar to yours....

[bojan]

Robin,
your website is very interesting for me.
I will definitely consider acrylic overcoat, when the time comes for that (later in 2013).

Rom, I have the similar issue with my future site - it cannot be (easily) reached by crane so that is why I am doing frames only for now, as a first phase of the project - preparation for the final assembly.

Since in everybody's experience the styrofoam only (over-coated by acrylic or whatever) is stiff enough once assembled into dome, I will probably omit pentagon frames and insert styrofoam-only pentagons in the remaining places (I still think the additional strength achieved by wooden frame is not an un-necessary overkill)

Of course, styrofoam elements (styrodur actually - it is much stiffer than styropor and will cost me $25 for 2500x600x50mm sheet, 18 sheet all in all) will be inserted over the frame once the frame is fully assembled, on the wheels and so on.
Btw, I found pine beams 19x42mm for 55c per metre.. cheap (~130m required.. not a first class material, but still very low rejection rate, ~5-15%).
I am gluing them together with Selleys liquid nails (classic) with the help of a template and staple gun.

Currently my production rate is 1~2 hexagons/day. It could be faster (limited by one only template and the glue setting time.. all timber spokes are already cut to required size), but I am not in a hurry.

[kinetic]

Looking good Bojan:thumbsup:
I'm glad you are finally underway with your dream.
It's a great feeling.
I hope it doesn't turn out too heavy.
What is the projected weight of the geodesic, all up?

Steve

[bojan]

Hi Steve, yes, the dreams are on their way to here :D
I think it will be close to 110kg (more if I go with wheels on the fundament and steel track as part of the dome)
I plan to use 10 wheels (at the corners of each lowest hexagon).. should be OK...

[Tandum]

With that design I'd suggest you look at a bent pipe on the ground and wheels to suit on the dome.

[bojan]

Robin, thanks for suggestion - that's exactly what was on my mind, so now I know it's not a stupid idea :thumbsup:
I just have to work out the details - what kind of pipe (square or "L" or "U" channel profile), how many sections (I can't have it in one piece - too big for transport), how to assemble it in situ (welding for pipe? screws for bent "L" profile or "U" channel?)..
This will depend on my friend (the one with work shop) and his capabilities (or preferences..)
The part of this formula is also motorisation.. and how to mount the cogged belt or curved rack pinion on a dome - I liked your approach - I used similar interface for encoder on my dobson mount, this is way cheaper than the gear made to fit the existing situation, but quite good enough.

[Merlin66]

Bojan,
Back in South Africa, we had a member who built a rotating observatory and used a 100mm PVC pipe bent into a circle as the base runner. It was semi recessed into the concrete foundation. He then used two rubber wheels @45 degree (I think 6 sets in total) to run on the top of the PVC pipe.
Hope this helps.

[bojan]

Hi Ken, this is also an option, thanks for suggestion..
Do you know how the PVC behaved on high temperatures (sun)? I will have 130kg of dome on it (hmmm, the weight will be distributed along the length of the pipe through the wheels.... and the pipe is supported by the recession into concrete.. food for thought.. maybe pipe should be filled with concrete? cheap and easer than metal but possibly good enough.. I will try to experiment when the time comes.)

EDIT:
Being PVC, I imagine it is easy(er) to slightly adjust the final radius of the curved pipe base runner, by simply tightening some kind of the rope (steel?) inside, before filling it with concrete)... so for every cm in radius, the circumference (the length of the rope) must be changed by 6.14 cm..
Interesting...

[Tandum]

Here's a couple of pics from Joe Garlitz, the guy who put the foam dome plans on line in the first place. He's driving his dome like this and gets accurate positioning. The cog drives the home made belt and the magnet clicks the switch as the spurs pass by. I thought it was pretty clever.

[bojan]

Looks good..

I was also thinking about rack (will have to be curved first.. if possible at all), normally used for sliding doors ( I have it on my gate)..

And.. I have one old, spare motor driver unit ("Nice" brand (http://www.niceforyou.com/en/2-sliding-gates.html)) somewhere in the shed.. and wireless remote controller that goes with it as well.

[scopemankit]

Nice one there Bojan. I built a "sorta" geodisic 5 years ago and have no regrets at all.

[bojan]

Hi Chris, thanks for kind comment..
Do you have some pics of your dome?
I haven't decided yet about the track/wheels design, so any input is still most appreciated :)

[el_draco]

I have a couple of options. Leaning towards this one:

[bojan]

I also like this idea - metal tube/track on the dome, to add weight.
The rough calculation on wind load says that 80km/h wind will produce side force of ~900N on the dome profile...
The dome itself will have ~110kg, so a bit more weight will be actually beneficial for stability and the additional anchoring may prove to be un-necessary ( I will still have it, though).

[el_draco]

I have just "inherited" about 1000kg of 300mm I beams that I am going to use for the base of my observatory... if I can cut them :screwy:

That should give the dome a nice firm base to ride on. I might add, it nearly killed me getting them on the ute. :rolleyes: (So glad I learned about levers and rollers as a kid.)

Doing the calculations at the moment and reckon I can get a 3.5m to 4.0m octagon out of this lot. I guess that will equate to 8 rolling surfaces.

Fogive me for I know not what I do.....:lol:

[bojan]

The first phase is finished - all hexagons (13 +1 spare) are ready, and door frame elements as well.
The next phase [assembly of the frame (hexagons only, the pentagons will be made of styrodur without frame) on steel pipe torus, 2.5m in diameter] will continue in October - November... depending on my employment status (if I don't find the job very soon, I will officially retire by end of this financial year - and the schedule for the observatory will be as planned. If I find one, then the whole thing will be postponed for a year or so (so, should I want or not want to find a job ??)

[Ausrock]

What I can't understand is why (to my limited knowledge), someone hasn't made their revolving track system from a lower flat(ish) "u" shaped channel with the upper dome section track made to fit inside on a "bed" of ball bearings.

An alternative to "commercial" coatings may be a mix of cement and PVA (aka Aquadhere), it may require some experimenting to get the correct mix ratio but it could be worth consideration.

;)

[el_draco]

Err, two round bits instead of one....:question:

[bojan]

Actually, I was considering the similar option of course (not two pieces, because this would be too much, as Rom suggested) - U channel on the base and wheels on the dome side.
I even considered making the "u" channel into concrete wall (by impressing the shape with round plastic pipe) or cutting the channel (with router) into the wooden round-ish frame...
But, I figured out that the bending of the round tube into torus is way easier job (at least for my friend who have the necessary facilities) than bending of the "U" channel and/or other alternatives... so this is why I will have the torus, after all.. compromise must be made somewhere, dictated by the local circumstances..
And it will be on the dome side, because of two reasons:
- I want more weight, distributed towards the lower part of the structure, to increase the stability on high winds
- I want to have the firm and stiff base onto which the wooden frame will be mounted.

And, yes, this way it is only one round bit (torus itself).. and couple of (8 in my case) stomps to carry the wheels...

[bojan]

Report on progress: back to square one.

Yesterday we visited property in Seymour where my geodesic dome was planned for next year to be built..

I was not prepared for the shock that was waiting for me in the backyard.. The huge, monstrous industrial-type unit or barn erected next to our property by our northern neighbour while we were away.
I noticed that he has some (very loud, with earth-moving machinery) work being done over the fence while we were there last time (late January?) and I asked him what it was.. he told me he was securing the terrain next to our fence from sliding (which doesn't sounded like the bad idea), and later he was going to build the shed there.. to which I agreed in principle, but I had no idea it was going to be THAT big and THAT high.
I am wandering now how it was possible that nobody (including agent who manages the property) hadn't contacted us prior to issuing the building permit (If I knew for this plan, I would have strongly objected to this so called "shed" to be placed next to our northern fence, effectively casting the shadow into our backyard during winter time.. not to mention the totally ruined view to the north sky).
So.. what to do now?
It seems I am forced to go up 3 metres or so.... or to forget about the whole thing in Seymour.

[el_draco]

Geez, that's just really nasty, I reckon 45 degree obstruction... goodbye ecliptic... Maybe worth trying to negotiate with a local farmer or someone similar. I look at my site every day and know how lucky I am. I can see clouds without any obscuration at all... :lol:

[ZeroID]

THAT is a bummer ! With the slope you have you aren't going to gain much by moving down the hill either and what about heat currents off the roof ?
That really sucks .... :shrug:

[bojan]

It is a disaster.

If I go up by 2.5m, I could compensate for the hight of the building.. but the whole idea completely lost the meaning... not to mention the need for permit and unexpected expences.

I think I will sell the property and move somewhere else.

I checked the legality of the whole thing with the local council, he did his homework, everything is as per current regulations.. he only forgot about simple and common sense courtesy and peace with his neighbours.

[mswhin63]

Maybe you can look into the closeness to the fence line, i think there needs to be a certain amount available. Still may not make much of a difference.

One other thing, the only requirement for a shed that high is for potential commercial reason, it the area zoned for residential or dual.

Good luck either way

[ZeroID]

In NZ side and rear boundary restrictions are only 1.2m but there are height covenants to protect sunlight etc. But they would only apply to a dwelling, not a section.
I see no easy solution especially as you gave him a verbal 'nod' earlier without knowing what was to follow.
'Fait Accompli' methinks .....time to move on.

[bojan]

Exactly right.
Time move up 3metres.. or elsewhere.

[alistairsam]

that's really unfortunate Bojan.

won't it help moving your dome's location to the other side of your backyard, furthest from the fence? you might get down to about 30 degrees and you usually wouldn't want to image or view below that anyways?

which direction is that?
I have a similar issue with a tall house on my west but doesn't cause much of an issue as I don't image in the west.

its a shame how you're forced to sell your home and move just because of someone else.

Alistair

[bojan]

My problem is created partly because the property is on the hill side, so moving away from that monstrosity (to the south) means moving lower down the slope, which doesn't help at all.
And since the whole view to the northern side of the fence is blocked by the barn, moving to either side doesn't help either.
The Vic building regulations are set in such a way that they do not take into account the full set of interests of the neighbours, including those strange requirements like unobstructed view to the sky, or light pollution etc..(he was not obliged to tell anyone of anything, as I have been informed by the planning authority in the council, which I found to be very strange.. but that means I do not have to tell anyone of my intentions either.. which I certainly would because I definitelly want to have a good relationship with people living nearby).

[ZeroID]

So build an Observatory on stilts .... and don't tell anyone. ;)
The precedent has been set .... :P

Joking of course but I can feel your frustration .. :sadeyes:

I know you're losing the northern aspect, planets etc but how good is your southern view ?
I ask because I have no northern view due to a large volcanic hill. I marginally get a planetary chance at the highest point for a few hours although it is badly compromised by thermal and light problems. I do not have an Eastern at all, CBD, LP and trees to about 80* and my western sky gets to about 35* ona good night.
My southern SCP view and a slice of the sky from Nth 50 to Sth 30 and about 60* wide is it so I just have to be patient and wait till it all comes round next year.
Is this at all an option or viable ?

[FlashDrive]

Bojan ... great idea you have there ...looks very ' futuristic '

Shades of ' Pine Gap ' .. .. they may even ' sign ' you up to track Satellites .:D

Nice work ....

Col.

[PeterHA]

I would seriously consider to lift your dome 1-1.5 m off the ground.
It will need a more substantial concrete pier as it is higher but for the dome and platform a timber construction will do.

[bojan]

Yep..
I am considering going up by 2.5 metres actually.

[ZeroID]

:thumbsup: Excellent, at least you won't have to worry about lights coming over from that side of the fence... bl00dy great light block !!

[bojan]

Well, as our "dream" property in Seymour turned into a nightmare... last month we sold it and closed this particular chapter of our lives.

Now we started to look into Ballarat and surrounding areas to buy a residence.. The town itself is of right size, and has well enough support for a pair of +65yo pensioners (gas, water... doctors, hospitals, graveyards....)

Does anybody have direct experience with the area ( some time ago I had some replies from Leon about Ballarat in general, but maybe the situation changed in the last 6 years)?
Are there any suitable (elevated) suburbs for building backyard observatory?
Are there any areas to avoid (floods, LP etc.)?

[clive milne]

The main problem with Ballarat is that summer often doesn't fall on a weekend.

[bojan]

We spend two weeks in our new property (future home when I retire) in Ballarat.

I did some measurements of the terrain and existing buildings on property... Also talked to neighbours about my future observatory, and so far there is no visible resistance to the idea of placing a dome (slightly elevated on a deck) in one of the corners of the block.
The niche with windows will go, the deck will be built as extension to the existing floor, the existing door will be access to observatory deck.
Fingers crossed...

[bojan]

I hope by the end of this year I will start work on my observatory in Mt Pleasant, Ballarat...
And for that job I will need a steel ring ~ø2.34m, made by bending ~50-70mm steel pipe, (base of the geodesic dome, which will roll on rollers).
Does anybody know of a good bending service in Melbourne or Ballarat (preferred)?

[ZeroID]

Can't help you there but glad to see you're back on track to complete your dome. Got me thinking again for a modification to my setup.

[billdan]

Bojan, you could try exhaust pipe outlets in Ballarat, they usually have pipe bending machines in their workshops.

[Boozlefoot]

Hi Bojan,
I used to work in a bearing centre and we had a customer who made massive solar panel tracking units for Telstra. He simply affixed light British Standard chain to the lower ring of the unit and drove the unit as per Garlitz's drive. The chain comes cheapest in a 10ft box with a joiner link. No bending, curves naturally, inexpensive, off the shelf. Tack welded every 3rd/4th link. "BS 06B-1" is heaps strong enough for the job, and a simple plate sprocket also readily available. (We went through the rack option first then came up with this method)

[QUOTE=bojan;968234]Looks good..

I was also thinking about rack (will have to be curved first.. if possible at all), normally used for sliding doors ( I have it on my gate)..

And.. I have one old, spare motor driver unit.

[bojan]

Excellent idea, thank you!

[Tandum]

A google for Ballarat pipe benders gives -> http://www.plinius.com.au/

[bojan]

Hi Robin, thank you.... I know about them, they are near our place... found them last year in local papers. Actually I went there sat before last and talked to a young lad (he dropped in the office to get something) and I left my phone number, but noone contacted me since ... it seems they are not interested or just careless because they never responded to 2 or 3 of my messages left on website last year.
True, I never tried phone but still....
Last year I have an offer from bend.com.au (they are in Melbourne, Clayton area). Most likely I will go with them if they confirm the quote, transport to Ballarat will be a bit of a problem, but not a show-stopper.

[ChrisM]

Hi Bojan,

I had a 12 m length of 75 x 75 x 6 mm angle iron bent by Uneek Bending in Dandenong South. The resulting ring (3.6 m dia) was too large to trailer home in one piece, so was cut in half for transport then welded on site. From memory, supply and bending cost me <$300 albeit nearly 10 years ago. Uneek Bending are specialist benders used by heavy industry in the Latrobe Valley.

Also check out Rod Stubbings website: https://rodstubbingsobservatory.wordpress.c om/dome/

I can't recall how he bent the pipe (your turntable design sounds identical to Rod's) but I'm sure that he'd be happy to advise you. There is a good picture on the home page. I think his dome is about 3.5 m dia and it turns like a dream.

Good luck, Chris

[bojan]

Chris,
Thank you for the link, I will look at it.

At this point, I intend to go with Smithweld (they are in Tottenham), they quoted $140 for bending of two halves, I need to supply the pipe (65NB).
So far so good...

[bojan]

I am looking into decking...

And I think I found an interesting alternative to conventional approach with treated pine, the deck material is made of recycled plastic.

http://www.enduradeck.com.au/?gclid=CJCWnqvi_dQCFUpWvQodSUMEng
http://www.replas.com.au/

Using the galvanised piers, 10m2 could cost a bit above 1k$.

Anyone has some experience with this?

[Visionary]

Bojan,

We have used recycled plastic/wood decking. It's a wonderful material, entirely without grain, or faults of any kind. Cutting and forming the material is a decided pleasure, the only limitation is your own imagination as there is no chipping, splitting or warping. The more obvious characteristic of "timelessness" ie: the fact no surface treatment is required to preserve the product is a huge benefit.
Our deck is built on pillars as our backyard falls away sharply, the deck is absolutely rock solid! The plastic/wood is heavy and dense and transmits vibration poorly, I believe it would be a brilliant candidate for an Ob.
At Bunnings and other retailers of the product you can source reasonably sized samples of the product, however, I would recommend you to buy a couple of meters of assorted product and simply have a play around with the product. You will quickly discover the materials virtues and establish the products bonafide's as an anti-vibration material.
The clearest evidence of the utility of the product is that I have kept every offcut and use the offcuts for every conceivable problem.

[bojan]

Getting there...
Base ring for dome (2.533m in outer diameter, 2 sections) was picked up from Smithweld today.

The next step is to transport it to my future observatory in Mount Pleasant, Ballarat

[xelasnave]

Excellent.
I am happy you are doing the important things.
Time is now more valuable than money.
Alex

[bojan]

Yep.. probably not much of it is left so... I'd better hurry a bit with this (and some other important projects).

[xelasnave]

When you stop you wonder why you did not stop earlier.
Good luck.
The key is having projects..the observatory is perfect...
Don't worry about money there is never enough and one day you find there is more than you can spend.
Alex

[bojan]

So much for "guarantied" tolerances of +/- 3mm...
This gap is ~22mm wide.
There will be some persuasion needed to join those two ends.

[bojan]

Inspection of hexagons over weekend (they were stored for couple of years at friend's place, they are now in Ballarat, in the room next to future observatory).

The glue I used for joining struts ("liquid nails") is rubbish.. couple of struts felled off, so yesterday I applied screws to hold them back together on all 14 hexagons.

At the end this will not be a serious problem, as my intention was always to final assemble the whole structure together by means of screws and perforated steel tape (still searching for 20mm wide, 0.5~0.75mm variety... ).

And still waiting for ring to be welded together...

[Boozlefoot]

perforated steel tape (still searching for 20mm wide, 0.5~0.75mm variety... )

Hi Bojan

I'm building a truncated trapezium, using ply panels and perforated strap joints/screwed, as well as epoxy infill. I intend to use Pryda Speed Brace which is 25mm x 0.8mm in either 6 or 15 metre rolls. (SB082/6, Also known as hoop iron in this size). Pryda has a good catalogue available online.

Regards, Rod

[bojan]

Hi Rod, ,
Thank you for the tip.
I know about Pryda, 25mm is a bit too wide (my struts are 20x40mm), but then again it is possible to cut a wider tape into two narrow ones..

Some time ago I found this in Bunnings, but I think one strip was 88c ($13 or so on ebay !!! ).. too expensive since I need quite a number of them (~70 pcs for one side only... )

[bojan]

Last weekend I had a discussion about my future dome with my south-east neighbour... she mentioned building permit (I believed this may not be necessary because the whole object will have footprint a bit smaller than 10m2.. then I went to Ballarat Council website and found out that for any size deck (and the platform on which the dome will be mounted is just that - deck) the building permit is required, not only in Ballarat but all over VIC.
I think I will have to go to council and talk to somebody before I start any serious planning.

As for the location itself (corner of our property, extension to the existing room above the garage/workshop) they were not very enthusiastic because the dome will dominate their north-west view even when the higher fence is in place (see attachment), also their privacy may be potentially violated by my presence in the dome... but there was no open resistance to the idea as yet... They said if in the future they felt their privacy is affected they will plant a tree (I am not sure I really want such outcome, the tree will block my view to the South_East) or I have to rise additional 0.5 metre applied to the full length of the fence (on my expense.. which is also not desirable outcome).
I tried to assure them the whole thing will be remotely controlled from the house, not sure if I was successful.

Per aspera ad astra... almost literary.

[bojan]

Semi-rings are at the location finally.., waiting for assembly into one ring.
They will be assembled (welded) together once the 8 steel pipes (stomps that will support the dome and floor of the obs) are in place and levelled so the ring can rest on flat plane.

I was thinking about the rollers, attached picture illustrates one possible alternative.
Rollers could be made of metal or some hard plastic, shafts will be M10 ~ M12 screws (high tensile). I think there will be no need for ball bearings as the dome rotation is very slow and occasional.

[xelasnave]

Hi Bojan
I know you have been planing to have a dome but I suggest you consider something like I am working on particularly as you say operatuon will be remote.
I can fit my 8 inch on a eq6 in a four foot cube box.
Iy costs little and your neighbours would not see it.
You could have something like I have in mind up and working in a week or two.
You are rather competent why not think how what I suggest could work to your advantage.
I will try and get mine finished when zi get back to Sydney and let you see how everything fits.
Like if you are not standing by the gear all the time you simply dont need the room we tend to think we need.
Alex

[xelasnave]

I doubt if you need coucil approval for a four foot cube box.
Mine will be a little taller but only because I made the pier too tall. But its easier to extend than build another pier.
Alex

[bojan]

Alex,
Thank for suggestions, give us some photos when convenient.

As for council approval, anything called shed, below 3m in height (measured from top to ground level) and 1.5m away from fence is OK.. and my dome is 3m in diameter, so it fits the requirements.

[Boozlefoot]

I was thinking about the rollers, attached picture illustrates one possible alternative.
Rollers could be made of metal /

Bojan,

I have alloy "vee"rollers on my boat trailer. After battling with urethane ones for some time, I swear by them.

They work very well, but are hard to come by, and were app $8.00 each. I think the urethane ones will eventually get a flat spot from static loading as do so many roll off's using urethane castors.

Rod

[bojan]

Summer is still present in Ballarat... still not a good time to start excavation work for pier.
Due to draught, (and type of the soil) ground is deeply cracked, see attachment.
It seems I will have to dig quite deep to ensure the concrete fundament for pier is solid enough not to move on it's own (in my Mt Waverley backyard, 70cm was enough, the pier didn't move a bit for the last 4 years).

BTW.. anyone knows where I can buy the protection for gutters as on attached picture?
This weekend we replaced the gutters on our house, and I would like to prevent clogging with leaves and other objects (we found 8 (!!) tennis balls in the old gutters, contributing to water flow problems)

[xelasnave]

I will come down and I promise it will rain non stop.
Let the hose trickle to soften the ground that way you can dig while its still hot:)

Alex

[bojan]

Alex, you are most welcome by me.. but not sure how about the rest of us here in VIC....

[xelasnave]

Bunnings had a cheap post hole digger...buy one do the job and sell it...or hire one...so much easier.

[xelasnave]

I was born there but they wont let me come back.

Alex

[bojan]

Yep, I know and I have one already... $95 or so
Problem is, soil is rock solid at the moment

[xelasnave]

My fathers family were in Ballerat my grandfather was a Police Sergent there.
I think he invented police brutality.
Alex

[bojan]

My southern neighbour is police officer.. he seems to be OK...
But because of his wife i had to change my plans for observatory.

[xelasnave]

Hi Bojan
Here is the cube I was talking about Alex

[bojan]

Looks like I found a suitable rollers. (https://www.ebay.com.au/itm/3-Cotton-Reel-Boat-Trailer-Bow-Roller-Blue-Polypropylene-Brand-New/171184413193?_trkparms=aid%3D222007 %26algo%3DSIM.MBE%26ao%3D2%26asc%3D 20140106155344%26meid%3Dd2efc523259 5444481f0afcca1f8820e%26pid%3D10000 5%26rk%3D4%26rkt%3D12%26mehot%3Dag% 26sd%3D183352605734%26itm%3D1711844 13193&_trksid=p2047675.c100005.m1851)...

[bojan]

Wheels arrived today...
I will try to machine them with help of my CNC lathe (first job!) - 10 pcs is a bit too much for manual operation.

[The_Guru]

Hi Bojan
Any update on the rollers?
For my observatory I had the dome rollers machined from solid ACETAL plastic rod. It has all the properties that I hope will make them long lasting. So far after many months all seems good.
Cheers
Ian

[bojan]

Hi Ian,

Not many news at the moment - the rollers are here, waiting for everything else.

I also prepared square hollows (86 x 86 x 6mm, 200mm long) that will be slipped onto ø96mm tube, as adapter for the rollers with shafts (high tensile bolts). Will post the drawing later today.

[bojan]

This is what the support pillar (one of 8) for dome ring will look like.

[The_Guru]

I have high tensile bolts for the rollers to run on (and a bit of grease) and have had no problems.

[bojan]

Yep.. I plan to use ø18mm bolts

My dome will be no more than 2500N total.. plus wind load.
So let's say 300N max per roller average, and ~1000N when windy. Those bolts should sustain this without problem.

[bojan]

Now I am facing a dilemma (again) - It occured to me that it may be better to use the existing room (study on top of the garage) for observatory...

The only drawback is, I need a relatively high concrete pier (~3m?) which will be built in the back of the garage/workshop (it won't take much space there so workshop would remain functional), going through the floor of the upper room (study),where there will be an elevated deck ~0.5m around the scope (which needs to protrude though the roof of the study)

The study roof is leaking (so far I couldn't figure where the rain gets in), so it needs repair anyway... with ROR, or with upper segment of the geodome I already prepared for standalone dome in the middle of the backyard.

One advantage would be all the work would be done inside the existing object.. so no need to notify the council.


Anyway.. what will be will be.

[AstroApprentice]

The OrbitJet Observatory might provide you with some inspiration:
https://www.flickr.com/photos/27684115@N07/sets/72157644177074161/
A besser block pier through the house would be relatively easy to construct...

[bojan]

Yes, I saw this...
However, I would still like to use the geo-dome (part of it that is..)... It is stored now in this very study.

[bojan]

I made up my mind - I am going with ROR.


All I have to do is to make the cover (welded steel frame, polycarbonate or colorbond roofing), remove the existing colorbond from 2x2m area in the corner and place two rails (similar to what is used for sliding gates, "L" profile 25x25mm).


The second stage will be to cut the floor of the studio, so concrete pier (16~18 standard concrete blocks from Bunnings, 190x190x390) can be built on existing footing up into studio above.
And that will be it.

[xelasnave]

If you are going to go roll off roof I see no point in the dome other than not wasting the resourses invested to date...however its completion will require more effort than what I expect would be a more sensible option that of a flat roof. It is hard to abandon something but unless you can find a clear benefit of the dome as a slide off over a much simpler flat roof dont fall for the enticement to try and salvage the effort to date on the dome...if you like the dome use it in the manner it was first envisaged.
I do think you need to approach this project more professionally by setting dead lines and a specific completion date.. as at the moment you have no completion date...you must know what that translates to...so can I encourage you to commit to a date when it will be finished...if there was one thing I learned from my race days is that once you have a dead line you will meet it...we completly rebuilt a motor and gear box in three days so it could be raced on day four...these days such a project would sit unattended for years and actually never get done. Why what is the difference..knowlegde and tools are the same but no completion date means only one thing..no completion unless by chance.
Commit and complete and get on with the real aspects of the hobby you enjoy...think of the implications of the term "dead line"☺
Sorry to be preaching I am just trying to help.
Alex

[xelasnave]

I have designed another "cube" style arrangement 8x4x4 with a roll off roof to house both my mounts...I am going up right now to cut the timber☺ although I have not set a completion date which I will do later☺

Alex

[bojan]

Alex, I know everything about deadlines... So I understand what you are talking about.
However, there are many external factors involved in this project (SWMBO is one of them). Another is my retirement... and (non) requirement of building permit (this approach will not need permit as it can be regarded as roof repair - which it is in essence).

I abandoned the idea of dome already - most likely I will try to sell/donate what I already have done, or re-use some items (rollers are already re-allocated to this version).

[xelasnave]

Just retire. Again a date.
There is never a good time to start a business, have a baby or retire...you just have to bite the bullet and do it. Work is a bad habit which you have to break its not easy but it must be done...life is finite and good health is not a given..get in for your share immediately ...time to be slightly selfish...I put off retiring but fortunately I had complete break down and was carried out..I lost most everything lived in a shed but finally it all came good...I wish you all the best of course and just want to see you get to where you want to be.
Alex

[bojan]

Well, I started work on my obs..
hole in garage ceiling /studio floor is where it should be and I started removing the studio ceiling....

[xelasnave]

Good on you Bojan. Please keep the photos coming and try to do a little something each day towards your goal. Good luck I wish you all the best.
Alex

[bojan]

Yep, bit by bit.. I will do as much as I can, to leave as little as possible to tradie (He will do concrete job and maybe a bit on the roof, and I am trying to minimise this part).

[bojan]

For the lid, I was thinking about something like this...
Rail is simple galvanized 50x5 bar (Bunnings), 5m long (it will have to be made from 2~3 pieces).
The frame will be made of 70x35mm treated pine timber, covered with corrugated roofing (polycarbonate? or colorbond.. not sure yet).
It will have to be insulated from below, to avoid/minimise condensation.
I plan to use (Bunnings) garage brushes (https://www.bunnings.com.au/moroday-35mm-x-2-55m-garage-brush-door-seal_p4062457) at edges to minimise wind coming inside.

[Wilso]

There’s light weight insulated roof sheeting that’s available that comes with foam insulation that is self supporting over fairly long spans.
They use it on alfresco areas, I thought would be perfect for a roll off roof!

[mynameiscd]

Hi Bogan ,
This is the sort of thing Darren was talking about.
https://arcpanel.com.au/roof-systems/custom-roof-system/

There's plenty of companies around but its not that cheap. The best thing is its span capabilities.
I built my beach observatory with something similar but never quite finished it (typical builders house!!!).
I used a quick steel frame, screwed the panels on, and then rendered it with acrylic render.
The roof panels just slide apart on rails with no wheels (not finished)
The roof could do with some colourbond but its still waterproof.
These panels cost me about $80 each for 2500x1200x75 with acrylic both sides.
My wife thought it looked a little bare so she got a bit artistic.
My new obs will be similar but bigger and finished
Just a few ideas maybe.
Cheers
Andy

[bojan]

Guys,

Thank you for ideas, i will have a careful look :-)

The thing is, I am a bit limited by existing structure (some possible surprises are still hidden... they will be uncovered soon), but the details are still "plastic"...

[bojan]

I think I have a final solution for sliding roof...
Bunnings slide door guide (https://www.bunnings.com.au/richmond-60mm-hanging-gate-roller-channel_p3962607) (I will need 3 pcs a 2.9m to have 2x4.5m) and wheels (from ebay) (https://www.ebay.com.au/itm/4pcs-2-inch-660lb-Sliding-Gate-Roller-Steel-Wheel-Track-Rail-V-Type-w-Bracket/163214953594?ssPageName=STRK%3AMEBI DX%3AIT&_trksid=p2060353.m2749.l2649), 8 of them, rolling inside on "L" 20mm profile.
The frame will be standard treated pine 70x39 timber, covered with colorbond.

Coming weekend I plan to remove the rest of the ceiling, to expose the roof structure and see how to proceed from there.

[bojan]

The project continues here (http://www.iceinspace.com.au/forum/showthread.php?p=1437452#post143745 2)...