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Thinking of building a pier and observatory but need advice


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Ok so i'm now saving up for an observatory and looking at various items i need to buy.

First off where do you buy small amounts of rebar ??? Been searching for ages and cant find this info.

Also Essex Tubes seem pretty good for the pier surround 8", 5 footer £45, any other places cheaper?

And finally a mount plate for the HEQ5 ? How do i go about getting one, asked Arthur but i think its something he is looking into later.

Hope to get a 8 x 9 Pent shed and modify it to roll off roof, sounds good but i have an 8" NEwt and Orion 80ED, wonder if it'll fit ok. Being at 56 degrees north can result in Orion being a bit lower in the sky and i'm concerned about the wall height. Something else to look into.

Well anyways, clear skies :D

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Is that, that twisted round bar that you often see on the backs of artecs, on their way to sites??

If so, would it not be easier just to buy 12mm/16mm round bar???? 12/16mm round bar should strong enough surely??

Just my 50cents worth, as the North Americans would say.

Cheers, Andy.

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I use gilchrist steel in busby for all my wee bits 'n' pieces. They cut full lengths(or cut plate etc) down to the size you want. I made a metal pier for my Tal 200RS , roughly 4"(?) outside diameter with 5mm thickness. Even if you're not north of the border, i'm sure if you check the yellow pages, you should be able to find someone who'll do this for you.

Don't know if this'll be of help. Hope so tho.

Cheers Andy.

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I doubt you can order rebar over the 'net you'll need to phone someone like buildbase, jewsons or a local company. B&Q/Focus etc dont stock it as it's for "professional" builders (!)

£45 is a blumming bargain for the pipe, jump at it. Are you going to do a concrete fill? If so is 5 foot long enough? You want about 2 foot sunk in the pad if you can. Best bet is a 1 meter cube for your pier base and a 6" float for the pad. Dont forget to keep a gap between the pier base and the pad to stop vibrations. Overbuild but it doesn't cost anything extra.

As for your plate, Arthur is probably best, or look to local engineering firms as delivery is cheaper. These things are heavy!

Roll off idea is the cheapest, compared to a dome. If you are concerned about your wall height you can either go with a taller pier, change to just refractors, or build a drop down wall on the south side. Personally i'de dump the newt and go 'frac or SCT as they tend to be smaller and even an 8x9 is small when it's full of all your kit.

Good luck! Probably one of the best investments in the hobby you can make!

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Well if you carnt get rebar threaded stainless steel rod will do, thats what I used in my original pier which Im about to demolish to make room for my new one:http://www.gdedge.com/astro/DSC00014.JPG

That piers stood for 16 years so I can vouch for stainless steel rod :D

Here's a good link for sheds (cheapest in the UK + free deliveryhttp://www.gardenbuildingsdirect.co.uk/

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OK so here goes with my thoughts.

a) Why reinforce the concrete? The rebar is there on stuctural concrete to counteract the problem that concrete has. It's relatively weak in tension so the rebar holds it together. In compression it's immensely strong and doesn't need help. Bottom line here is you probably don't have any tensile loading on any part of the pier, so rebar is not needed.

:D You might be able to use some 200mm diameter ducting (galvanised steel) available as an offcut (i.e. free) if you contact an air conditioning company in your area. Be aware that after it's been cut it is very sharp and needs the pointy bits filing down for safety.

c) Upgrader's shed link is where I got my shed, I'll second the recommendation there.

d) When you consider the roll-off design, anticipate the blow-off possibilities to avoid disappointment later.

e) Go for it. Having a set up that's polar aligned and just needs to be switched on is so much easier. I used to wait an hour to find Polaris to align, with loads of cloud free sky to the south. Sods law says that the cloud will sit on Polaris all night, so the permanent pier is king.

f) Remember that you can slide the lid on and leave the 'scope tracking the target if you think the clouds are a temporary glitch.

Best of luck with the build!

Captain Chaos

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Well CC has some very valid points, our friends across the pond seem to have competitions about how much steel and concrete they can pour into the ground :p My original pier is approx 500mm high and is approx set in 500mm below ground (from memory), now this pier has not budged a mm in 16 years, total mass is prolly a couple of hundred kgs which carried a 8"Newtonian + mount with no problems.

My new setup is a EQ6 + 10" Skywatcher Newtonian so I'll not be going much more in mass etc.

Already got my ducting for the project (10 inch stainless) which I recovered from a skip at work ducting.jpg I just need the fecking weather to-do it :D

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Thanks for all the great comments.

Found rebar in B&Q 2m for £4 so i still think i'll go down this route.

I think this summer i shall have the pier built and worry about getting the shed later, more money you see :D

I'm really looking forward to making this pier, like Captain Chaos said having a scope setup and aligned would be excellent !!

:sunny:

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Now the only problem i shall have is the height of the pier. Also how many bags of concrete ?

Well easiest way is set the scope up in the postion you use most and then simply measure to bottom of mount and the allow a couple of inches for your bottom plate etc, how much concrete you will need depends entirely how deep you go with hole and how much it takes to fill the tube, its gona be guesswork at best :D

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Ok here is my idea.

I want the pier to be a bit taller than the current height. 3 foot just now on HEQ5 so i reccon 4 foot will do.

Set your tripod at the hight your gonna use and try it out.

My EQ6 at its minimum height is 28 inches and thats still to high for me with the scope pointing north (highest elevation) :D

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Thanks for all the great comments.

Found rebar in B&Q 2m for £4 so i still think i'll go down this route.

Well went to my local B+Q superstore today and they dont sell it :rolleyes:

Gona have to get some steel rod from work tommorow.......Damn I was ready to por today too :x

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Now the only problem i shall have is the height of the pier. Also how many bags of concrete ?

I think you've hit on a very real problem with your strategy.

From my experience, you won't know your optimum pier height until you know what shed/dome your getting. I worked out the whole package first, then built it. The result is that I've got my scope at the pretty much optimum height for my observatory. High enough to maximise my field of view, but not so high that it interferes with the roof opening or is seriously affected by winds or glare from security lights.

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I think you've hit on a very real problem with your strategy.

From my experience, you won't know your optimum pier height until you know what shed/dome your getting. I worked out the whole package first, then built it. The result is that I've got my scope at the pretty much optimum height for my observatory. High enough to maximise my field of view, but not so high that it interferes with the roof opening or is seriously affected by winds or glare from security lights.

Then when you have the optimum height you have just restricted yourself to either Newts or Fracs. :rolleyes:

My setup has two piers to avoid this and most of the time its still wrong. I'll post an image in the gallery section once the ISeeStars starts working again, can't seem to get logged in just now.

Captain Chaos

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