Time for a new Obs!

[SnakeyJ]

Enjoying the glorious sunshine, with a little garden DIY.   I've brought in the materials for the patio and pier foundation and spent just over £ 200 before buying in any material for the obs itself.    The materials should be delivered tomorrow morning.   The patio tiles are a bit smaller than planned at 450mm square, so I've gone for 25 to make a square of 2280mm (allowing 8mm joints), which should be just wide enough!

Quite a bit of levelling left to do, but using some of the soil from the pier foundation to make a start.    Once I'm nearly there I will put the geotex down and put a couple of inches of sharp sand and cement as a dry mix and point it in with proper cement.   The garden side will have a low brick wall retainer, slightly over layed by the stones for a step up.

The pier foundation will be 600mm diameter by 800mm depth - just need to get some threaded bar and rebar wired up now and will do the pour tomorrow.

[Gina]

Lovely weather for outdoor jobs ATM   Preparing the ground and digging the pier base hole was the worst part of my obsy build.  The sloping ground didn't help

[nytecam]

Cheers John, a good lot the local FC, but I do get to kick a few balls back over the fence.    Ball protection is definitely a consideration!

The neighbouring pitch doesn't seem floodlit - yet :-)

[kirkster501]

Lovely weather for outdoor jobs ATM   Preparing the ground and digging the pier base hole was the worst part of my obsy build.  The sloping ground didn't help

Isn't it just?!  Got loads of concreting jobs done that I needed to do.  And shortly the best one of all, digging out for the pier :)

[SnakeyJ]

The neighbouring pitch doesn't seem floodlit - yet :-)

Now let's not be too pessimistic - I am on the committee for the FC, so will at least get the heads up :-)

[ollypenrice]

Here is a different approach as I have the same problems like you... Rented house and and long setup time for the gear. As the winter was long and cloudy I have played around trying to find a solution. This is the result, its for imaging only and I call it RoRoToGo

RoRoToGo.jpg

The idea behind:

Max cost of 700€

Quickly removable without leaving a trace 

The shed:

• As you can see the whole shed is moving.
• It sits on on bricks which are laying on a bed of gravel.
• Bricks are held together with some steel rail on which the wheels are rolling.
• Floor is made of concrete slabs layiing on gravel
• All four walls have the same size, e.g. 2 x 1,8 m held together with metric bolts and nuts
• Roof sits on a frame also attached to the walls with metric bolts and nuts for easy disassamble
• Walls are clad in shiplap (hope thats the right word)
• The lady in the right is 179cm tall

The foundation and pier:

• Top surface of the concrete foundation lies lets say 20 cm below ground level for easy covering

  with soil when all the stuff has to vanish

• Pier is made of a wastewater pipe, 20 cm in diameter
• On the bottom of the pier is a metal plate which is screwed to the foundation for easy removement
• Pipe is filled with concrete or sand... don't know whats better..

Foundation.jpg

Hope its understandable what I wrote. Have not built this and I confess there are some more details to work out but maybe it gives you some new ideas.

Cheers

Martin

This is what I would recommend and I've built two of them - though I used a welded steel chassis because the structure is fundamentally flawed since it is a cube lacking one of its 'lines' - the one at the bottom of the opening.

Since building my two versions lots of folks have come up with the best solution. Install a pier (mine were designed for tripoods) and make a plywood base running on rails up to that pier and away from it. Then bolt a bog standard, thoroughly nasy plastic B and Q shed onto the rolling plywood base. FOr a nicer version you can use a nicer timber shed. See SInglin's observatory.

Olly

[SnakeyJ]

I had a good day yesterday, sorting out the levels, adjusting for the smaller slabs and building a small brick retaining wall. The weather was glorious, but the old back was a little niggly by close of play.

Today is equally nice, but work on hold while we take Sophie for treatment in Southampton.

Hopefully tomorrow I can get the pier footing in and the slabs down.

[Gina]

Hope Sophie's treatment well Jake

[SnakeyJ]

Hope Sophie's treatment well Jake

Thanks Gina, we're just on the boat home now. Still a little patchy fog on the solent, but otherwise calm and warm. Sophie's munching hula hoops and bossing Lou and I around. She's definitely up at the mo ;-)

[Gina]

Oh that's good news Jake

[SnakeyJ]

Getting back to work today, but going gently as the back is still a little niggly - might excuse myself the concrete mixing today

Site levelled, geotex down and I'm laying the slabs on a dry mix of sharp sand and cement, though once I have them levelled and the fitted around the mount, I will relay the edge stones on a wet mix and point in the with cement.

I really love the practical and physical side of a light building project, though the brain will get more of a challenge in the next phase of the build

[SnakeyJ]

Not quite as far as I planned to go today, but I did get the concrete mixed (by hand) - apart from the complaining of abused/seldom used muscles and the back, I feel in pretty fair shape and will sleep well tonight

I only managed to lay 11 slabs, but had to do some adjusting of the spacing to get them to fit nicely with the centre tile positioned over the mount.    I used an old kip mat to wrap around the edge of the pier foundation, this should provide a little  isolation from vibration as I walk around the pier.   Just need to level off the top of the foundation, so that it is level with the bottom of the slabs - this way I can grind the bolts off and drop another slab in to hide the concrete when we move on.

Should get the rest of this finished off tomorrow and will then have a tidy up before starting the build proper

[SnakeyJ]

Well not quite finished, child care trumps construction!   Thought I'm now within an ace, with perhaps 6 hours left for some fine levelling and grouting in of the paving slabs.     Weather permitting I can get this done next weekend and then order in the plywood and start work on the observatory build.    I'll try and get some drawings up this week for comment and refinement

[laser_jock99]

I would also advocate siting the concrete mass slightly below ground level and making the pier unboltable from it. Even if you own the house/garden you never know if your interests will change or you need to move the whole setup for some reason.

[kirkster501]

I've bought paving slabs, bricks for the pier and pier head mounting bits.  Should be ready to go with my build soon.  I will start a thread regarding my build then.

Your setup is looking good Jake!  I think it's wise using the weed protector I will do that too.  I was initially just going to bed the slabs on sharp sand but after seeing what you are doing here I will use a weak 7-to-1 of sand/cement -  a good idea I think.do you think such a mixture is enough to solidify sufficiently hard to support the slabs?

[SnakeyJ]

I've bought paving slabs, bricks for the pier and pier head mounting bits.  Should be ready to go with my build soon.  I will start a thread regarding my build then.

Your setup is looking good Jake!  I think it's wise using the weed protector I will do that too.  I was initially just going to bed the slabs on sharp sand but after seeing what you are doing here I will use a weak 7-to-1 of sand/cement -  a good idea I think.do you think such a mixture is enough to solidify sufficiently hard to support the slabs?

Cheers Steve,

The Geotex was on offer at my local Jewsons, I think it was 11 sq meters for about £ 12.  I put down two layers and still had a fair bit left over!   In my case this is also to make clear up easier should the landlord want me to return this to origional.

The dry sharp sand and cement does cure off slowly, with humidity and damp.   I used a stronger mix for the unsupported sides, which went in wet at around 6-1, the dry mix was probably around 7-8:1 but I only did this roughly.     If you tamp it down level with a bit of timber it will hold the slabs level nicely and can be done very quickly.   

[SnakeyJ]

I really must learn how to use sketchup for this, but just can't find the will power at the end of the day - especially if the sky is clear.

Here's a very rough plan, wrestled from Visio which is not the most useful design software.

First up a plan view giving approx dimensions and the main structural components.

The blue ring will be made up of 8 overlapping 90deg arcs cut from 12mm ply and glued/screwed together.   Nominal outer diameter will be 2088, with a 6mm by 100mm ply skirt making up the diameter to 2100 and providing an overlap over the dome base to keep the wind and rain out.    The two vertical red lines are full 180deg ply arcs made from 12mm ply (as I can only cut one of these whole from a sheet, I will look to refine this and it may be a composite piece).    This will ultimately form the aperture opening of approx 550mm (want to allow for a bigger aperture and mount in this calculation) and take a raised edge rail for the sliding shutter (still being mulled over).    The two short red horizontals  In between are cut to will probably have be curved to the sectional radius.  The other six red radial lines will be cut to size from full 1050mm x 90deg arcs.   

Grey thick circular lines are a heavy duty 32mm diameter plastic conduit, which I have as a scrap material.   These will be hole cut to pass flush and square with the edges of the radial frames, but I will need to make ovals for the conduit to pass through the two hemishperical frames framing the dome opening.  The conduit  should run around and maintain a nice circular dome profile for an outer skin, which I think will be canvas painted with two part epoxy paint - this should be easy to work, light and importantly cheap.

Side view of the dome only (with 100mm skirt added).

not much to see on the side view other than the frame width which is nominally 100mm and can probably shrink and a rough section showing location of the conduit.    More concerned with the asthetic than strength here, but the frames should be in compression and can be glued around the conduit.    Where the conduit ends at the shutter frames it will be dowled and screwed to hold in place.

I will run the dome on inline skate wheels recessed in to the top of wall not shown and will probably try a friction drive system to match sidereal rate (driven by motors within the wall.    Shutter opening will be manual to keep things simple for the time being.

I'll probably add some tie down points in on the apex of the shutter frames to give some security against wind and forced entry.   I will have a low entrance door in the base wall - duck and crawl through.

Base wall height probably around 1.2m, giving me 2280 or there abouts above the patio.    I might drop this a little once I've measured the pier and mount options.

[Gina]

WOW!!!

[SnakeyJ]

WOW!!!

Thanks Gina - but you'd better save the wows until it's built, up and running!   No shortage of ambition, but both money and time are limited

The budget so far stands around £ 220 for the materials so far, but I'm aiming to get this in for under £ 500 and the ply will put a large dent in what's left.   Though I'm not counting the automation or after mods!

[Gina]

You sure are an optimist Jake   Good luck

[SnakeyJ]

Finished and pointed in the slabs this evening - not perfect, but good enough. Just need to level off the top of the pier footing, ready to take the mount.

I'll get the ply in next week and start playing ;-)

[SnakeyJ]

I got a little carried away with the landscaping and decided to add a little path to the side of the patio - just needs another bag of gravel to complete this and a few touches to the pointing.

The spare slab at the back is reserved for converting the obs base back to a plain patio, when we move on - I do hope the owners appreciate all this effort!

[Dave Lloyd]

If you do move out I can't see anyone objecting to what you've done. I reckon it will add value.

[Gina]

Agreed.

[SnakeyJ]

If you do move out I can't see anyone objecting to what you've done. I reckon it will add value.

Agreed.

Nothing ventured and all that  At the end of the day it can all come out and be re-instated reasonably easily - less the pier foundation that would be buried/concealed to confound the archaeologists in another few hundred years   A primitive altar for pagan sacrifice perhaps!