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Monday 14th/Tuesday 15th. I have been thinking about the big stepladder and how it could be moved nearer the wall of the larger building. That might free up some more floor space. Ideally the trapdoor/stairwell should be in the SW of the observatory floor. This is where there is least foot traffic with a big solar refractor. Particularly in the mornings when the seeing [conditions] are usually at their best.
The problem was the fixed slope [70°] and sheer size of the ladder and its handrails at 60cm wide. The huge, timber pier and its widely splayed legs forced me into a fixed position. Oh, and the need for floor joists didn't help at all.
In retrospect, I had little real choice over ladder position. Though I could have cut the joists and boxed around the new hole it felt like a fudge at the time. It might also have weakened the structure. I'd much prefer a tangential ladder but there was [and probably still is] simply not enough room.
Guess who has been worrying about setting out the [bigger] dome and the building/dome base rings? I have no flat ground. Nor covered indoor floor surface. The top of the building will be high above the ground anyway. The dome will have to be packed up for working comfortably and safely underneath. I still have the adjustable, caravan parking jacks stored away just longing for a new purpose in life.
You'll just have to imagine my wasting man weeks going round and around the last dome and the top ring of the building. Desperately trying to get them both level for absolutely smooth rotation.
Early on I bought a long length of clear hose to make a water level. Even that wasn't very satisfactory in use nor particularly accurate. Never underestimate the weight of water. The filled hose became so heavy that it was near impoissible to use until I had a proper floor.
I was endlessly packing up the dome's support rollers and then taking the packing out again. Again and again over the last two years! I used several 3m long straight edges and my various builder's levels. Including a single spot laser level. Still indeterminate results around +/- half an inch or so. Who really knows?
So, finally, I have bought the [still imaginary] dome a Bosch self-levelling 360° laser level for Christmas. This throws a bright green horizontal [and vertical] line with an inaccuracy of under a millimetre. Not their most expensive model by far. Because the Pro models run into very silly money for a mere, amateur, project builder. I only needed a continuous, horizontal and vertical line within a range of a few meters. So I bought the Solo head alone as I have umpteen tripods anyway.
I shall be able to use the level to set out the rollers on the expanded building. As well as checking the plywood base ring for truth. This will be bolted to the rather small, moulded GRP, dome flange. To act as a wider and smoother track for the supporting rollers to run on. Not to mention my friction roller, crank-driven dome rotation system. Always within easy reach of my imaging chair. I don't even need electrodes applied anywhere for the dome to move effortlessly.
The new dome has unusual, external, upstanding joints. Which also have to be bolted together to make the three segments into a solid, white hemisphere. So, as well the usual silicone sealant between the flanges, I could apply a flexible, inverted U-profile. For cosmetic neatness and improved weather proofing of the flange edges. Which will only be partially covered by the shutter[s.]
The concrete anchor blocks turned up today. In a vast, [but empty] articulated container lorry! No way to get that thing down the drive! The driver was just able to get the pallet off the road and onto the start of the drive with his pallet truck. Then I parked the car trailer alongside. Followed by 12 x 35lbs dead lifts off the low pallet and into the trailer. Only two neighbours needed to pass but there was just enough room for their cars. Now I need a rest!
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