14.12.2020 Footprints all over.

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My latest thinking is that I should move the centre point of the larger building to the WSW. This will avoid the need for large quantities of gravel to make up the low ground to the north. Where the ring of concrete foundation blocks will need firm ground in which to be buried.

This is also the most difficult area to reach with a wheelbarrow. Which has to be steered around the octagon on a rather narrow path. With [untouchable] oak tree stems bordering the existing pad. My wife grew red oaks with very large leaves from acorns. The observatory came later. 

The remaining, slender oaks now tower over the existing dome. They do no harm and I have no interest in the northern sky. Much larger trees soar along the northern and western borders of our rural garden. It would take a team of professionals to deal with them safely. So they are left to fend for themselves. To provide an attractive backdrop and windbreak.

I should probably use the existing NE post of the octagon as a fixed, reference point. To be incorporated into the new structure. Around which to rotate the larger, circular footprint [via the arced templates] to maximise efficient ground use. The situation is rather like a large hula-hoop. One which can be rolled around the octagon's base at will. While remaining in contact.

The centre of the new dome will only move about 18" or 50cm from the original. I am using 4.2m as the new building diameter. This will provide a 100mm overhang of the dome's rim over the new footprint. 

It is obvious that I cannot dismantle the structural elements of the old dome before the new posts are safely in place. These must take over the load bearing and be tied into the original joists. Fortunately the veranda joists are just extensions of the main observatory floor. Some creativity may be needed to bridge any gaps.

The pier will also need to be moved to the centre of the new dome.I plan to rotate it to align with N-S. Something I overlooked in the original dome because of the need to keep the southern doorway clear.

The area of gravel in an arc from the west right around to south-east of the octagon is the most stable and well established. While the ground over the northern arc falls away and has by far the least exposed gravel pad width. Requiring much larger quantities of gravel to bring it up to a useful, building pad level. 

I have considered using field stones to reinforce the sloping edges of the pad at a later date. With luck, this common agricultural "nuisance" material may be the cheapest bulk option to provide improved solidity. At the cost of considerable physical effort. There are several large heaps of stones collected from the fields in the area. Easy access from the road too. If I can get permission from the farmer.

A disappointing trip to the local gravel man as he was not at home this morning. I will ring him later to confirm when I can collect another load of gravel.

I have had confirmation of my order for the concrete foundation blocks. Delivery is now for tomorrow 15th. With a warning that the near 500kg, loaded pallet might be left at the kerb. Over 200 meters away! I have emailed them requesting home delivery and had a positive response.

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