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Tuesday is another wet day. In between showers I removed
the 180mm telescope [7" f/12 refractor] and saddle from the mounting.
Then improved the mounting's weather protection after the counterweights
had swung down to their lowest point. One of the Skywatcher style tube
rings had a sheared hinge screw. Suggesting I need to take greater care
in risking my telescopes on these rings. The spindly castings at the
hinge do not inspire much confidence either. Drilling these out to fit
larger hinge screws [or stainless steel, hex socket head bolts] might easily weaken them!I have now checked the level of the pier relative to the octagon. The present 2x4 "handrail" [bracing] is 4cm [1.5"] above the pier's plywood top plate. With the tops of the 4"x4" octagon posts another 10cm [4"] above that level.
I still need to check the octagon post heights with a water level before adding a new, 2"x8" octagon top rail, laid flat. Eight dome rotation wheels will be inverted on top of these over the posts for support. All of which helps to increase the height of the dome to provide improved, internal, telescope clearance at the zenith. Though this will not alter the diameter elsewhere, of course.
Wednesday was another wet day. I brought back more 45x45mm timber for making longer struts but it was far too wet to uncover the dome for taking any measurements.
Thursday: I just looked out at another cloudburst at breakfast time. To see the dome skeleton uncovered by the wind. A dome is not the easiest item to cover with undersized, lightweight tarpaulins. I don't have room for a tarpaulin tent-garage in any of the sizes on offer. Since they are sold as vehicle garages they are always much longer than I need or have space for. A 4m x 4m square one might just have worked. I'd need room to move around the dome or it would have been completely pointless. My old car needs room to reverse before heading down our long drive.
Hanging a loose tarpaulin from the octagon and shed, for shelter, would not have helped much. Even if the wind had not torn it down it would not have been big enough to offer much protection. A tarpaulin over the dome itself does not provide anything useful for working on the dome exterior in changeable [wet] weather. The struts and fixing screws have to be fitted from the outside.
Today, I decided to dismantle the complete dome and store the arcs and struts to dry out in the shed. It took only quarter of an hour from start to finish thanks to Torx screws and my rechargeable driver/drill. It just wasn't worth persevering without a single tarpaulin to quickly cover the entire dome in one go.
I discovered that toe-nailing adjacent struts with screws is best achieved with round head wood screws. Countersunk [Csk] heads love to dig in and jam on the previous strut when being removed. Round head screws cannot dig in whatever the angle. Worth knowing before I toe-nail screw all the struts in adjoining gores for greater strength. I had used a mixture of screws to fix the gores together and wasted time, in pouring rain, struggling with the flat heads of the countersunk screws.
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