6.11.2021 Wet and windy. Base ring brackets.

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There won't be much progress on the dome today. Wet and windy. 

I could fit the remaining shelf brackets to the base ring. That would be mostly inside work out of the rain.

Which is what I did until lunch time. I used the 360° laser level again. Just to confirm the base ring was still level. There is no point in making it wavy. By bolting it to the multiple brackets without checking first. Being able to check the ring to within a millimeter, or two, builds confidence in the accuracy of my work. This earlier image shows the general idea.

I have wasted the equivalent of countless man days in trying to level the plywood dome. Which I built a couple of years ago. There is no certainty of level using builders levels and long straight edges. I even tried water levels using clear hose. That was an exercise in pure frustration! 

The laser level told me the levels instantly. The moment I turned it on. The plywood dome has spots where the rollers are no longer in contact with the underside of the base ring. Which puts greatly increased loads on fewer rollers. 

The advantage with the fiberglass dome and ring support brackets is fine adjustability. If necessary, I can place packing under the brackets individually to help to flatten the ring. I can also use the 360° laser level to make all the rollers exactly the same height. That makes it a very powerful tool for observatory building.

After lunch I completed the last of the [31] shelf brackets. Spaced at 33.5cm centers they are supported by plastic wedges and large washers against the dome's inner surface. 

Allowing for 500kg all up dome weight that is only 10kg per bracket. They are rated at 65kg using wood screws. My use of pairs of 10mm bolts in the vertical leg should greatly increase the load carrying capacity. 

These brackets are not alone in resisting the weight of the dome. As mentioned previously, the loads are spread through the slit ribs, zenith and base boards. I am seriously thinking about adding [angle] brackets to reinforce the slit rib connection. The fiberglass provided some mechanical support but adhesion is poor against lateral forces. I need a bracket long enough, in both legs, to keep the bolts well clear of the slit ribs. The overhanging shutter ribs have no clearance problems.

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