23.07.2021 Shutters and ribs.

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Friday 23rd 67F overcast and calm. The dry weather continues until later on Sunday. When several days are forecast to be wet.

The shutters remained safely in place overnight.

This morning I added more slit cross braces. With the zenith profile attached to each. This helped the shutter covers to assume the correct, spherical relationship. It was comforting how the newly parallel gap between the shutters closed up.
 

  An internal view of the shutters and 2x4 cross braces.

 There is no particular spacing. As all the braces will be removed once the   shutters are completed.

 The dark plank shown is supporting the top of the dome to avoid sag during this vital construction phase. The wide angle lens has distorted its uprightness.

 The folding, builder's stepladder is a vital tool, within the dome, to reach the   zenith. At 4.3m in diameter the dome height is 2.15m + skirt packing for level on  the uneven ground. Say 2.3m average or about 7'6" in old money.

Using the 360° laser as a guide I marked the bottom of the second shutter. Then cut it off with a fine tooth blade in the jigsaw with the shutter in situ. 

The second shutter then settled more naturally on the stack of timber I had arranged at the doorway.

The bottoms of the shutters are now much tidier. These should also follow the spherical form. So I will need sturdy radius boards for the drawer slides to attach to. Probably lots of laminated birch plywood.

The next step is to check the required radius of the shutter ribs. These will eventually be joined by horizontal ribs between the shutter's vertical ribs.

I tried a shutter rib mock-up. Then went ahead and router trimmed all the arcs to 227cm external radius and 215cm inside. 

The sun has finally come out though it remains rather cloudy. Worth a try at imaging? Probably not.

Two hours later this as the best I had managed. Boiling and soft on the monitor. Soft and featureless after AS!3. ImPPG and PhotoFiltre7 rescued what little there was hidden in the mush.

 

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