28.07.2021 Two more ribs and then a 20 minute, thundery cloudburst.

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 Wednesday 28th 68F, bright start then overcast and windy. 

My wife has pointed out that time is passing. It will soon be too cool outside to do any glass fibre work.

I had been wondering how to support the heavy shutters while I attach the [heavy duty] drawer slides. Then it occurred to me. I need a simple scaffold on each side of the dome. This will support the tops of the open shutters on a long crossbar over the top of the dome. Then I can screw the drawer slides to the outside of the zenith board. The slides will already have been attached to the shutter's top boards.  

I had an awful struggle fitting the shutter slides to the plywood dome. It was already raised high on the building. So access was only possible through the open slit from a ladder inside the dome. At the same time I was still building the shutters in situ! 

This time I am determined to have the shutters mounted on the dome before it is lifted into place. They will be thoroughly tested while reasonable access is still possible from the ground. Though even here it is a ladder stretch and then belly flopping on the dome.

Now I need lots of short 20mm wood screws for gluing the ribs and base ring. Plus some more birch ply for the zenith boards. 15mm might make more sense than 12mm for this purpose.

So I bought two sheets of 15mm birch ply and some more screws for gluing arcs into ribs.

15.00 Now I am back in the observatory. Windy and fast moving plates of cloud from the SW. With light sprinkles of rain. Still waiting for my first capture of the day.

15.19 & 26 First captures. Uneven brightness and off-band.

I completed gluing the two, central shutter ribs later that afternoon. 

It was lucky I tidied everything away because there was a five ten 15 20 minute thundery cloudburst starting around 7.25 pm. One, small window had been left open upstairs. To help to cool the day's warmth. A fierce gust caught it and whipped it wide open. No harm done and I was sitting at the window at the time. It sounds as if the bad weather is still coming over. With even louder thunder and more flashes of lightning. The DMI's radar map suggests we could get a full half an hour of this! I'll update later if it continues. The deluge eased off after 20 minutes but it continued raining.

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