30.10.2021 Dome shutter progress at last!

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Saturday 30th 51F, bright start, but rather cloudy. 

10.30. Set up for imaging in bright sunshine.

10.40 Now solid, grey overcast.

OMG! This means I have to work on the new dome!

I decided to double check the shutter alignment before proceeding. A 2m straight edge was laid across the inside of the observation slit ribs. Then I leveled it. A second, shorter level checked the level of the slit base board. I measured forwards from the straight edge to the inner edge of both, outer, shutter ribs. Some fiddling with prop levels and all was well.

This gave me a reference for marking and cutting out the right side, shutter, base board. I was just able to make the board out of a bit of scrap 2x4. [50x100mm] Then I could fix the bottom shutter slide to both boards. 

Though I have yet to fix the shutter boards to the shutters. This would be premature before the final shutter heights are fixed. My 360° laser level suggests that the slit, bottom board is about an inch low. [25mm] It should rest on top of the dome, base ring.  Which is yet to be completed.

The last image shows that I could probably lower the top drawer slides. Both shutters are too high relative to the slit ribs. There should be an overlap for basic weather sealing. The shutter slides limit the shutter's outward movement.

I was finally able to open and close one shutter supported only on the drawer slides. Though it was a struggle. Neither top nor bottom boards are properly connected to the GRP shutter covers yet. Which means that the cover is not providing its own [sheet] stiffness. Which would triangulate the shutters against lateral twisting. Not to mention securing the drawer slide supports. I do not want to drill any 10mm [bracket fixing] holes in the wrong place. Although they can be filled it would just add more work.

After lunch I shall make the bottom board for the other shutter. If it doesn't rain. We were promised rain in this morning's forecast. It didn't happen. We had some sunshine instead. Then it turned dark grey and stayed that way. It is very mild for the end of October. 53F at 14.00. The SE wind is rather variable.

It duly rained at 2pm. Just as I was about to start work again. I went out a little later as the rain stopped. Finishing the second shutter base board. Fixed the slides. Then found the shutters were too low. The ribs were rubbing on the dome before they were closed. They could not be lifted because they were fixed to the slides. The base boards were fixed to the shutter ribs with really sturdy brackets.

 

The shutters would no longer close. My first guess is that the shutter base boards are too narrow in plan. Easily checked and fixed tomorrow. It is dark now and the rain has started again. Pushing me back indoors. I can unscrew the slides from the base boards and add battens to their faces to check my theory. Pushing the bottoms of the shutters away from the dome should provide the clearance now missing. 

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