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Sunday: Gales and rain. While I was in town yesterday I bought more lengths of aluminium flashing for
the bottom of the dome walls. I need to throw the rainwater further out
onto the veranda.The rain is running through the flooring, onto the joists beneath and wicking under the boards. Causing rain to run down the lower building walls. The danger being that it will run inside the walls in prolonged, heavy rain driven by the wind.
The flashing won't get in the way of my feet on the veranda. Because the dome walls are inset compared with the slightly larger dome on top. It was blowing a gale so I soon gave up on any idea of doing the flashing today. This would require loosening the plywood panels, on the upper walls, to tuck the flashing profiles underneath. Which will move the flashing 12mm further inwards by the thickness of the boards.
The image above shows the profile propped up against the front of the wall boards. The vertical "tab" along the top will go behind the boards. The nose of the flashing profile has an under-fold for extra stiffness and to ensure a clean run-off.
Some slight trimming will be required across the bottoms of the wall panels to ensure a fall across the flashing. The tops of the relevant floor joists probably ought to be chamfered to improve local run-off. Luckily I became ambitious during the build and made the veranda boards parallel to the observatory walls. This made it much easier to aim the rain away from the building. Particularly since I also gapped the boards [spaced them apart] for better drainage and to avoid the likelihood of puddles on continuously, close jointed boards.
The overnight gales managed to rotate the dome slightly away from its usual, southerly parking orientation. I should probably have faced the shutters more into the wind. I was working on the PST etalon by artificial light, while the wind rattled around the dome yesterday afternoon. Just a habit from having a desk to work on while seated. The workshop has no seated accommodation for such exercises. The light from the observation slit is excellent for fine work but obviously, not possible, nor desirable when it is raining or blowing.
A dome is a truly unique environment. One to which I have grown accustomed. Due to so many hours having been spent in there. When not imaging, I am usually working on the telescopes and mountings. Or on the building itself. Being present, so often and getting so much hands on experience leads to new ideas on how to improve the set-up. Or merely to make it much more user-friendly. Those who only rarely use their observatories might not even notice how things might be readily improved. Nor spend so many hours musing over enticing possibilities.
The counterbalanced, access trapdoor has been really quite amazing. Effortless opening and closing instead of potentially, injury-inducing misery. Before the weights were fitted I would often leave the hatch open, even in the dark,. This despite the very real dangers of a serious fall down the steep stairs. It was so hard to open against its own, considerable weight. I made the hatch out of the same, solid larch flooring as I used everywhere else in the construction. It was a heavy lift and lower!
Now I just lift the hatch with my toe until I can reach it comfortably with my hand. I could improve matters still further with a U-shaped, drawer handle. Then I could easily lift the trapdoor by hand. Without stretching far into the hollow telescope pier. I was going to use a heavy knotted rope for lifting and lowering but gave up on that idea. It would have required the rope be anchored somewhere when not in use. The counter-weighting also made the rope rather superfluous.
The hand cranked, counterbalanced, friction wheel, dome drive still works well. It is effortless and the drive ratio ideal for both small or large movements. When I spend all day imaging, the dome shutter needs to be moved on to follow the sun. The relocated, chain driven, crank handle is now beside my desk. Making dome rotation almost automatic. Without any of the cost and complexity of commercial or even DIY, motor driven, dome tracking systems.
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