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Sunday 14th. The snow clings on with more to come tomorrow. We had frosts down to -13C[6F] for a couple of nights. It was bitterly cold in the workshop and observatory. The hard frozen ground made further excavation completely impossible.
Not much physical progress to report. Other than repeated measuring and [rather desperately] trying to imagine having lots more space. It is very difficult to judge how the rough crescent on the frozen and snow covered ground will eventually transform. Into more fresh air to swing a cat, or anything else.
It is all too tempting to imagine the increase in diameter means the same increase in radius. By the time the mounting has been nudged towards the WSW the increase in radius is only about 2'. [60cm]
I will, of course, gain from a much rounder building profile. With much slimmer arcs at the roller and dome, base ring level. The octagon is/was very wasteful of useful space. The heavy timbers even more so. Straight lines cut across valuable elbow room. Making binoviewing and solar wedges too selective. In when and where they can be comfortably used. Or not at all!
It all feels rather unreal at the moment. I am not used to having to wait [so long] for delivery. This is the age of instant gratification after all. Place an order and some online dealers will ensure next day delivery. The donor, calf dome "kit" may still be a full month away for all I know. Without any idea of its physical progress. Until I receive an email notifying me of impending delivery.
It all depends on the dome being available and safely assembled within the garden. Without it, there is quite literally no new project. Meanwhile I can only imagine the sheer size and weight of the segments.
Though I should probably be grateful. For having so much time to polish my pipe-dream rehearsals. Without the physical presence I am rather stuck on exact dimensions. I dare not forge ahead for fear of a complete mismatch and the wasting of some very expensive materials. Birch plywood does not grow on trees! 😉
The workflow should go far more quickly and smoothly than the last one. Where I was literally making that up as I went along. With the expert aid of others far more practised in building work [on the astro forums.] The dome and building became an exercise in compound mitres and precision cutting on machines I had never even owned before. Now their considerable cost can be shared with another project. I just wish I had owned these machines and tools years ago.
The most vital aspect, of the new dome, is its [hopefully] guaranteed weatherproofing. The observatory contents is not designed to be waterproof. The GRP dome should overcome the leaky handicaps of the plywood structure. I can make it much more windproof too. Without the problems of the rubber skirt lifting and slapping.
The new dome is round at the base. So a round, top ring on the building should provide a much more reasonable seal. I plan to raise the base ring up inside the dome slightly to ensure run-off does just that.
The new building perimeter will no longer have exposed gaps between the joists. It seemed like a good idea at the time. To ensure reduced heat build up by providing lots of sub floor ventilation for a "chimney" effect. It didn't do much and even opening the downstairs doors had no obvious effect on the temperature differential. I constantly measured the air temperature in the deep, northern shade under the veranda. Then compared it, on the same in/out digital thermometer, with the dome's internal, air temperature in the shade.
I'd also use my laser guided, remote sensing thermometer. To monitor the dome's plywood, panel temperatures. It was obvious that the panels perpendicular to the sun rocketed. While all others would read much lower. It should be remembered that the dome was constantly rotated to follow the sun. So the same panels became hot. The shutters provided shade to two vertical rows of panels. So those just outboard of the open shutters were always hottest. As were the highest panels in high summer. When solar altitude was at a maximum. About 56° locally.
I tried suspending shade net above and below the light path across the open slit. To little, or no, obvious effect. Though it did help to reduce wind blowing into the dome.
Only a highly reflective surface facing the sun would really help to lower thermal differentials. Something like space blanket would probably work best. Though I discovered that white, lightweight, woven "tarpaulin" was thermally neutral. I never got as far as cladding the shutters with this stuff.
The dome manufacturers claim low thermal absorption on the outer coating. To protect the [more usual] animal occupants from heat stress in southern European, heat waves. Only time will tell if this valuable advantage is true. A near invisible, green dome, which also reflects solar heat, is an unlikely bonus in terms of domestic bliss!
My incredibly tolerant wife was never keen on a white dome in Her garden. Much as I'd like to think the white would be thermally "superior." There didn't seem much point in pushing for a highly visible "carbuncle." What passes unnoticed from the distant road is inevitably more secure.
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