7.01.2020 Any colour you like as long as it's green?

 *

Thursday 7th overcast as the thin snow melts.

I have previously mentioned my wife's dislike for white domes dominating the garden skyline. Which raised the possibility of "local resistance." White is traditional. It reflects the sun's heat and maintains a more even temperature. Or does it? See below.

At which point a green dome raised its head during an image search. Which was duly spotted and remarked upon in positive terms by my wife.

I can certainly see what the good lady means about white domes. The plywood dome was lightly covered in snow at the weekend. Which made it stand out like a sore thumb from the road at 200 meters and well beyond. 

It screams "LOOK AT ME!!!" from afar. Particularly against its dark background! Though, fortunately, a tall hedge and a barn lie in the foreground. Helping to hide the rather unexpected shape in the landscape at certain viewing angles.

Agritech.Srl have been making fibreglass silos in Italy since the mid-80s. Their range of GRP animal shelters includes the dome-shaped Spheribox shown here. An ideal observatory, dome donor?

The claimed dimension are 4.3m Ø x 2.18m high [14' 1" Ø x 7' 2" high] and weighing 220kg for the bare GRP "dome." Three, horizontal segments make up the hemisphere. With bolted together, overlaps on the upper segment providing weather protection from rain run-off. 

No raised, exterior flanges, nor seams. Which gives a smoother appearance than the Holm & Laue. The horizontal segmented, surface texture is considered rather attractive by those who matter. Because it helps to break up the otherwise, uniformly smooth surface. Providing a whole range of colour shades from its multiple reflections with the sky and surrounding trees. See the stock, Agritech images here.

Making it far more "stealthy" when seen from a distance. As is my present dome with its trapezoid panels tilted at various angles to the sky. Though in this case the sage green paint is now largely matt. The temperature of sun facing, plywood surfaces literally soars! 

Agritech also do a white finish, domed calf shelter. For anyone who prefers this [modern?] traditional colour. Both colours are claimed to be strongly solar reflecting. To protect the housed animals from overheating in hot sunshine during heatwaves. Everyday experience suggests that the white finish would reflect more heat. Though this will depend entirely on the absorption coefficient at the frequency of the incoming, thermal radiation. 

The same applies, of course, with heat radiating from the dome's surface. Which leaves one wondering about the thermal qualities of wood lined, antique observatories with sheet copper roofs. Perhaps this is where the significance of "dome seeing" became established?

 

*