17.6.21

17.06.2021 Heatwave Day1.

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Thursday 17th 75F at 09.40.  The sky is softly white and rather cloudy. I'm wondering whether it is worth setting up for solar imaging.

The Titebond III glue which I ordered from Amazon.De has got lost again. 6 days since it was handed over to a "Subcontractor" by the Austrian Post Office. No name and no updates. 

The only stockist of Titebond III in Denmark, with claimed stock, is with the same business which still hasn't supplied the router bit I ordered. Probably two months ago now. 

None of this is helping me build the laminated plywood ribs. The arcs are cut out and trimmed but remain in stacks awaiting wood glue.

10.10 77/75F My first images, of the day, were based on a 912x912 frame and remarkably evenly lit and detailed. My PST has a distinct "sweet spot." Which is exaggerated into dark and light areas by larger frame sizes. 2x GPC.

 

 

11.47 A close-up of AR12833.


12.20 83/80F [In/out of the dome] 

 

 I have closed SharpCap, closed the dome and slewed to the parking place to try and cool things down. It is proving impossible to improve the sweet spot. SharpCap reports 48C for the ASI174MM camera temperature.

 

It reached 84F in the shade in the afternoon. 86F in the dome. Too much for me with the dome radiating heat inwards! After checking the temperature of the inside of the plywood at 120F I stayed away until it cooled off. 

The green GRP dome measured 130F, inside and out, perpendicular to the sun. As I have said before: The shutters are facing the sun when I am solar imaging. Which means that the dome is quite well shaded by its own shutters when they are open and facing the sun.

It also means that only the shutters need to reject solar heat. So in summer it should be easily possible to drape strips of white material temporarily over the [green] shutters. Perhaps using hooks at the top and bungee cords at the bottom of the shutters to maintain tension? 

Lightweight, white tarpaulin would last long enough to be useful and seems to remain nicely cool. If it were held flat and taut it should not be bothered by the wind. The back of the dome could be presented to the south when I was not actively imaging.

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