3.08.2024 Will the real Pulsar dome please stand up?

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  Saturday 3rd. The very high cost of owning a Pulsar observatory made me wonder. Whether I could improve my present but very leaky 3m dome. The plywood surface badly needs to be sealed. Particularly at the joints.

 I could have the local crane hire lift the dome down onto blocks. Where I could safely fibreglass over the plywood. This would add even more weight. Though I would able to work on the shutters from the safety of the ground. They need attention after years of exposure to the weather. Access is presently difficult, dangerous and very exposed. While the dome is in situ on top of the two storey building. 

Once I have the dome waterproof and cosmetically acceptable again. It could be lifted onto a square building in the front garden. Fiberglass layup is a smelly, expensive and time consuming pastime. The resulting dome would be rough on the exterior from the chopped strand mat. Sanding would not improve the surface finish by much. GRP dust is horrible stuff! Itchy and probably dangerous to inhale. A really nasty job. 

 One option would be to buy aluminium sheet. To replace the warped plywood covering panels. This would require very careful bending to match the geometric forms. None of which are exactly the same size! One might as well build an aluminium dome from scratch.

Then there is the "Todmorden" barrel dome. A sort of rotating Nissen hut with sliding sections. To provide the opening [observation slit] for the telescope to see out. This has the advantage of providing lots of room for the telescopes to swing inside the "shoulders" of the protective structure. It can be built of aluminium or [probably] plywood. Having so few joints, compared to a hemispherical dome, should make it more waterproof. A simple lap joint at the roof overlap will prevent rain from running straight inside. There are numerous illustration of their barrel domes on their website.

 https://www.astronomycentre.org.uk/

 Another alternative is to buy just the Pulsar dome on its rotation, base ring. This would be lifted onto a square, timber and plywood box building in the front garden. Saving about £1370 [equivalent] over the purchase of the full height, Pulsar observatory with walls. I'd have to do some checking to get an exact figure. The freight charges might be a bit lower too. 

 The dome-only option from Pulsar. They have some considerable confusion over their dome illustrations online. This is probably the 2.2m. There are too few rotation roller brackets visible for it to be a 2.7m. The usual drop down flap, at the bottom of the observation slit, is missing. Perhaps suggesting a Mk2 dome? 

Who knows? Pulsar doesn't seem to. Most of the international website sales illustrations are for the earlier domes. So anyone ordering one without doing some homework will be very surprised at what eventually turns up! Even Pulsar themselves are showing the two sizes on the same page on their website!

 I have loads of materials to build the walls for a square box base. No additional equipment bay would be required. Since a square box provides lots of extra space in the corners compared to a plain cylinder. A dome-only purchase might need only one [very expensive] pallet. I would have to inquire of the European dealer. 

 There are always cons: A square, box room base would fill the front garden far more than a cylinder. It would also block the light to at least one living room window and to the greenhouse. Squeezing between the building and the greenhouse would be far more difficult than walking past a smooth cylinder too. The grooved plywood I use for cladding is too stiff to follow a curve. Though it might be made to do so with tensioned, ratchet straps.

 

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