New Pulsar Observatory

[Silent Running]

I'm currently setting up my new 2.2m Pulsar observatory dome in the back garden. My research for this involved reading various threads hee on SGL together with visits to four other Pulsar dome owners: two 2.2m and two 2.7m. It has been a very interesting experience, and I'm so grateful for all the advice and tips from these different sources. Steve from Pulsar has been quite helpful too. I do wish though that the assembly instructions were more detailed. A series of step-by-step photographs would have been very useful. The hardest thing I found was getting the assembled walls to be a perfect circle (or close as possible). 

But I'm getting closer to finishing: concrete base with conduits set into it was finished a few months ago. After sealing the concrete, I laid a 3mm rubber sheet over it, then scribed a series of concentric circles to assist positioning of the walls. Myself and a friend assembled the dome. Two people are essential, while three make it simpler. Four of us made lifting the dome onto the walls easier. Afterwards I cut away the rubber under the walls with a stanley knife leaving a compressed rubber gasket. I applied sealant to the outside of the gasket. So far it has been completely waterproof. The Pulsar pillar is now installed. I'm currently waiting for my electrician to run power cable and ehternet cable from the house.

Last night was a real thrill, pressing the shutter button and watching the shutter open to reveal Polaris. I wanted to set the home position accurately to the North, but clouds rolled in while I was still making some adjustments. Tomorrow night looks fairly clear! Fingers crossed

[GordonD]

Looks great.

Did you lay the base yourself, and how did you get such a clean circle for the concrete?

[Silent Running]

Thanks. It seemed more tricky, at least for me to put it on the stone paved area.  I had seen postings for bases put on lawns where posts were hammered into the grass after digging out the earth. Not sure if the solution we came up with was the most efficient, but it semed to work. Under the paving stones was a layer of concrete and then hard packed rubble. For the central block I dug down through this into the earth below. I had decided not to separate the central block from the rest of the base. Basically with the help of a DIY friend, we made a square frame, put 4 triangular pieces of plywood at the corners, then scribed a circle. We then hammered in short batons of wood to buttress the curved thin plywood walls. The thin plywood bent easily to form the curved shuttering. I put down the blue plastic damp course. I set 3 plastic pipes into the concrete for future power and ethernet and anything else. I got a contractor to pump in the cement.  It was concrete mixed with glass fibres for reinforcement, so not needing steel rods. We put up a tent over the concrete to protect it from rain. Then laft it for about 2 months, while waiting for the dome to arrive.

[Silent Running]

Trying to improve weather sealing by application of a silicone wetroom  floor barrier strip to under side of dome... thanks to Mark for this idea.  Still waiting for power to dome. I need to paint the edge of the concrete base too!

[Shed9]

For reference to others seeing this, I've laid three round dome basis in the last few years, those cheap framed paddling pools work a treat, hold the concrete well whilst setting and are suitbly sized.  I've also done something similar to the method used in this thread and have to say it gives a much cleaner look in the finished concrete but the pool method work well also.