Observatory is getting there
I’ve got the roof on now! with some help from my friends.. going to get the walls on this week before I head off for to aussie for a couple of weeks.
Here’s how it started.
First of all, post holes were needed – 900mm deep in fact, then the posts were cemented in. Took a bit of time to make sure it was all square. Using Pythagoras’s theorem (a2+b2=c2) the diagonals were measured to ensure the angles were exactly 90 degrees, this resulted in a perfect square. Most other methods I tried ended up as a parallelogram! The beams at the top and bottom were to ensure that the posts remained vertical and didn’t move.
This was the tricky bit – the concrete pad!.
First of all the hole needed to be dug, 1.2m x 1.2m. I figured it had to be around this size after measuring the distance of my tripod legs and allowing for extra extension. The depth was 600mm.
The framing was constructed and sunk into the ground with posts for strength. The top piece of wood going all the way around was designed to come off easy.
The base was filled with Gap 20 gravel and compacted it as best I could with a heavy post (couldn’t get a compactor in there).
Then the concrete… this was a mission because the concrete mixer wouldn’t fit past the gate!, the wheelbarrow was used to move it all to the pad which was quite heavy work. The job took all day, and I was exhausted afterward!
The top piece of framing timber was removed, and the cross beams were put on. I notched them so they fitted into each other for extra strength.
The plywood floor was put down. I used 17mm Marine ply for this.
The storage area at the side was built, this required a couple more posts to be concreted in.
I rounded up some crewmen for this mission, 8 of my good friends helped out to lift the dome onto the base, then we had a few beers and a sausage sizzle!
The dome was quite heavy and a bit awkward, but the mission was completed and we had an awesome day!
Now I’ve just got to get the walls on!