Introduction
This series of articles will chronicle the process of building a permanent astronomy telescope pier in my garden. A permanent pier makes the setting up process for an night of astrophotography or visual observing far less laborious. This is because the pier is already aligned with the celestial pole, via the North peg on top of the mount adapter. Power and network adapters are immediately to hand, removing the work of laying cables out from the shed and putting them away later after each observing or astrophotography session.
Cutting the Turf
Well, I had to start somewhere, so I decided to cut a trench to the site of the pier as my first step.
Turf cut back where the trench will be dug
The trench is approximately 50 cm deep, keeping the cables far enough underground to be out of the way of anything that might happen in the garden. Thankfully the ground here is light soil and rock-free, therefore quite easy to cut into.
Installing the Cabling
The next step was to get some cables into the ground. I acquired some red polypropylene cable conduit, with an inside diameter of approximately 27 mm to act as a waterproof path for the cable from the shed to the pier.
Red polypropylene conduit laid out ready to be placed in the trench
The conduit carries three separate cables: a 3.0 mm2 33 Amp twin core 12 volt automotive cable, a 2.5 mm2 twin and earth 240 VAC mains cable and a Cat 5e network cable. These will all break out into waterproof enclosures mounted on the side of the pier.
Trench cut into the path at the side of the shed
As can be seen in the picture above I had to cut a trench into the path at the side of the shed to get the cables into the building where the services are. Being that the concrete was old (25 years +), it was very hard and took a long time to get through.
Cables entering the shed
The cables enter the shed via a waterproof electrical box. This will make access to the conduit easier should I need to add another cable one day; highly unlikely, I think. Having the box there also avoids having to make a difficult 90° turn from under the path into the brickwork.
The pier site with the conduit in place
At the other end of the conduit lies the pier site itself (of course!). At the moment there is just a large hole ready for the concrete pour and a lintel where the base of the pier will fit. The conduit emerges near the base of the pier site and it will then turn 90° in an upwards direction, going up inside the pier in order to break out near the top.
What's Next?
Next comes the building of the pier itself; the plastic pipe for the pier itself, pier head mount adapter with associated metalwork and the breakout box for the electrical and network connections. At this stage the weather has intervened, so everything is sitting waiting for the rain to pass.
As usual, all outside projects are subject to the vagaries of the rather changeable British weather.