The post

The support post for the telescope really needs to be thought through. You need to consider ground level, floor level and what height the telescope needs to be to view the horizon through the very bottom of the dome slot. My Celestron SCT is quite heavy. When and if I start to add CCD imaging equipment to it and then counterweights, on top of an equatorial wedge, the post required to support it will need to be quite sturdy. All the best astronomy equipment is useless on top of a flimsy mount. I only hope what I have made is sturdy enough. If not, no worries, I will just have one more challenge to build a bigger one!

I started with a lot of sketches that evolved every time I drew it again. The final design involved no turning, and very little cutting. I asked a site office at a construction site if I was allowed to grab a couple of their water-mains off-cuts. They were happy as long as I showed them what I took before I left. The post comprises of an inner-post and plate, sliding and rotating inside a larger diameter outer-post and base plate. Mostly welding for this job. The wall thickness on the pipe is about 4mm and the plates are 10mm thick mild steel at about $5 each. For the adjusting screws I drilled 12mm holes then reamed them out a little, then welded on 12mm nuts over the holes. Make sure you have the bolts screwed in for this in case of heat expansion.

I had to modify this again later as the height proved to be 20 inches short, so I found a longer, thicker pipe and welded it straight over the top of the short, thin one.

I had my cousin modify my equatorial wedge, so that I no longer have to lift and support the telescope while I adjust it's angle. Now I can wind it down with great accuracy and control. God bless you Ray!

Post/Pier MK II

During the dress rehearsal stages, I discovered that the post design was ok, but its sheer length made it impossible to stop it from vibration. Time to re-think and go for a solid concrete pier.

I glued (Liquid nails) and screwed a 2.4 metre by 300mm tall box together using 16mm chipboard. Next was to weld some RIO together to fit inside the box, ensuring that there is a way to weld on mounting bolts on top when done, and to be able to weld it to the steel poking up out of the foundation block mass

I also ran some twin and earth through the box, and pre-positioned a couple of double power points on the box. I am leaving the wood on the pier once it is filled with concrete, then I can sand, paint and fit things to it later if I get any other bright ideas.

I lowered the whole thing in through the hole in the floor and temporarily propped up the box high enough to get the welding rod underneath to weld the RIO to the existing foundation bolts, originally used to anchor the post.

I then dropped the box down fully and places three truck tie-down straps around the box, as a precautionary maesure, to hold it together while the pressure of the wet concrete builds up. Once set, the straps can be released.

I constructed a top plate out of 300mm x 300mm x 10mm thick steel plate. This had four holes, one in each corner to bolt to the top of the pier. I then cut some curved slots in it that correspond with the mounting holes on the bottom of my wedge mount. This will allow rotation to properly align the scope. Make sure you trial align the plate to south with a compass or with the stars to get the rough orientation right in the first place.

The next step, is to prepare the mounting bolts. I cut some lengths of threaded rod and placed them through the holes in the corners of the top plate. Then screwed a washer and nut either side to pull them straight. Next, place a spirit level on top, and lower it down onto the RIO you should have in the pier box and ajust the threaded rods, winding the nuts up and down until you have contact on the RIO, then weld in place. Yes you have to leave a gap to weld under and to get a spanner under for later. Once the threaded rods are welded securely, unscrew the top nuts and remove the plate.

You are now ready to pour concrete in, all the way to the top, level with the top of the wood, leaving the threaded rod exposed for mounting the plate later.

I screwed some positioning battens down to hold the pillar in place while I poured in a strong mix of concrete, bucket at a time. In through the top.

Once the concrete has set, hook up the power to the wire you left hanging out, remove the battens, dress off the hole around the pier with some mitred skirt, then sand and paint the lot.

Let the fun begin mounting and aligning the 'scope!

Viola!