I have clay at 600mm depth. I did a lot of reading on Stargazers and it's a common theme in England (probably plenty of other places too) and everyone says their clay is extremely stable.
Comparing Britain's temperatures to Lithgow, well, we don't get as much rain, occasional snow and -12C at night through winter.
1.3 M^3 would be a lot of concrete for me to mix and I wouldn't get a truck into my back yard, bags would cost me a fortune.
Add rental (department of housing, I'm not leaving till I drop dead or win Lotto and I have the strangest feeling I know which will come first). That's why I wanted something easily disposed of to a certain depth.
I already own the pier and since I bought it I'm determined I'm going to use it. I was going to weld my own up and have everything here to do it but a great offer came up locally.
I did just look up the concrete pads Bunnings sell:
https://www.bunnings.com.au/anston-6...-slab_p3451565
I can easily stack and drill 3 of them to add the extra 150mm height, removable in the case of my leaving this plane of existence, death or big win, run my stainless threaded rod through into the concrete pad (set during the pour) and the pier and nut tension would hold them in place on top of a semi decent concrete pad tied into the ground with the radiating reo bar driven in to around .8-1 metre diagonally at 30 odd degree angle.
Alignment is always an issue, I am just beyond the mountains and can't pick up stars as easy so I generally forego it and rely on a good solar noon for south and currently markers on 3 pavers set level in my sloping yard.
I obviously haven't gotten to anything beyond 180 second exposures as of this time but hoping a permanent pier and more permanent set-up will allow me a little better. Plus I would put more time into getting accuracy suitable for my low level of equipment.
I can drift align possibly but besides the mountains to my east I have trees everywhere surrounding my yard ( immediate neighbouring houses) at around 30-40 feet high. It used to be so much better here before I got so old and the trees grew so high.
I keep telling everyone I should sell everything astro related and buy a motorbike I can still ride when it's raining or cloudy, one of my few other passions I can't currently afford on disability pension.
I've made up my mind, I just need to win Lotto!
Had I not disturbed this thing I could have bolted my gear to it but I dug a trench for electrical to a garden shed. Guess where it was?
Around 3 feet from my destination at the far end of a trench already dug over a period of several days,
RIGHT in the middle of my path.......
Had I just dug 12 inches to the left or right of it.....
It's over 24 inches width on the large side.