What to stand a mount on (in the garden)

[SimM]

I want to put my steel tube tripod on something more permanent in the garden.

I'm not sure of the mechanics for what makes for a more solid base than a 6" thick block of concrete with a diameter (if round) or square cast in my back garden. Not so big that I constantly step on it and firmer than a patio?

Do I need to lay it (cast it) on bed of sand or gravel or use a membrane?

Thanks

Simon

[SimM]

Has anyone tried a mount like Stacey's pier (Astrostace YouTube): https://www.youtube.com/watch?v=Pg7QlsOlNEI

Her introduction to piers: "So, does anyone else have a pier that has an inbuilt coffee/beer holder and a built in guard system? ".

I do wonder if the blocks are more rigid than a steel tripod - if it's on a firm (concrete) pad?

I could produce a hardwood pier adapter as an alternative to getting a steel/aluminium one - benefits?

Simon

[Dr_Ju_ju]

For Star Parties etc. I take some off cuts of decking board, cut into squares & drill a central indent for the tripod spikes...  

[AdeKing]

Although I don't have one myself, there are plenty of users on here that do.

Affectionately known on here as a Todmorden Pier. 

I think that Peter Drew came up with the idea and has several of them up at the Astronomy Centre in Todmorden.

A search for Todmorden Pier should provide plenty of user experiences.

[spillage]

Depends on what mount you have. You can always use a car brake disc as an adapter. The todmorden will be quick and easier to build but need to be a permanent structure but I guess this is the point of building a pier. I used 8" plastic pipe, sunk two feet into a concrete base with about four feet above ground. This then got filled with concrete.

[SimM]

Todmorden Pier was the name I was trying to remember. I bought two of the concrete hollow blocks and can construct the upper portion.

That's when it starts to be uncertain e.g. jut how much concrete is required to ensure it's stable (I'm mostly on a sandy soil).

I can see that a pier provides a repeatable process e.g. helps with PA etc. but I also wanted to know how much of an improvement it is e.g. is a steel mount an issue that the blocks fix? Is having a steel brake disk any better than wood? What properties are important etc. ?

I'm reading a book on AP that shows a metal spike/bar, driven into the ground, with a nylon plate (to locate it) and an Allen bolt (for the spike to stand on). Seems a good idea, but I wonder if the spike is stable enough e.g. I know that only a slight change in position introduces a change in alignment?

One thing I noticed with using the pavers (round concrete) is that after only a few weeks, they bed down and start to be part of the lawn and no longer rock. I'm tempted to glue 3 washers to help with repeating polar alignment and see how that goes but my feeling is that a slab of concrete is the way to go. Just because it's simple doesn't mean I need to get it right e.g. to improve what I have.

Al least I understand the drinks holder concept.

Simon

[spillage]

Most people say 1m3 but I only went about 700mm3 it depends on your ground. If you use wood it will warp so you want something that is not prone to movement, steel or aluminium.

Are you going to leave your mount outside?

I would say permanent power and connections to the mount will really help.

If you do it do it right or at least do the best you can. You really do not want to have to redo it.

You cannot beat a pier as you can be up and running in minutes (cooling the camera is the longest part). It helps you grab the chance to image at times you would not if you have to set up from scratch.

[SimM]

21 hours ago, spillage said:

Most people say 1m3 but I only went about 700mm3 it depends on your ground.

Are you going to leave your mount outside?

I would say permanent power and connections to the mount will really help.

1m3 or 0.7m3 is a lot of concrete to buy/mix up by hand is a lot! A pulsar dome has a suggested base with a block of concrete 1m x 1m x 0.7m with a separate 150mm deep base for the dome around (but separate) from the pier. That's about 2m3 - enough to consider having concrete mixed and delivered (about £250).

I don't think I would risk leaving a mount permanently outside.

Screwfix have a British General (BG) double socket for outside (with/without RCD) for £30/£10. I have one on an outside double BG socket on a wall overlooking  my patio. It looks very neat and has clips to close and seal over the sockets and also for the plug cables. There is space to add a lock if required. I was considering using one (with the sockets removed and replaced with a cover plate) to make a waterproof access point (junction box) on the side of a future pier.

I was also considering a 100-150mm thick slab of concrete of about 1.2m diameter (TBD) to stand my tripod (0.85m leg-leg) - as an alternative to 3 x 45cm pavers currently setup in a "trial" location on the lawn.

Simon

[JamesF]

The bases for my "Todmorden" piers are about 600mm cubes, perhaps a touch less.  I dropped large stones and suchlike in when I made them to reduce the amount of concrete required.  The piers are not moving anywhere in a hurry.  The bases are standing on rock though.

James

[SimM]

18 hours ago, JamesF said:

The bases for my "Todmorden" piers are about 600mm cubes, perhaps a touch less.  I dropped large stones and suchlike in when I made them to reduce the amount of concrete required.  The piers are not moving anywhere in a hurry.  The bases are standing on rock though.

James

Thanks for the info James, 600 cubed is about 0.22m3 or about 425kg. Can that be right?

How many bags of mix did you use? Postcrete or ready to make concrete (about 16ish)?

Slightly different, I thought about using a similar volume to make a concrete base the area of my tripod x 200mm to stand on a base of sand.

Obviously not permanent as a pier, but a good/bad idea?

Simon

[spillage]

You can reduce the amount needed. If you can get your hands on a auger (I used a 8" auger) and dig in each corner of the hole and  in the middle for the pipe/ mount support. This effectively casts a concrete table in the ground. You might be able to have the main slab only 500mm thick.

[JamesF]

39 minutes ago, SimM said:

Thanks for the info James, 600 cubed is about 0.22m3 or about 425kg. Can that be right?

How many bags of mix did you use? Postcrete or ready to make concrete (about 16ish)?

Slightly different, I thought about using a similar volume to make a concrete base the area of my tripod x 200mm to stand on a base of sand.

Obviously not permanent as a pier, but a good/bad idea?

That's the right kind of ballpark.  They might be nearer 550mm cubes perhaps, but it's in the right general area.  I will have some more accurate measurements somewhere, but I can't find them right now.  Some photos of my build:

(Just noticed the first couple were taken two years ago this week

I bought a dumpy bag of mixed stone and sand (and already had some lying about from another project), so I don't know exactly how much I used in the end I'm afraid.  It also had to do the supports for the framing around the outside of the floor.

I'd probably be reluctant to put anything on a bed of sand, to be honest.  Far too easily rinsed away by groundwater.  Some decent size stone packed well down might do the job though.

James