RogerTheDodger

Gerry, what scope and mount are you using?

The main reason people end up with a rat box is to loosen the nut underneath so they can rotate the mount for PA on the cheaper mounts.

I will agree that the height of those bolts was ridiculous and unnecessary though

Considering I actually lift the mount and it's plate off after every session (it sits in the edge of a shrubbery, so I have to bring it in for weather protection) I thought my problems were due to my pier compromise, but most of it was poor PA, even though I thought it was good, general backlash in the mount and PE. Having said that, I don't always get 30 min subs, but I'd take any bet that says it's my peir to blame.

Wow... rotational shear... flapping 10mm plate... I bet if I showed him my brick pier sitting on a concrete paving slab on sand/gravel that gets 30 min subs his head would explode

Finished the first one... I got teh pulleys from Motionco, they have a very useful util to choose the centre distances and belt length http://www.motionco.co.uk/cd_calc.php?submitted=2&tooth_type=2.032&pulley_one=10&pulley_two=48&length=80

Here's my latest pier, with a couple of pheasants. The brick part was salvaged from my old one with a new base - concrete paving slab on gravel/sand underlay.

Yes, the ascom sim works ok.

As I don't leave the mount out the top nuts are just finger tight. If you are building it inside an obsy then I'd use concrete instead of mortar for the top as you say... I tend to use two spanners in opposite directions if I am tightening nuts anyway.

Hi Dave, I had to do the registration to get your tool to see it, but Neb throws the error. No biggie, I can just use your controls.

Got the electronics for the first one assembled and working with the test program, but trying to connect to it from Nebulosity throws this error when I select Properties... any ideas?

No rebar needed. You only put rebar into concrete because concrete is flexible, and the rebar is to stop it flexing tto far and cracking, and if it does crack to limit the catastrophic failure... really not needed in something of this size. The top is actually standard mortar, I just built some wooden shuttering, sealed it around the top with bathroom sealant, poured in some mortar and then pressed the bolts in (the bolts were in the top disc so they were aligned). The disc is laser cut/drilled aluminium, I got a guy in Scotland to cut them for me. It's also not on a concrete block at the bottom, it's just a (very stable) paving slab... just keep it simple If you live in a heavy frost area then you would need better footing than a slab so frost doesn't move it, but this has worked down to -10 c so far without moving.

IMO people over complicate things, if your system is balanced then the only forces are compression, downwards through the pier, and none of our systems are heavy enough to even be noticed by the mortar. There are no torsion forces to worry about, and with any pier, you don't walk near it when an imaging run is on. Just remember that people happily carry a HEQ into a field and set it up on a tripod to do imaging without worrying that the legs are flexible (way more than concrete or brick/mortar) and resonate beautifully when vibrated I'm on my second brick pier, and it won't be my last

Yay the bits have arrived! (mostly) so I can start work. I bought the Nanos and the motors direct from China, £10 total for two of each.

After moving house last November, I have built another one and I'm still happy with the design - I haven't hit the pier yet with the scope