Garden Pier :-)

[JemC]

Garden Pier :-)

Hi all,
i got the go ahead today to install a pier in the garden,so basically i'm after some info/advice, please bear with me as i am not technically brilliant :-)

i am limited to it's position unfortunately, this is partly due to the garden not being to big and the night sky views available,

i have LP but not a lot i can do about that other than just get on with it,

So my intensions are to have a pier that stands 3ft out of the ground as this height is the current height that i have my EQ5 and am happy with,

Any way before permission was withdrawn or minds where changed i have made a start on the area i am going to place the pier, luckily it is right outside my shed door,

If anyone can give advice/info good or bad on the following it would be very much appreciated,

at the moment i have dug a hole that is currently 2ft deep, i hit clay at 9 inch deep and am still in clay at 2ft? is this good or bad ?

How much deeper should i dig ?

What should the overall length of the pier be to give me the 3ft above ground ( i was looking at 5ft length)

What would be the best diameter of the pier to be ok for my 200p?

and i am sure there will be other questions along the way

Regards

[RichM63]

Clay is what your house was built on.

For an idea as to what it could look like check out this thread that has just appeared.

DIY Pier

One thing, ensure that your hole has straight vertical sides, important for any foundations.

Don't forget to factor in the thickness of your walk way material above ground when deciding on your final pier height.

[damnut]

Hi Jem,

Congrats on getting the  green light. There are a few threads on SGL where folk have documented their pier build. I have a 'portable pier' so have not committed to breaking ground!! If you do a search you will find them, also in obsy builds as the pier is usually the first stage.

If you put some decking around the pier it isolates more vibration too... Found this one but there are lots http://stargazerslounge.com/topic/234625-mikes-roll-away-shed-observatory/?hl=+pier%20+build

Good Luck

[JemC]

RichM63

thanks for that link, just what im looking for

Damnut

nice touch with the decking, had not given that a thought thanks

[ollypenrice]

In designing a permanent pier one thing to consider is that, contrary to popular belief, the top does not have to be level. It is better to have a really stiff top. You'll do a drfit alignment anyway with a permanent setup so go for a really stiff top, not an adjustable one.

Olly

[JemC]

In designing a permanent pier one thing to consider is that, contrary to popular belief, the top does not have to be level. It is better to have a really stiff top. You'll do a drfit alignment anyway with a permanent setup so go for a really stiff top, not an adjustable one.

Olly

Hi Olly

thanks for that advice,

lookiing through the threads virtually all the pier designs i have seen are the ones that are adjustable, not really seen any other designs, any chance you could point me in the right direction where i can find some stiff top ones

Regards

JemC

[laser_jock99]

Hi Olly

 

thanks for that advice,

lookiing through the threads virtually all the pier designs i have seen are the ones that are adjustable, not really seen any other designs, any chance you could point me in the right direction where i can find some stiff top ones

 

Regards

JemC

No real need for any adjusment on a permanent mount- just build it so it's level in the first place and that will be good enough.

 

My design of mount features a machined steel puck which drops into the steel pier tube.

 

The main mount 'tripod' bolt is accessed via the 'owl hole' in the steel tube.

There are of course many other ways of securely mounting the head on the pier tube - but it does make me chuckle when people go to the trouble of pouring a tonne of concrete into the ground, make a super stable pier and then attach the important bit on a few wobbly bits of M10 studding!! The most laughable part is that 'leveling adjustment' is not needed anyway.

[JemC]

Hi Laser_jock99

That looks a pretty neat design,

i take it the hole near the top is so you can access the nut for tighening

[laser_jock99]

Hi Laser_jock99

 

That looks a pretty neat design,

i take it the hole near the top is so you can access the nut for tighening

The hole is for access to the nut and also serves to run the all the cabling down the tube.

[ollypenrice]

The top plates that you often see standing on three lengths of threaded bar just don't need to be on the threaded bar. As long as the pier has a cutout so you can get your hand underneath to fasten the mount on, that's all you need. 

Mercifully more and more manufacturers are moving away from designs which are held on from below. The sooner this practice disappears altogether the happier we'll all be, because it complicates pier design no end.

Olly

[Owmuchonomy]

I agree with the above actually and my pier has an adjustable top albeit on 16mm bar!  If you can, go for a design that is solid rather than adjustable.  Easy drift align methods in PHD2 guiding software mean that PA is a doddle these days.  Play around with your set up now and make sure your calculated standing height is acceptable for most views if you are going to use it for observing.  I added an extra 160mm of height to my concrete plinth design at the last minute based on a lot or playing around with my scope set up.

[JemC]

Well thats the hole dug out, finally settled on 2ft square x 2ft deep, wouldn't like to be doing that all day

also done quite a bit of messing around with the EQ5 trying different height settings, come to the conclusion that somewhere around 4ft-6in tube length give or take is going to be sufficient,

quite like the design that Laser_jock99 has on his set up, just need to find somewhere that can make that for me, few phone calls needed i think!

[frugal]

If you are not using a levelling plate, then how do you ensure that the top is perfectly flat and level?

[RichM63]

Build it right in the first place and it will be, but it does not have to be if using guiding equipment and software, which is likely with a permanent pier.

Even certain expensive mounts do not posess a leveling method.

I'm hoping that EDF will cut the concrete pylon level but if not will trim with the diamond disc. Like others I'm looking into how to attach a mount to an existing reinforced concrete base.

[NEM]

It doesn't have to be level as long as you can adjust the polar axis of the mount to point to the north celestial pole.

[frugal]

Then why is step 1 in every set of setup instructions always "ensure your tripod/pier is level"?

To use a flight analogy, Az and Alt adjustment bolts will counter pitch and yaw, but not roll.

[Gina]

Roll is covered by slewing and guiding.

[frugal]

Gina, 

I was under the impression that using guiding to counter roll would lead to field rotation and elongated stars at the edges of the frame?

[Gina]

Not it you get the polar alignment right with an equitorial mount.

[frugal]

Well, you learn something new every day. I had always assumed that you needed the base to be perfectly level

[Gina]

Well, you learn something new every day. I had always assumed that you needed the base to be perfectly level

Yes, I was of that opinion when I built my pier but have since learned that it's not so.

[NEM]

Having the base level makes polar alignment easier, but it's not essential. If it's not level then when you change the azimuth setting the altitude changes as well and vice versa. So you have to make repeated changes to both until you get it set. It takes longer to set, but if you're using a pier you only have to do it once.

Noel

[JemC]

Well i'm off to see a friend tomorrow regarding the pier design, hopefully he will be able to construct something along Laser_jock99 design,

as i said earlier i'm not technically gifted when it comes to things like this, so i am grateful to the likes of Olly, Laser_jock99 and Gina for sharing the knowledge they have with regards pier design/set up, i also appreciate the input from other members as well, it all goes towards my learning

i suppose i better try and work out how much concrete i am going to need to fill this hole i dug

will update tomorrow if he can do it,

Regards

[laser_jock99]

If you are not using a levelling plate, then how do you ensure that the top is perfectly flat and level?

I used a spirit level when I built both my piers. That way I knew they would always be level and not need further adjustment.

There was a certain amount of adjustment possible in the M18 bolts fixing the pier to the concrete mass- but it was close enough not to be needed.

[JemC]

Well the pier is under construction  

It is however going to be a slightly different design to the one i had in mind, but still capable of doing the job (he said with fingers crossed)

all being well it should be ready for me to collect tomorrow, will upload some pics when i get it home,

Regards