Benefits of a pier

nobbygon (Angus) · #1 28-09-2012, 03:20 PM

Hi,
I'm currently doing the ground research on building a small backyard observatory. Due to the fact that I'm living in rental accommodation and moving with work constantly (every 3-4 yrs), I've decided to go with a small roll away shed to cover the mount/scope.

My question is, what is the benefit of digging a big hole, filling it with concrete and putting a concrete pier in it? I understand that it will be quite stable and free from any vibration from the ground but does it really offer much over putting a decent footing down and placing a tripod there instead?

I use an NEQ6 and it seems like it would be more hassle than worth building a concrete pier when I have a decent tripod.

Thanks,
Gus.

Kunama · #2 28-09-2012, 04:33 PM

I guess the biggest benefit is being able to align the mount to SCP as once you have the pier set, levelled and true south marked you will save time rather than aligning your tripod each time.

I don't think I would bother with a pier on rented properties unless I had a loooooong lease!

GrampianStars (Rob) · #3 28-09-2012, 05:17 PM

Quote:

Originally Posted by nobbygon

Hi,
I'm currently doing the ground research on building a small backyard observatory. Due to the fact that I'm living in rental accommodation and moving with work constantly (every 3-4 yrs), I've decided to go with a small roll away shed to cover the mount/scope.

My question is, what is the benefit of digging a big hole, filling it with concrete and putting a concrete pier in it? I understand that it will be quite stable and free from any vibration from the ground but does it really offer much over putting a decent footing down and placing a tripod there instead?
........

Years ago I was in a similar position
I just used a 6' x 300mm dia. treated post
drilled and installed threaded rod on top
burried 3' in the ground.
"Shovel about 3-4 inches of dirt around the bottom of the hole and tamp that dirt around the post you should not have to tamp it very hard since there are only a few inches of dirt to tamp. Level the post. add 3-4 inches more dirt, tamp it, and level the post again. Continue until the hole around the post is filled to the ground level of the post"

I was vibration free

and removable

multiweb (Marc) · #4 28-09-2012, 06:02 PM

The main benefit is that you don't have to polar align everytime so it does save you a lot of time setting up.

leon · #5 28-09-2012, 06:16 PM

Like that idea Rob, what a good idea and cheap mate.

Leon

mswhin63 (Malcolm) · #6 29-09-2012, 10:21 AM

Rob, I like the idea, I will investigate too, although would still need to check with the landlord as inspections wouldn't go down well with a post sticking out of the ground.

nobbygon (Angus) · #7 29-09-2012, 11:11 AM

If you set the tripod up and polar aligned it and didn’t move it again, (e.g. just rolled the shed back over the top without touching anything) wouldn't that serve the same purpose as a pier? Why would a tripod not stay polar aligned if you didn't move it?

Kunama · #8 29-09-2012, 11:18 AM

Quote:

Originally Posted by nobbygon

If you set the tripod up and polar aligned it and didn’t move it again, (e.g. just rolled the shed back over the top without touching anything) wouldn't that serve the same purpose as a pier? Why would a tripod not stay polar aligned if you didn't move it?

Nothing wrong with this idea, a friend had 3 eye-bolts placed on the concrete slab next to 3 small holes drilled into the slab. The tripod leg points went into the holes and small turnbuckles then tensioned the tripod down, very solid !

RickS (Rick) · #9 29-09-2012, 02:42 PM

The main advantage of a pier over a tripod is that it doesn't have legs for your scope to run into...

2stroke (Jay) · #10 30-09-2012, 04:10 AM

Quote:

Originally Posted by RickS

The main advantage of a pier over a tripod is that it doesn't have legs for your scope to run into...

+1 saves you tripping over tripod legs and whacking out alignment. Nothings worse when your done alot of time drift aligning to only lose it all in a split second. There more stable, have less vibration and on top of that setup time is quick due to having a mark on where you locked it down from last session. I wouldn't bother with a portable pier but fixed has some worth while pay offs even if it not a perm ob. I want to make up 2 now for the heq5 one in the rear of the backyard and one upfront

Logieberra (Logan) · #11 30-09-2012, 09:39 PM

In your situation, renting, a pier is a no go.

Tripods that come with the better mounts, EQ6 size and above, are perfectly adequate. Save your money, and get your bond back!

ZeroID (Brent) · #12 01-10-2012, 08:44 AM

Tripod, three wee paint spots on a suitable hardened surface ( mine was the driveway ). Worked for me.

el_draco (Rom) · #13 02-10-2012, 02:42 PM

I have no choice but tot to go for a pier as my new setup will be to heavy to move. I reckon I'll go steel filled with expansion foam to deaden vibration but am concerned about the thermal mass.

I'm looking at around 120kg of steel in the sucker I'm contemplating. Can anyone point me at some info where I can determine whether this is going to cause issues?

Rom

Logieberra (Logan) · #14 02-10-2012, 05:17 PM

Save the foam for your bath, pointless IMHO....

el_draco (Rom) · #15 02-10-2012, 07:23 PM

Quote:

Originally Posted by Logieberra

Save the foam for your bath, pointless IMHO....

I've actually used this stuff before on a another scope. It turned a "ringing bell" into a dull thud. More concerned about the mass of metal, but just found a partial solution that will halve the mass requiresd. Still like to see any hard data on this issue.

Logieberra (Logan) · #16 02-10-2012, 07:26 PM

Sounds like a bandaid, for a pier that is insufficient from the start. Back to the drawing board perhaps

DJT (David) · #17 12-10-2012, 10:09 PM

Just did my first test shots with a permanent pier in new obsy having previously had a tripod permanently left outside, albeit embedded in lawn..

No foam, just a good concrete base and strong fixings for the pier along with some time and effort on the initial drift alignment.

Massive grin on face watching flat lines on phd...snort..

If you don't want ringing noises in your pier, don't hit it..dull thud indeed.

frolinmod · #18 13-10-2012, 04:23 AM

All tripods, even the best of them, move an annoying amount over time. You end up having to re-polar align every so often.

If you can't install a permanent pier, then a 10" diameter Astro-Physics portable pier on a level or near level surface works better than a tripod.

el_draco (Rom) · #19 13-10-2012, 07:11 AM

Quote:

Originally Posted by DJT

Just did my first test shots with a permanent pier in new obsy having previously had a tripod permanently left outside, albeit embedded in lawn..

No foam, just a good concrete base and strong fixings for the pier along with some time and effort on the initial drift alignment.

Massive grin on face watching flat lines on phd...snort..

If you don't want ringing noises in your pier, don't hit it..dull thud indeed.

Obviously whacking a pier is not a goal in itself, but it does identify the resonance issue inherent in steel tube piers, or hollow section aluminium truss components. Add expansion foam and the resonance is effectively eliminated.

TechnoViking (James) · #20 06-11-2012, 12:03 AM

i collected sand from my local river bed which seemed to absorb almost all vibration in my pier, I got the idea from a stablizer that i use for Archery which is filled with a very fine sand. Works a treat! also the other bonus is that when its time to move, just unbolt the pier, tip the sand out which will make your peir alot lighter to move