DIY Pier Height?

[RichM63]

Hi folks, I think that I may have just struck lucky.

On my land I have 2 reinforced concrete electricity poles. Each 50 - 60 ft high.

There is a project afoot to remove these and replace them on the lane side. ie no longer in the garden and remove all the medium tension lines.

One of the posts is perfectly situated for uninterrupted views of most of the sky with a bit missing to the NW.

These posts are set in about a depth of 2m of poured concrete.

The plan was to remove them completely.

However the EDF project manager has just visited to finalize the new post positions etc, and during this conversation I asked him (tongue in cheek) if rather than remove the one at the perfect future obsy spot whether it would be possible to cut it down to a height specified by me and leave it undisturbed as a deep set reinforced stump for use as a future telescope pier.

Showed him the scopes and a few pics of the DIY Obsy's on the forum so that he could understand more fully.

Instantly he saw the point and agreed that they would cut it down to size rather than ripping it out.

My question is, what height above ground should I specify?

I need to get this right as I doubt that I can ask EDF to pay for my pier installation a second time.

I am about 5' 10" and would be installing a flagged surround around the post. (later).

I doubt that I could produce a more solid DIY pier even if I tried.

My Avatar pic was taken with my back to this post.

Thanks for any info'.

Cheers,

Rich

[nmoushon]

Well it all depends on how you build your obsy. If time is of the essence then I would say have him cut it taller than you think you would need it. You can always rent a concrete saw and cut it down to size later or build the obsy a little taller to match the pier.

[RichM63]

I agree nm, I'm just looking for a ball park figure at this time because I need to paint mark the post in advance.

It may well be another 6 months to a year before the guys cut it down but I know what will happen if I don't mark it up.

Regards trimming, a diamond disc stone saw is no problem.

Then the plan would be to deep drill into the exposed end and set bonded bolts to afix the mount base plate.

[pete_l]

Have a look at the specifications for things like an EQ6. These have adjustable legs that range IIRC from about 95cm to 120-ish. Add on to that about 30cm for the mount from its base to the point of attachment of the scope. The ideal height will depend on whether you intend to use a refractor or a reflector for viewing. If it's for imaging, it probably doesn't matter - so long as you can lift the mount and OTA (separately) to the required height.

As nmoushon says: better too tall than too short as it's easier to build up the ground around the post than to re-cut a reinforced concrete pole.

Alternative idea: why not leave the pole at its existing height and buy a ladder? I bet the views from the top are even better.

[RichM63]

LOL Pete, it would take more than my ladder to get me to the top of the existing post! Currently a buzzard snoozes there.

Good point about refractor/reflector though.

I have been looking at commercial piers (as per ^) they seem to range from 350mm min to 1327mm max so I'm thinking an initial cut of 1500mm to either allow for a raised walk around platform or a re-cut if required.

[nmoushon]

I think that would be a good idea. Would allow for the most options in the future once you have everything decided.

[Mickthedigger]

I have a little bit of data for you. The NEQ6 mount is 73.5cm high with the legs retracted. And 124cm high with the legs fully extended. The tallest measurement *might* be ok for observing. If you are looking straight up with a really long refractor. But I would not make it that high for astrophotography. Personally I would make a pier closer to the shorter hight. I hope that helps. If you would like anymore info just ask and I'll see what I can do for you.

[mhard26339]

When I was using my NEQ6 on its tripod I set it up to 40CM on the plate, when I made my pier for my Obsy I made it 39CM hight to the mounting plaorks fine but I am only 5'-6" tall!!

As always your call

Regards

Mike

[NickK]

I'm considering a garden pier at 36" from the floor to the base of the NEQ6.

[Mukv]

Greetings

Set up your scope on the mount as close to the intended location within the confines of the walls of the obsy and point it at the lowest horizon you should be able to extrapolate pier to wall height from this data using a tapemeasure. Mocking up the height of the walls using a pole of some type will help with setting a floor level or datum to work from.

any pictures?

Andy