Mystery Pier - advice please...

[IanH]

Hi Everyone,

Thanks to a previous owner of my house I have a strange pier/pole in my garden which might be 20-30 yrs old or more, is very solid, and has always been believed to be a rather over-engineered clothes line pole. But, the washing line would be very long and there's no sign of where to attach it at the other end. So, now I'm learning about telescopes, I'm wondering could it instead possibly be a observing pier?!

The pole is about 5 foot 6" tall, extremely sturdy (completely immovable) made of some strange non-rusting alloy and with a fairlylevel flat top. The top is just over 4 inches in diameter, with a central hole about an inch wide and four bolt holes/slots on the perimeter. In terms of location it's at the end the garden, in the right place for viewing the ecliptic and most of the sky apart from the east. It also avoids the light pollution of London. The height is probably right for standing and looking through a long refractor.

I'm attaching a couple of photos - hopefully you can see what I'm trying to describe.

I would love to use this a quick to set up manual Alt-az mount, maybe with a refractor like a Tal 100. But I don't know what mount head I need to get and how to fix it on.

If anyone has any ideas on how to go about it I would be very grateful.

thanks for your help,

Ian

[Bizibilder]

Your pier seems to have welds on it, so it may be steel. Is it magnetic? Just try and put a magnet against it - if it is magnetic then it is possibly galvinised steel (zinc coated). if it really is solid then it would make a good pier for visual work. All you would need to do is make an adapter plate to allow your telescope mount to fit onto your pier. You would need something that reproduced the top of whatever tripod was supplied with your mount. The four "bites" would make ideal places to bolt your adapter onto the pier. It would make complete sense for it to have been used for a refractor in the past.

[The Sailor]

Ian, before you do anything, have you checked how far down the pole goes by putting a weighed line through the hole at the top. It may not be a pier but an air hole for something below, just a thought and maybe safer to check.

Jim

[IanH]

I am glad you both think this might be useable. I will see if it's magnetic and have another look at the hole when the snow has eased off.

I had not thought of an adapter plate - I guess that means I could choose any mount.

Thanks for you rhelp,

Ian

[The Sailor]

Ian, I had an adapter made by a lad on SGL, not a plate but a piece which attached to the pier and then the mount on top with a space between to put the mount bolt. I have used it for both the NEQ6 Pro and the CG-5GT and worked quite well, I will do a search, maybe someone else can help there, I think the cost was about £120.

Jim

[IanH]

That would be great. I am starting to understand the concept now. I'd forgotten that when I put my mount (SW AzEQ6) on it's tripod it's tightened from below - so there's no way that a mount would go on the pier without something in between.

Ian

[Bizibilder]

All you need is a steel plate held bu four sets of bolts with a gap of around 1" between the new plate and the top of the pier - just so you can get the bolt in. Most pier type mounts have this double plate arrangement.

The picture shows my own "top plate" which will take an EQ3 (I think) an EQ5 or an HEQ5. you can just see the lower plate underneath - in your case this would be the pier top plate with the "bites" out of it.

[IanH]

That's very nice. It looks very solid. Do you think something like that could be made from wood, or is the strength of metal essential?

Ian

[The Sailor]

Ian, wood will not be rigid enough, at some point there will be flexing and then you will have trouble at the wrong time. Roger's pier head is nice and solid, mine is round but in the end the same solid platform to take a weight. At some point you may want to upgrade, this means more money attached to the pier, you don't want to scrimp .

Jim

[Bizibilder]

You can probably get some bits of steel from your local "steel fabricator" - these are the folk who make fire escapes and garden gates for posh houses etc! The plate will need drilling but the "round bit with a central hole" (turned on my lathe) could simply be two or three steel blocks suitably arranged to support the base of the mount. If you are lucky (or have access to a lathe) you may find an engineering company who could machine the parts for a few bob. The other possibility would be to find your local model engineering club - maybe a member would oblige?

[IanH]

Ah yes, good point. I wouldn't want to risk anything breaking - that would be a very expensive learning experience.

Is vibration an issue with a pier mounting? - the post itself seems very solid - probably in concrete. Is the adapter plate you use damped, or is it enough for it all to be well tightened down?

Ian

[Bizibilder]

Just tighten everything well. Your pier will vibrate a little more than some shorter / more solid/ greater diameter piers but it should be fine for visual work and planetary photography using a webcam or DSLR type camera. It may not be quite vibration free enough for long exposure deep sky photography - but then again it may work well enough.

[IanH]

That sounds fine then. I will get planning on this. I know a chap who used to restore vintage cars and he had his own workshop - if he can't do metal work I am sure he will know people who can.

In the meantime I'll start saving up for a simple AltAz mount and refractor.

Thanks for all your advice. You have both been very inspirational.

Ian

[The Sailor]

Not a problem Ian, good luck with the build

Jim