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Which pier to get?

peroni

By peroni
in Discussions - Mounts

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peroni

peroni

Posted
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Hi All

I've chewed over quite a few options for a pier to add to my obsy and image from. I've discounted making one and decided to go down the more expensive but easier route of purchase and bolt down onto a large block of concrete. My dilemma is which pier to get.

Currently I have an HEQ5 mount and ED80 scope with CCD. I have no plans to change this kit but would like to keep my options open and possibly upgrade to EQ6 in the future.

These are the piers I'm looking at:

Rigel Pier for HEQ5 - £420 - 1125mm high

http://www.pulsar-optical.co.uk/prod/pier/eq5/piers.html

AC282 Standard Pier for HEQ5 - £472 - 1010mm high

http://www.astro-engineering.com/prod/astroengineering/telescopemountings/stdpiereq5.html

It looks to me like the AC282 is a more sturdy design but the Rigel pier has that little bit of extra height which is preferable. 

I currently have my tripod set at maximum height 1150mm

Does anyone know the diameters of the Rigel pier at it's base and the diameter/thickness of the tube?

My preference based on looks is the AC282

My sensible head says get the Rigel one as it's a bit higher

What are peoples experiences with one or both of these?

Jump in a play devil's advocate if you like. Suggest another maybe.

I'd need to keep the concrete base level with the patio so the shed sits on top. I have a Keter shed/obsy with a plastic floor.

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spaceboy

spaceboy

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I'd probably go with http://www.astro-engineering.com/prod/astroengineering/telescopemountings/stdpiereq5.html out of the 2. The mount adapter is solidly fixed to a flat surface so no way of there ever being any chance of play introducing itself in to the mix.

Saying that though at £400+ a pop I would get in touch with them and ask for plenty of pictures and if possible a video. S'N'S love posting youtube vids so I'm sure they would be more than happy to accommodate ;)

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peroni

peroni

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I'd probably go with http://www.astro-engineering.com/prod/astroengineering/telescopemountings/stdpiereq5.html out of the 2. The mount adapter is solidly fixed to a flat surface so no way of there ever being any chance of play introducing itself in to the mix.

Saying that though at £400+ a pop I would get in touch with them and ask for plenty of pictures and if possible a video. S'N'S love posting youtube vids so I'm sure they would be more than happy to accommodate ;)

I've found this vid the tube 

I'll give some serious thought to the height of this pier

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Zakalwe

Zakalwe

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I've found this vid the tube 

I'll give some serious thought to the height of this pier

There's copious quantities of snake oil in that video and much of it is nothing more than pseudo-engineering. Talk of he welds "pre-stressing" the steel is laughable.

It'd be worth looking at Home Observatories as well. They make piers too. Or get in touch with a local steel fabricator. They might do a one-off job, which might turn out very cheap.

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mikeDnight

mikeDnight

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Don't discount having a pier made. I had a pier made for my observatory and it cost £30. That's a heck of a lot cheaper than the options you're looking at. I had a local sheet metal worker construct a pier with a steel end plate drilled to take the mounts fixing bolt, and with an access hole cut in the side. It was 6' 6" tall, I then painted it with red lead before sinking it into am hole in the ground 18" deep and embedding with rapid setting postcrete from B&Q. I then painted it with hammerite and it looks beautiful. The observatory floor surrounds it and there are no feet to trip over. Over all, it probably cost me no more than £60 around three years ago and about three hours of my time.

You could always check out local scrap yards for steel tubing or buy tube cut to length. My pier is of square construction and was made to order saving me having to run round finding scrap metal that would probably have cost just as much.

With the money you save you can buy another eyepiece or two! Food for thought!

Mike :-)

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trazor

trazor

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Hi All

Does anyone know the diameters of the Rigel pier at it's base and the diameter/thickness of the tube?

I had this pier installed about  6 months ago.

The base  is approx. 450mm dia  x 12mm thick.

The webs are 8 mm thick.

The tube is  168mm dia  x  5mm thick.

Please note.......The height of my pier is 1080mm with the adaptor fitted, something you would need to check.

The pier is rock solid and holds my EQ8 without any problem at all, I am very pleased with it.

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trazor

trazor

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There's copious quantities of snake oil in that video and much of it is nothing more than pseudo-engineering. Talk of he welds "pre-stressing" the steel is laughable.

I agree, much of the video is sales spiel, and has no factual basis.

However  the welds do stress the steel.

As the molten weld cools it contracts and introduces stress, but this is not a desired quality.

http://www.thefabricator.com/article/testingmeasuring/how-to-relieve-stress-in-welding

High quality fabrications are stress relieved at up to 650 deg C, which removes all stress 

This would be ideal for a pier but expensive at about £150.00 pounds.

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Zakalwe

Zakalwe

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I agree, much of the video is sales spiel, and has no factual basis.

However  the welds do stress the steel.

As the molten weld cools it contracts and introduces stress, but this is not a desired quality.

http://www.thefabricator.com/article/testingmeasuring/how-to-relieve-stress-in-welding

High quality fabrications are stress relieved at up to 650 deg C, which removes all stress 

This would be ideal for a pier but expensive at about £150.00 pounds.

Yes, I know that. But to try and imply that it has anything to do with making a pier better is rubbish (as Mr Dalby implies). I think that he is trying to make a connection with pre-stressed concrete (concrete=strong, pre-stressed concrete=even stronger, "pre-stressed steel *must* be better than ordinary steel) :rolleyes:

I spent 10 years working in various steel fabrication works- welding ally and steel. I'm far from an expert, but I can spot when someone is talking through a part of his body that isn't normally talked through....

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Tinker1947

Tinker1947

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They pre-stressed the rails in use on the High Speed line from the channel tunnel to London, the method used, they simple put a large electric heater on the end of rail then the rail expanded for several hundred yards, the heater then got moved along untill the whole length had been expanded, the rail had no joins between various locations one length run from the Lenham Loop to the North Downs Tunnel, distance roughly 10 miles(that's one length of rail) , they said the rail could endure tempretures + or - what ever the British weather could throw at them.......How this would translate to a Astro Pier i'm not sure...I only read the section of this thread previous to my input, sorry if its not linked.......

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Zakalwe

Zakalwe

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.How this would translate to a Astro Pier i'm not sure...

It wouldn't. Completely different application and requirements. And the rails are welded, normally using a thermite welding process

They also pre-stress the rebar in concrete assemblies, as concrete is good in compression and poor in tension, whereas steel is poor in compression and good in tension. Also nothing to do with holding a mount and OTA a metre and a half off the ground.

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1parsec

1parsec

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Yes, some weird terminology used in that video.

The most important feature on a surface mounted pier is to correctly fillet the base plate to the sides of the tube. Use 6 or 8 smaller pieces rather than 4 tall ones.

Braces 200 mm tall will be more than adequate. If you need tall braces then the tube diameter choosen is too small ! 

Drill the holes through the base plate close to, and with in the radius of the braces - this makes a big difference in the final pier rigidity.

The base plate doesn't need to be large in area , just wide enough to fit the braces.

( Next time on the motorway, look at the overhanging information signs. The tube is a large diameter and the base plate is just a bit larger than the tube with lots of small braces.)

One thing I do agree with in the video is the use of studding to separate the top plate. Some 30mm or 40mm diameter solid spacers kept as short as possible would be more suitable, as levelling adjustment is definitely not needed for an EQ mount.

Dave.

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peroni

peroni

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@Everyone

Thanks for all your input so far. Just when I thought I was close to a decision: the old 'speak to a local fabricator' option is back in the mix.

Keep the comments coming, I'll let you know when I finally decide.

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ollypenrice

ollypenrice

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If prettiness isn't a priority you could buy a cheap MIG welder, angle grinder and the steel for less than the asking price of these piers. Then you could spend the next twelve years using it to make other astro items. (3 x steel framed roll off sentry box observatory chassis, 1x large rolling roof, 1 x adjustable observing chair, 2 x more piers, long lengths of safety railings round observing sites... and then the non astro stuff like a permanent sun pergola, several garden tables, several benches, shelving units for the workshop etc etc.) In the end it proved to be a very cheap bit of kit! And if I can learn to make a joint in twenty minutes (pre internet and you tube) then so can anyone, I really do promise you!  :grin:

ROLLING%203-S.jpg

foundations1-S.jpg

1-S.jpg

Olly

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Earl

Earl

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The rats nest is quiet an interesting debate, as is the idea of needing to level your mount... thats what your alt az adujsutments do to the mount. by aligning the Polar Axis. Flat is ok but there is no need to go for adjustable, the advantage with this style of pier is the ease of attaching a pier adapter for your mount.

The heavier the better, if casting a concrete pier enough depth to maintain good stability, there must be a ratio for above ground vs below im unaware of it, but your not going to be casting a AAA emplacment like some people do.

I have been getting 20min subs on a tripod all be it a sturdy one, Im switching to an offical AP pier for my AP900 soon and expect ill have no problems,

Free standing works fine, look at the results Olly gets on Yves setup free standing.

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ollypenrice

ollypenrice

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Posted

The rats nest is quiet an interesting debate, as is the idea of needing to level your mount... thats what your alt az adujsutments do to the mount. by aligning the Polar Axis. Flat is ok but there is no need to go for adjustable, the advantage with this style of pier is the ease of attaching a pier adapter for your mount.

The heavier the better, if casting a concrete pier enough depth to maintain good stability, there must be a ratio for above ground vs below im unaware of it, but your not going to be casting a AAA emplacment like some people do.

I have been getting 20min subs on a tripod all be it a sturdy one, Im switching to an offical AP pier for my AP900 soon and expect ill have no problems,

Free standing works fine, look at the results Olly gets on Yves setup free standing.

Since buying Yves free standing pier/mount I've made simple attachments screwed to the floor to stop it being nudged but, yes, used with a 14 inch scope and 2.4 metre focal length it did 30 minute subs free standing. This mount has, in over three years, never lost a sub to guiding error.

I do think there's a lot of internet 'white noise' out there regarding piers! There isn't much to them.

Olly

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peroni

peroni

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If prettiness isn't a priority you could buy a cheap MIG welder, angle grinder and the steel for less than the asking price of these piers. Then you could spend the next twelve years using it to make other astro items. (3 x steel framed roll off sentry box observatory chassis, 1x large rolling roof, 1 x adjustable observing chair, 2 x more piers, long lengths of safety railings round observing sites... and then the non astro stuff like a permanent sun pergola, several garden tables, several benches, shelving units for the workshop etc etc.) In the end it proved to be a very cheap bit of kit! And if I can learn to make a joint in twenty minutes (pre internet and you tube) then so can anyone, I really do promise you!  :grin:

This is another good suggestion. I hadn't considered making a metal pier but I do have an angle grinder already. I'll look into this.

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