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MattGoo's Block Pier


MattGoo

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Background:
Even though I'd really like one, it's not entirely practical or financially viable at the moment for me to have a permanent observatory in my garden.
I therefore thought the next best thing is to build a pier - which should offer superior stability than a tripod and not take up much room.
This idea was run past the wife and surprisingly approved without much fuss. When not in astronomical use it was agreed that the pier will be topped with a sundial in order to make it blend in a bit better.
Since I was looking for a low cost option, I've taken the inspiration for the build from the piers at Todmorden Observatory, which I know a few other SGL members have also implemented.
Materials for pier:
Tools:
  • Pencil
  • Ruler
  • Spirit Level
  • Drill
  • Masonry Drill Bits (5mm, 10mm)
  • Wood Drill bit (10mm)
  • Spanners
  • Spade/Trowel
  • Saw suitable for metal
Construction Instructions:
  • Select a suitable site in your garden
  • Dig a hole approx (30cm x 30cm square) x 40cm deep

Pier Hole

Pier Hole Close Up

  • Cut the M10 threaded bar into 4x 33cm and 4x 10.5cm lengths
  • Bend the M10 threaded bar 33cm lengths at right angles approx 8cm from one end (may need to heat them up to do this)
  • Drill 4 holes into one of the concrete blocks using the 5mm drill bit, then go through again with the 10mm bit
  • Place the other block on top and mark through the holes with a pencil, then drill the second block
  • Use the 4x 10.5cm lengths of M10 threaded bar to attach the two blocks together using washers, nuts and the dome nuts on top
  • Drill 4 holes in the base of one block
  • Put an off cut of wood on the block and mark through the holes with the pencil
  • Drill the holes in the wood
  • Attach the 4x 33cm lengths of M10 threaded bar using nuts. This is only temporary, since this is effectively a 'former' in order to ensure that the bars line up with your block holes when they've been set in the concrete

Former

Former underside

Former Concrete

  • Mix most of the concrete and pour into the hole
  • Insert the 'former' ensuring that the underside nuts are not submerged, that approx 50mm of bar is above the concrete, and most importantly the 'former' is level

Former Concrete

  • Add more concrete if necssary & tamp down to make the top smooth
  • Wait until the concrete is set & remove the wooden 'former'

Concrete Bars

  • Smooth out any unevenness in the concrete, ensure it is approx level and that the block fits onto the exposed threaded bars
  • Add a small amount of concrete & place the block on top, adding more concrete around the sides as necessary
  • Make sure the block is as level as possible
  • Wait until the concrete is set and fix it into position using washers and dome nuts
  • Paint the whole thing
Other notes:
You could use cheaper zinc plated threaded bar and nuts/washers, I selected A2 stainless steel for longevity and anti-rusting.
Stainless steel comes in A2 and A4. A4 is generally more expensive and is mainly for marine use.
Another option for the base is bolting it to some freestanding paving slabs
Another option for attaching the blocks and base together is using specialist glue
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I have a Skywatcher EQ6 mount, so the following is applicable to that. Most other mounts can be attached in a similar way to this type of pier design.
Materials for pier adapter (retail):
Materials for pier adapter (locally sourced):
  • M12 Stainless Steel A2 Threaded Bar (1m)         x1  £ 6.62  Toolstation  http://www.toolstation.com/shop/p37920
  • M12 Fastener                                                       x1  £ 4.50  Ebay           http://www.ebay.co.uk/itm/221225381173
  • EQ6 Adapter plate                                                 x1  £--.--  Society member
  • M10 Stainless Steel Socket Head Bolts (80mm)   x4  £ 3.53  Ebay           http://www.ebay.co.uk/itm/150846401601
  • TOTAL                                                                       £14.65
One engineering member of our society was able to fabricate a EQ6 adapter plate from aluminium for me, taking the measurements/profile from my existing EQ6 tripod head. This was a substansial cost saving over the ones available from the likes of AltairAstro which are approx £80, but meant I needed to purchase the 4x M10 socket head bolts, which are normally included in the retail versions.
Another option is to use a car brake disc.
Tools:
  • Pencil
  • Drill
  • Masonry Drill Bits (5mm, 10mm, 12mm)
  • Spanners
  • Saw suitable for metal
  • Compass
Adapting for EQ6 use:
  • Find the centre of the top of the block
  • Use a compass to find North and mark the direction
  • Place your adapter plate on top, align the peg with North and mark the required holes
  • Drill through with the 5mm drill bit, followed by the 10mm drill bit. (My EQ6 needs a 12mm hole in the centre)
  • Attach the adapter plate using the M10 socket head bolts and washers/nuts
  • Test fit the mount on top
  • Cut down the M12 threaded bar to a suitable length so you can safely secure the mount with the M12 fastener
  • When skies allow polar align & enjoy using :)

Pier Unmounted

Pier Unmounted Close Up

Pier EQ6

Pier EQ6 2

I shall be powering the mount with a powertank for the initial period. Another project is making the nearby shed into a sort of warm-room, with a semi-permanent mains powered 12v feed and usb connections out to the pier. I may write this up in another thread in the future.
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Good read Matt. Looks really stable don't think you will get much vibration from it.

If it wasn't for the fact I do not have much sky to play in dew to trees to the east and house to the west I'd really think about one my self. Good job well done [emoji106]

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  • 3 years later...

Do you keep the mount on after setting it all up. If so what do you use to keep it weatherproof when not in use?  Just started buying all the bits to start mine.

Edited by dtastro
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On 08/05/2019 at 20:59, JamesF said:

Oooh, setting the blocks at right angles to each other!  Fancy!

James

I know.!!!!!!...... flying in the face of convention, or should that be "construction"? :BangHead:

Seriously though, there was method to my madness.  🤨  Available "storage holes" all around the mount. 👍  

I find I'm usually either at the door side of obsy by the controlling laptop, (from where the photo was taken), or parked on the visible seat so storage holes are nice and close to hand. The hole in the bottom block neatly holds the Nevada Power Transformer, purchased from Jkulin some months back, with the output cabling coming up and out from a side I don't frequent so little chance of accidentally snagging cables in the dark. 

I rest my case!

Regards, Les

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  • 8 months later...
On 10/05/2019 at 09:57, Wyvern said:

I know.!!!!!!...... flying in the face of convention, or should that be "construction"? :BangHead:

Seriously though, there was method to my madness.  🤨  Available "storage holes" all around the mount. 👍  

I find I'm usually either at the door side of obsy by the controlling laptop, (from where the photo was taken), or parked on the visible seat so storage holes are nice and close to hand. The hole in the bottom block neatly holds the Nevada Power Transformer, purchased from Jkulin some months back, with the output cabling coming up and out from a side I don't frequent so little chance of accidentally snagging cables in the dark. 

I rest my case!

Regards, Les

Very nice, I'm about to do the very same thing for my EQ6-R Pro in 3 locations in my yard.  Unfortunately, I can't find one location that is great views of the sky, so 3 will have to do :)

Were or are you worried about the blocks void area supporting all the weight?  I was going to put a 1/4" alum plate atop the block face (beneath my pier plate) - but if it's not needed, I'll save ~$60 US :)

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  • 4 weeks later...

Adian,

Sorry, only just spotted your post above.

Can only report that during the past year+ of useage, there have been no signs of cracking or movement in the blocks so I don't think you'll have any issues.

Bottom block is half cemented into ground and the two blocks are secured together with Evo-stick "Sticks like s**t" adhesive and a coach bolt.

Best wishes, Les

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