Plywood Dome and DIY Pier

[MikeG247]

Hi all. I thought I'd share with you the build of my new observatory. After months of planning I started a little over 2 months ago by creating a rough drawing in AutoCAD to obtain the dimensions I needed. The frame is constructed from 18mm Plywood, 2 layers thick in places, and has a 4mm plywood skin. All the components were cut using a jigsaw and glued, screwed and fixed together using aluminium brackets. Once the dome was complete I constructed a hexagonal base with 8 castors on the top for the dome to rotate on. The attached image shows a picture diary of the dome being constructed. The observatory has a diameter of 3.0 meters and stands about 2.8 meters tall.

Once the observatory was complete I fabricated a pier. This was built using 6mm steel pipe with a diameter of 168mm. I welded a flange top and bottom. I machined a top plate from 10mm thick aluminium and an adapter to mount my NEQ6. I concreted a base setting 8 x M20 bolts into the wet concrete. I didn't weld any webs or bracing to stiffen the structure as considered it would be pretty rigid without any and if needed I could remove the pier and add them at a later date. The pier seems very solid so don't think I will be bothering.

[swamp thing]

Very nicely constructed indeed. Great job.

[MikeG247]

Thank you

[RikM]

Looks smashing

[nightfisher]

Highly impressed, very practical and looks superb, thanks for sharing

[8kids]

A fine piece of joinery, well done.

[avtaram]

Looks great. A real good job.

Avtar

[Baselessum]

Great build there, looks fantastic

[MikeG247]

Thanks for your comments guys

[Ibbo!]

very nice

the more I see this sort of thing the more I want one

Steve

[Bizibilder]

Exellent and beautifully made. What did you use to seal and finish the ply? Looks like yacht varnish?

[MikeG247]

I considered yacht varnish but in the end went for 3 coats of Sanolin extra durable clear coat.

[101nut]

Pity, I can't see the attached autocad file ... :-)

Looks really smart.

[bottletopburly]

Smart job once again mike

[wxsatuser]

Sweet :icon_salut: :icon_salut:

[Teslar]

Interesting I've got a sky at night set of plans for an almost exact copy of yours. I currently checking price availability of the parts listed in the documentation. The plans are a little indistinct with regard to the way the dome attaches and how it is sealed so I'd be interested to hear your solution. Also what mechanism are you using to prevent lift off in high winds

[Obsession 30]

Looks very smart, you've done a great job

[JamesF]

That's very pretty indeed.

James

[MikeG247]

just tried but it wont let me upload the cad file so i'll upload it somewhere and post a link.

Teslar it runs on 8 castors but also has 4 small wheels inside running on the inner edge of the bottom ring to stop it moving sideways and dropping off the castors. Securing it for high winds is the only job I have left to do but was considering 3/4 fixed clamps similar to the removable ones I'm curently using when I'm not using it. As for sealing it as you'll see in this picture i have attached a stainless steel strip inside that the felt under the castors laps up onto preventing water from running in.

[MikeG247]

I've uploaded a DXF version of the AutoCAD file here

And a DWG version here

Like I said above its only a rough drawing done to gain the dimensions I needed but Its there if you want to have a look

[Teslar]

Thanks for the photo and info I'll look into that

[Astrobits]

Excellent job that. Looks just like the one I am making at the moment!!!! Dome is almost identical but details are going to be a little different I expect.

Nigel

[teleskopjo]

I suggest you place a timber spacer block directly underneath the clamps so that when you tighten up you do not flex the base ring - which I understand you made it in two layers of plywood on a 3m dia. dome? Fantastic workmanship!

[101nut]

I've uploaded a DXF version of the AutoCAD file here

And a DWG version here

Like I said above its only a rough drawing done to gain the dimensions I needed but Its there if you want to have a look

Excellent!

AndyG

[MikeG247]

I usually clamp almost directly over a castor to avoid any flex but just put the clamp anywhere for that picture. Yes the base ring is 3.0 meters in diameter, 100mm wide and made from 2 layers of 18mm ply. I overlapped the segments when glueing together and used 30mm screws clamp them together