observatory DIY rotating Nissen Hut or Pulsar 2.7m?

[Rusted]

I'm afraid it's all looking a bit like a bomb site:

I have been lifting and moving massive boulders for days.

These were buried in the ground as a retaining wall for the shed's foundations.

Below the 2' [10cu.m. or 20tons] of sand and gravel I had just wheel-barrowed in.

The octagon of cast concrete footings are at last lined up at the correct radius.

Though still with variable level yet to be fixed with more digging.

What doesn't kill you just makes you exhausted.

 

 

 

[Rusted]

Using cord to run stretched lines across the octagon of footings helped confirm placement.

I could then back-fill all the gravel dug out for the footings and boulder removal.

Still need more gravel. Including some to back-fill the pier pipe around four concrete anchors.

 

[Rusted]

After sorting out the spacing and levels of the concrete footings I made a test gauge with the miter saw.

Two off-cut stumps of the 100x100mm main posts attached at 22.5° to a 108cm x 45mm x 145mm board.

I can now start mass producing cross braces to support the eight 12' [4m] high posts of the 2-storey 3m [10'] diameter octagon.

There will be three cross braces per side to act as perimeter joists fixed by two 100mm screws each.

Ground floor, obs.floor @ 2.6m high and dome ring @ 4m.

The image shows the test gauge resting on two [height adjustable] footing brackets.

The real posts will be 12' high to reach the dome ring.

Gravel chippings will be laid over the self compacting sand&gravel for neatness.

 

[Rusted]

An image of the planned observatory..

 

 

[Rusted]

Trial erection of my first two 4m [12'] posts to check safety and working methods using lashed stepladders.

Each new post is raised and leaned against the ladders' top cross brace until it can be brought upright and tied to the ladder.

Then I will add the 2" x 6" perimeter joists to tie the octagon together.

Then the ladders are moved onto the next post and the addition of joists repeated.

Timber braces will aid the stability of the structure until it is completed.

 

 

 

[Rusted]

Despite the hot weather [66F] I managed to raise five more posts and brace them with the perimeter joists. 

Now seven: View from upstairs window:

 

[Rusted]

All eight vertical posts and perimeter joists completed.

It is remarkably stiff considering it is just an outline shell.

No problem supporting a ladder on any upper component.

Now to add some more joists.

 

 

[Rusted]

Just an update: I have temporarily fitted my first, doubled 2"x8" beams onto their timber brackets.

I still need to glue and bolt the brackets into place. Presently researching a suitable "glue".

 

[Rusted]

Progress continuing: Main structure almost complete.

Now fitting larch floorboards.

The view is amazing!

 

[Rusted]

Just another progress update:

My isolated 12' high pier is now a four sided pyramid of timber 100x100mm [4x4s] bolted to carport concrete anchors/footings.

The top part will be sheathed in plywood and timber braces down below for extra stiffness.

My Jumbo 'warehouse/stores' obs. access ladder has arrived.

All aluminium, with stainless steel handrails extending 1m above the top tread at obs. floor level for easy transition.

The top tread is exactly at obs. floor level. Solid as a rock, it will eventually be resting on large paving slabs.

Now I have the ladder I can start fixing the 125mm [5"] planed, larch floorboards to the obs. floor.

The pyramidal pier required re-siting some of the original obs. floor joists.

 

[Rusted]

Hi

Just another update:

I have the DIY heavy mounting up on the 12' pier and the 7" f/12 refractor mounted.

Busy cladding the pyramidal pier with plywood for extra stiffness.

Working alone, I had to use opposed builder's stepladders to lift the massive 250lb mounting into place.

 

 

[Demon Barber]

The mind boggles!!!!!!!!!!!! What a thing of beauty ,i applaud your vision,just love it.

Regards

Mike

[ollypenrice]

New to this thread, but loving it!

Olly

[Star101]

Very interesting.

[Rusted]

Hi,

Thanks for your interest in my project. It all helps to keep me going.

Here's another image taken yesterday after I trimmed and fixed the obs. floor.

I had to be careful to isolate the 12' tall 4x4 pyramidal pier posts from the floor.

Boarding the veranda is next. Each section will run parallel with the octagon sides.

Then I shall need outer railings for safety. And a dome, or rotating roof, of course.

[Rusted]

Still progressing with the build:

Veranda now planked with larch boards.

Tried various mock-ups of potential rotating roofs/domes to ensure telescope clearance.

[Rusted]

Hi

Just another heads up to say that dome rib production is well underway.

These will be reinforced with sandwich battens on their outer edges.

Then clad with trapezoid, plywood panels rather than conventional gores.

The idea is to break up the dome's outline with facets to present a [hopefully] smaller "blot."

Paul Robinson's Geo-Dome.Co.UK website may inspire: 

Trapezium Dome calculation tools

 

 

[Rusted]

Another update: Dome progress: Halfway:

 

[Rusted]

Still making progress on 16 sided, trapezium dome:

 

 

 

[Peter Drew]

Rotating Nissen hut type observatory for a 8.5" refractor.

[Rusted]

Thanks, Peter.   

The half cylinder really has lots going for it.

Unfortunately I couldn't get your design past the "planning committee."

Geodesic was considered a bit too demanding and perhaps a bit fussy.

So we finally settled on a 16 sided trapezium dome as a multifaceted compromise.

The hope was to break up the outline against the background trees so it wasn't so [blindingly] obvious from the main road.

I set up a half hoop of white conduit as a full scale dome outline and it could be seen for miles! 

We don't want people falling off the road while rubber necking my modest, rural carbuncle.

[Rusted]

Another update: The veranda fencing is up and is quite sturdy. I shall add a handrail for extra stiffness.

I clad the walls of the octagon building and observatory with lightweight tarpaulins for a bit more shelter.

The folding chair is standard size and planted in the doorway for scale.

The blob on top is my massive Goto [GEM] mounting under cover.

[Swoop1]

Fantastic work Rusted. I can't wait to see the finished article. I bet it will be visible from space

[Rusted]

Thanks, but I'll be quite happy if space was visible from down here.

[Rusted]

Might as well add another update:

The 'flats' for the trapezoid panels have been cut on the doubled ribs and the vertical braces cut and fitted.

The observation slit is framed in doubled 16mm birch ply and propped securely while I knit it into the dome's skeleton.

Flats will be cut on the observation slit arcs for bi-parting shutters with facets to match the rest of the dome.  

Meanwhile I have been using the raised octagonal platform for solar H-alpha with my 6" refractor on my big DIY mounting.

Never underestimate the sheer amount of work [and expense] involved in building ANY dome!