observatory DIY rotating Nissen Hut or Pulsar 2.7m?

[Gina]

That is an incredible and very massive project - good luck - I take my hat off to you ?

[Mick J]

As above, stunning - cannot wait to see how you fit it together 

[Rusted]

Thanks for the support.

Bottom row of panels nearly finished. Then I had to fetch some more 4mm birch ply.

It doesn't go far at only four panels per sheet.

Ever onwards! 

 

[JamesF]

I'd missed this thread before now, but it's very impressive.  I look forward to seeing your progress.

James

[Rusted]

On 04/06/2018 at 12:29, JamesF said:

I'd missed this thread before now, but it's very impressive.  I look forward to seeing your progress.

James

Thanks, James.

Progress seems quite rapid now after such a long slog building the skeleton. 

The 4mm birch ply is more flexible than I care for.

Which make for dents at the screws. I may need to some filling before painting.

The third tier of panels will probably be cut and go on this afternoon.

The paddle switch and saw sled were well worth making.

Allowing the work to be both quick, accurate and relaxed.

[JamesF]

Once the dome is in place, if you poke your telescope out of the hatch it will look like a giant Dalek

James

[Rusted]

Careful! The Beeb's Over-Borgs will be suing you for breach of copyright. ?

When I were a lad.. I lived in Somerset too.

Then they renamed it Avon to drive me away.

They did the same to Cumberland.

At my age I need to be able to easily remember my own address.

Not have it changed by the time my bus pass becomes invalid!

Twirly [in exile in Denmark]   ???????????

[Gina]

I didn't like all those county boundary and name changes either though fortunately it didn't affect me directly.  I feel for those who were affected.

[Rusted]

Just another update to prove that I do step away from the computer sometimes.

Inside view after tidying up the ribs:

[JamesF]

How do you plan to lift it up onto the top of the observatory?  Or did I miss that bit somewhere?

James

[Gina]

Lovely job - coming on very nicely ??

[Davey-T]

42 minutes ago, JamesF said:

How do you plan to lift it up onto the top of the observatory?  Or did I miss that bit somewhere?

James

Helicopter ? 

Dave

[Gina]

Twelve hungry men??  Then feed them afterwards.  ?

[Rusted]

Sorry, I missed these latest posts. 

The plan is to lift the gores individually and add them to the base ring and and observation slit framework.

These would be lifted separately and set in place on the rollers in anticipation of final assembly.

Hence the use of duplicated ribs to allow the gores to be easily separated from each other.

Sealant/adhesive will be required between the gores as they are finally bolted together "upstairs."

I work entirely alone so the design has developed to make it fairly manageable by one person.

There was a bit of a wobbly when I was planning to lift the completed dome with a hired, Manitou telescopic loader.

But I feel the dome and building would be at far greater risk during one big lift by an inexperienced operator.

I have had endless practice assembling the dome and taking it down again for storage under tarpaulins.

So I do not anticipate any problems unless the wind intervenes.

I watch the weather forecast constantly and windy conditions are the norm here, year round.

A "window of opportunity" is quite unlikely so I shall have to avoid making a downwind "spinnaker" at half way. 

 

[Astrokev]

Wow, I'd somehow missed this build up to now. This is really impressive! Keep the pictures coming and can't wait to see it completed ?

[Rusted]

On 23/06/2018 at 08:53, Astrokev said:

Wow, I'd somehow missed this build up to now. This is really impressive! Keep the pictures coming and can't wait to see it completed ?

Thanks, Kev.

I too cannot wait to see it completed.

Unfortunately the ? builder is given to melting like Odo when it gets much past 72F/ 22C.

You just can't get the staff these days... 

[Gina]

I've been melting too!

[Rusted]

My 3m, 10' dome being rotated by hand

 

Scene 1 take 6:  ?

 

[Dr_Ju_ju]

Lovely movement, how much mass\inertia will the completed dome be ??  as it looks easy to move now, but when fully fitted out.....

[Rusted]

1 hour ago, Dr_Ju_ju said:

Lovely movement, how much mass\inertia will the completed dome be ??  as it looks easy to move now, but when fully fitted out.....

Thanks & a very good question. The covering is 4mm birch ply.

I suppose I could easily weigh that up since the panels are all sitting in the shed ready to go back on.

Then there are the shutters and supporting rails. Followed by several layers of paint.

I deliberately chose large, free turning, hard plastic wheels with bearings for the support/rotation rollers.

Fingers crossed it still rotates just as easily once "fully loaded." I could add more wheels if it would help.

Several cranked handles, inboard of the ring and much lower down, for easy reach, will help if I need to put my shoulder into it.

It rolls noticeably more freely once it gets going. So inertia is the larger factor over rolling resistance.

I'd rather avoid a mechanical or electrical drive system at first because it could easily become a project in itself.

[Dr_Ju_ju]

After having to mount old style broadcast turret cameras on rails\mountings etc. I wish you all the luck, I know how tricky it can be getting things moving and then to keep the movement to a set speed...

[Rusted]

25 minutes ago, Dr_Ju_ju said:

After having to mount old style broadcast turret cameras on rails\mountings etc. I wish you all the luck, I know how tricky it can be getting things moving and then to keep the movement to a set speed...

I hand crank driving a gear set [like a boat winch] or even having a cable wrapped around the dome might work.

A counterbalance weight would allow bidirectional rotation simply by reversing the crank rotation. Plenty of room for the weight drop.

Now you've got me started on the next building phase and I've not even finished the dome yet. 

[Rusted]

I checked the weight of the cladding panels at 35kg.

The shutters will probably be around 50kg total.

I could load the dome to see how that affects rotation.

Though I expect it will just be more difficult to get going.

The wheels/rollers are massively overrated for these loads. 

 

[Gina]

That's not bad at all.  A lot lighter than my rubber covered timber ROR ??

[Whistlin Bob]

Wow! What a brilliant project!