Homemade observatory dome + accessories

[skybadger]

My first dome had a lift off lower piece with a moulded overlap on the top segment. The top just rested on Teflon strip at the edges and was retained using internal wheels running along the inside edge.

The current one has a lower piece that slides under the top when pulled up using a cable..Again the top rides on a Teflon strip. I did design a shutter running on allloy edging but it gets complicated and frictional if not used sparingly.

Mike

[Davey-T]

A couple of good YTube videos on fiberglassing stuff if you do a search.

Dave

[choochoo_baloo]

Sorry Mike, please could you elaborate on where/how the "internal wheels" are fixed? Also could you provide a link to where you bought them?

[nytecam]

Interesting project Choochoo but I don't see what size your dome will be - perhaps I missed it! Size matters and usually matched to the 'scope it is to house.

Down the years I've built 6 domes [never a ROR!] two each for club, self and buddy from 12ft to 6ft - the latter for my 12" SCT @ http://home.freeuk.com/m.gavin/mydome.htm.

If recommending a dome type today I'd go for an octagonal dome like my buddy Ron @ http://home.freeuk.com/m.gavin/rondome.htm- it uses regular sheet ply for the minimum cutting or waste and appear spherical in profile eg doesn't appear octagonal! It's weathered with modern acrilic paint direct on ply and works just fine. It has the classic up-and-over shutter [40%] parked on fixed back section [40%] with hinge forward front section [10%] with good view of zenith.

IMO as an architct bi-parting shutters can act as a sail and prone to yaw unless perfectly engineered. Keep it simple !

Good luck in your project ;-)

Nytecam

Edited September 2, 2015 by nytecam

[Horwig]

Thanks Huw, yes that is exactly what I'm after. Could I just check that I've understood you correctly? Please see the attached sketch of your upper shutter in cross section.

Shutter1.png

If correct, I assume that you have no problems with smooth running/friction?

Yes, essentially correct. The shutter rides directly on the ali strip, without the blocks on top, I did not use any teflon between the two, but it slides relatively easily. In hindsight, a counterweight system would be useful, as it's quite a weight to control, and when fully open it has to be closed from the outside.

Huw

[skybadger]

Hi choo choo -

the wheels just press against the inside lip. So the door slides o the outer rim and two arms come through the slot and hold wheels against the inner rim to stop the door blowing off.

The ones I have are the rubber tyred steel wheels from RS or Wixroyd, bought in a bag of 10.

Mike

[hughgilhespie]

Hi Choo Choo,

Just for interest, I have uploaded some pics to my gallery showing my dome driver motor. There is also a short video of it in action.

Regards, Hugh

[choochoo_baloo]

Just had a look through Hugh, impeccable attention to detail and workmanship. You've set the bar high!

[choochoo_baloo]

Hi choo choo -

the wheels just press against the inside lip. So the door slides o the outer rim and two arms come through the slot and hold wheels against the inner rim to stop the door blowing off.

The ones I have are the rubber tyred steel wheels from RS or Wixroyd, bought in a bag of 10.

Mike

 

Great thanks Mike. Do you have any photos to hand of this shutter system - I'm not quite sure what you mean RE 'arms though the slot'?

Thanks in advance,

Matthew

Edited September 3, 2015 by choochoo_baloo

[skybadger]

Not yet - youll have to give me a coupe of days..

[choochoo_baloo]

Have you had chance to take those photos Mike? Thanks in advance.

[skybadger]

Here it is - took longer cos I forgot.

Wheels in interior - on bottom sliding section which slides under the large section.

View of overlap between large and small sliding sections.

Hope this does what you want.

Mike

[choochoo_baloo]

Thanks Mike for the upload. Have been away from the forum for a few weeks.

Components have arrived from wood router at last, so can begin dome construction.

[timfrench14]

www.ulo.ucl.ac.uk