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Horwig

If IKEA made telescopes

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Hi horwig , just oggled your thread by chance, blimey mate you aint skimping on anything here , that thing is raising a few eyebrows I noticed.

good on yer ! most forumers are seeing you as a DIY guru, well I can tell yer, that looks quite an accurate take to me .

As to your dome advice request, could you elaborate on what you require the dome to do ?? you will get plenty of ideas if we know the criteria.

I also suggest you tap into other forums for builds not posted here.

best of luck Dan

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I once bought a bed that showed a woman building it by herself in the manual - Im definitely NOT sexist but it took me and the father in law 3 hours to assemble it working as a team.

Mrs bedmakerwoman,,,,,where were you when I needed you ???? lol

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As dear old Rolf Harris would say "Can you guess what it it is yet?"

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That looks nice.

Built a domed observatory myself many years back, really fun to do.

Whan you first get it on the track and turn it, it's a great feeling of accomplishment.:)

:)

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Yes, the track...I found some nice 20mm rollers from BNL, sold through RS, I think they are similar to the ones Pulsar use, I then tried for ages to find somebody locally with the right tooling to roll a 2.3m dia track out of 20mm od steel tube. When I eventually found one, they never came back with a price. Then whilst doing something else realised that 20mm electrical conduit was flexible enough to do the job, and plenty rigid enough for the weight, so that's my track, tried it with just the base ring, seems to work ok, probably allow some lateral slack in the bearing mounts to allow for out of true on the ring.

Carbon fibre tubes have arrived for the ota, but there's so much mess in the shed from the bits of old obshed and the timber for the new one that the ota and mount are on hold for a while.

Huw

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Great start :( I love Rolf Harris too :)

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Two hard days of woodwork later, it's starting to look like a dome, (the base frame was done last week). Hopefully I'll get the gores cut and fixed tomorrow, inbetween drinking beer and sitting in the sun!

Huw

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Now this really has been like working on something from Ikea, thin sheets of ply, and lots of small nails. Anyway, dome is complete,

apart from a coat of fibreglass for everything, and the shutter runners.

Threatening rain for the next few days, so tarp over it till the sun comes out again

Huw

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looks abit like "dark helmet" from spaceballs!

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Great stuff, Looks really nice.

Dome duilding is such fun, almost as good as the scope building bit. :hello2:

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The dome is nearly there, thanks to our great Welsh weather it took me over a month to fibreglass it. The cladding needs a coat of paint, and a door would probably help, otherwise the exterior woodwork is done.

The dome bearings work well, the eight rollers are really smooth, but lucky I used so many, as the ribs pulled the base ring out of horizontal true when I built it, so there's always a couple of rollers not quite touching. For the dome drive, I'm going to shamelessly borrow SkyBadger's system, (thanks for the help and tips Mike), and it looks like the software for it will be LesveDome. The dome rotation will be simpler as I'm using a fork, central in the dome.

On the OTA front, I'm busy making rod ends for the cf tubes, all 32 of them. The 16 for the bottom truss are made, but the big ones for the top truss are taking a lot longer, that's the one without paint in the picture, and without the fixing hole, and final machining to the top.

For the mount, the drive electronics have arrived from the states, it's a Scitech servo II

Fist light still seems an eternity away

Huw

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Great work, looks impressive.

At least it's something to focus on whilst we're waiting for the clouds to leave!

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Having bought and fired up my first ever arc welder to build a tripod of sort, I note that your welding is totally professional! Amazing work there!

Thanks for sharing this journey.

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Thanks for the compliment Jessun, there is a reason for the quality of the welding. It was made by a professional welder!!!

My welding is truly terrible, so all welding, steel and alloy, was done by someone who knows what he's doing.

Huw

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Excellent project Huw and clearly you have the rare skills to see it through - at ~5ft fl it should be quite compact. As you're building an astrograph had you thought of imaging the primary direct onto the camera and avoiding the secondary or is the secondary a devise to shorten the tube length? Interestingly I went from 12" to 17.5" homebuilt Newts and back to 12" SCT - my local seeing wasn't up to the 17.5" unfortunately ! Carry on the good work - great dome - the way to go!

Edited by nytecam

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Brilliant project - love watching the progress !

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First of all, apologies for not answering you Nytecam, I had considered not using a secondary, but with a starlight filter wheel, the obstruction would have been terrible.

Latest developments, carbon fibre trusses are finally complete, machining the 32 ends were a slog, but here they are epoxied in position. With any luck, I'll get the alloy bits of the ota off to the powder coaters next week.

So only the mount and the obsy to go...

Huw

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Just when you thought this thread had died a death, It's back!

Not that much has happened in the last five months, I was away for most of the autumn, got to travel to Australia and New Zealand, and when we came back in December it was far too cold and damp to do any work in the shed or on the obsy.

Before we went away, I got the parts for the ota back from powder coating and got it assembled. I've modified the top cage slightly, the vertical sections on either side of the focuser mounting plates are new, will help with the flex I was seeing in the focuser.

On the obsy, the wooden shutter design was terrible. In theory, the bottom section slid into the top one, and then both would go back together. In practise, the curve of the panels had flattened out, pulled by the tension in the ply sheet, and so would bind.

Not only that, but the gaps around the sides were huge, and water would be forced in when it rained from the correct direction. And lets face it, this is Wales, every direction is the correct direction for rain! I gave up on the wood, and made new shutter panels from fibreglass,

this was done at the end of September, just before going away. Their design is now simpler, the top shutter panel is now the only one that slides, the bottom one being lifted off hand. Trouble is, they're still in the shed awaiting installation, still too wet and cold to do anything outside.

Maybe with spring around the corner progress will now resume.

Huw

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those truss rod ends are excellent. how did you make them? on a lathe?

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Yes, profiles for the truss ends were cut on the lathe, then the square section machined on the mill, with the rounded end worked with a rotary table on the mill.

With 32 in total it was a real [production line!!

Huw

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Three dry days on the trot, it might be early for Spring, but it does mean that some more progress is being made.

got the new shutter parts out from hibernation, THEY FIT!!!, I never got round to testing them back in the Autumn. Now they need an edge grommet to finish them, the guide blocks from the old wooden ones should work.

The polar axis has been to the obsy for an outing. I wanted a trial fit for the proposed cover assembly, seems to work in cardboard, now to make it in ally. This will protect the RA drive gear from dirt and crud, and me from the grease on it.

Anlso the PEC sensor and its opto sensor are shown fitted to the RA worm drive.

I've been thinking about the fork balance, so have weighed all the bits for the Dec drive, the worm and wheel, motor, bearings etc. Comes to a grand total of 6 Kilos, so will have to cast some lead into the opposite fork at some stage.

Huw

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