New Observatory or what I like to call it, getting ready for retirement.

[anthony2302749]

Hi all

After building several small observatories, I thought it time to invest in a proper dome observatory. Something I can settle back and enjoy in my future retirement.

So where have I been in regard to DIY observatories. First endeavour was a garden shed converted to a roll of roof for a 10" Newtonian on a Samson EQ mount in Wagga. Failed to use this due to joining the Army. Second endeavour was as Roll off box design for a Meade 10" LX200 Classic. It worked well for about 12 months but then we sold up and move house.

Third endeavour was again a garden shed converted to a roll of roof. This housed two telescopes, an ED120 and a Meade 14" LX200. Failed to use this after a period of time due to working in the telescope sales business. Didn't feel like doing astronomy after talking about it all day with customers. Forth endeavour was converting the above roll off observatory into a structure that would rotate. Something similar to a ScopeDome. This housed a Skywatcher 16" Goto Dob, nice telescope but crap observatory.

Final endeavour was back to the Roll off box design, which like the Mill Park version works a treat. Currently house a Meade 12" LX200GPS. During this build I reinstate the pier on the original pier foundations I created when I did the Roll off Roof observatory. It is a substantial piece of concrete, coming in at about one cubic meter. I cleaned and level the top, put in Rebar and used a 10” Storm water pipe as a former and filled it with concrete, very solid.

I have added some photos for a bit of a visual journey of my past endeavours.

Where to now, well after some research and quite a bit of Googling I have settled on Observatory Dome by Charles Baetsen (https://va3ngc.weebly.com/obs---dome-1.html) which includes a plan in PDF format. Currently I am in the process of drafting a scaled up the design. I am working on an outside radius of 2.61m and an inside radius of 2.43m for the dome. This will sit on a square support structure with surface area of 6.8m2 . Overall structure height not to exceed 3m, so as to stay inside council building guidelines so as a building permit will not be required. I still have the paperwork ready in case I need a permit.

Also have fleshed out ideas for the roller, shutter and even a drive system to move the dome. Anyway, tomorrow I will be starting to route out the ring and frame for the dome.

Stay tuned and see you at the next post.

[anthony2302749]

Before I get on to what was achieved today here are some images of the pier being resurrected.

[anthony2302749]

As I have mention, have scaled up the original plans. Some images of my redraft work.

[anthony2302749]

The dome design requires several large plywood rings to be constructed. These are created from arcs of plywood cut to the correct radius and then laminated together to form said ring. I cut out 20 today, enough for 3 rings which will be the base ring for my dome.

I made a tangent arm for the route to allow me to cut out the correct radii. After a little hiccup at the start due to bad maths, one sheet of plywood met its feint.

[anthony2302749]

Today's task was to trim and stack the plywood arcs to form the dome support ring. To get the desired curvature I used a bit of timber as a tangent arm which was measure and drill for the inside radius of the dome, which in my case was 1215mm. This was nailed between the decking boards into the joist below, this allowed me to align the plywood arcs nicely.

The process after this was to align each plywood arcs joint using the tangent arm as a guide, trim if need to get a nice butt joint and repeat. This was done for each of the three layers. Total thickness of the Base ring is 36mm. By the way the bricks are there to hold everything together

Point of note is that the routing was so well executed the inside radius of the ring was near perfect.

Tomorrow's task is the to, level, glue and clamp.

[Tinderboxsky]

Clever use of your deck to assist with fabrication.

I am following with interest.

[Leo.G]

Quite the journey Anthony. The new build is looking very nice and I was so happy to see the real drawing equipment just like I learnt to use, not a computer CAD thing. My son can do it faster with full 3D rotation in some engineering program complete with stresses (with no training) but I did 3 years of drawing training with an engineering course and I like my manual stuff, I can't use the computer thingies.


What glue are you using?
I like bondcrete myself, it's basically PVA but waterproof.

[anthony2302749]

PVA, didn’t think of Bondcrete. Extent of my drawing education was at high school. The compass set in the picture is my original from high school, it’s going onto 42 years of age, still in good condition for a Czechoslovakia made set.

[anthony2302749]

So, after a trip to the market for some lovely crepes, then Bunnings, I got started with laminating the first layer of the dome support ring. This meant I had to unstack yesterday's work, raises the bottom ring up on to 25 blocks of 90x45x100mm timber so I could clap the work. Also raised the tangent arm.

I happen to have a stapple gun, hence the compressor in the picture. I realigned the plywood arcs, glued, then clamped and then tacked with two staples. This was done on all seven joins.

Next stage was to glue and laminate the second ring into place. By the way, always good to number your pieces to help with assemble. Glue was applied to each surface which will be in contact with each other. Plywood arcs were then placed into position, overlapping the joins on the bottom ring, clamped and screwed into place. Repeat 7 times.

While the decking is reasonably level, I still went around the dome base ring with a spirit level and made small adjustment to ensure it is sitting level as possible.

Depending how I pullup after work this week I may do the last lay before next weekend.

Cheers

[anthony2302749]

This part has been quite annoying part of the project. I have scoured the internet looking for a lower profile castor/roller with bearings. Most low profile castor here in Australia are roughly 80mm high and anything suitable outside of Australia was out of the question due to cost and other reasons.

I may have come up with a DIY solution, call it an epiphany while enjoy a morning coffee. My solution to a low-profile roller is to use a 1" aluminium tube (which I have plenty of due to ATM project) inserted with two 22mm bearing at each end, 8mm axle (again plenty of). Whole assembly fitted into the top of a PVC pipe cut to length. I am thing of rapping the rollers in heat shrink tube as a form of rubberization.

This roller idea will allow me to set the gap between the dome base ring and the observatory top ring to any height just by adjusting the length of the PVC Pipe which is a cool idea. The rollers will be recessed into the observatory top ring to keep with the low profile. The top of the rollers should not need to sit any higher than 25 to 30mm above the observatory top ring. Just enough space to allow the adjustable steel carriage to fit with out binding.

Also help with keeping the whole structure under 3m. Other reason is I want the entrance door to be tall as I can get it for easier access, back is not getting any younger.

Also pickup from Bunnings today was four of the Rolltrak Adjustable Steel Carriage and Acetal Roller, thought it would be a good means to keep the dome aligned. Hope four is enough.

Anyway, the two pic upload is proof of concepted of the roller idea and the Rolltrak Adjustable Steel Carriage And Acetal Roller.

Cheers

[Leo.G]

I have a set made in Czechoslovakia and it's amazing quality.
Though I recently did something stupid with my Rotring compass from my several hundred dollar drawing set (including pens) and I can't get the tiny part anywhere. It's an old set 25 years or so but in new condition but the compass itself is no longer available or the parts to fix it (the small thing which holds the lead or needle).


The roller you've made in the last image looks good but how much load will be on the PVC pipe?
I think it would be a possible wear point where the axle goes through the PVC but that would be load dependant.

[croweater]

Hi , +1 for Leo's comment about axle/pvc wear. Maybe a metal collar could be glued into the pvc pipe to fit the axle into. Anyway watching with interest Anthony.
Cheers, Richard

[anthony2302749]

👍 it is a concern particularly flexure as it is easy to squeeze the tube and deform the PVC so not a good idea to use standard 50mm PVC. However was back at Bunnings today getting some stuff for work and I had a look in the Plumbing section particularly for PVC which should stand up to the rigours of supporting the rollers and dome.

Found a 50mm Pressure PVC Solvent Weld Coupling which has 5.5mm thick walls so should be strong enough for the task at hand. I will make a Mk 2 version over the next night or so and see how it works.

Other alternative is aluminium tubing or some other method.

Cheers.

[anthony2302749]

Going to try 50mm Pressure PVC Solvent Weld Coupling with has a 5.5mm thick walls with should survive the rigours of supporting the rollers and dome. Mk 2 prototype should give me a good idea if not aluminium tube would be the next idea.

Cheers

[croweater]

Sounds well worth a try.:thumbsup: Would be easier and cheaper than aluminium.

[Leo.G]

Definitely easier and cheaper than going with alloy but the 5.5mm wall thickness should hold up a lot better to wear.
The other simple solution I've used myself is RivNuts (rivet nuts). Now that may have you scratching your head but they are available in alloy and steel (possibly stainless steel too, I'm not sure), if you pop them in then drill the thread out where the steel axle is going through they work well as a sleeve/bush to prevent ware on the softer PVC piping and are cheap and very easy to work with.
If you don't have a rivnut gun they can be secured using a bolt and washer arrangement and I believe there's a lot of information on doing exactly that available online.
Food for thought.
Remember to pop them in place before drilling/grinding the thread out and a smear of grease (lithium spray is good and often cheap).
Were I copying your idea I'd probably go all OCD and drill a hole in the shafts for a grease nipple and a small collar on the axle but I have a metal lathe handy. Come to think of it I'm such a lazy b@stard I'd be more likely to give them a squirt of silicone spray or WD40 when the squealing started hurting my ears. I have to be honest. I do like to think I'd do everything properly but sometimes cheap, easy and no fuss wins, only 80% of the time though, the other 20% I'm pedantic (that means my son gets in my ear).
Gotta be honest with at least myself!
I use to be particular about everything until an OCD perfectionist plumber friend informed me when I saw him doing a rough plumbing job "I've had to accept it's not a perfect world"
I was shocked, this guy was the perfectionist of perfectionists.


I told you my son would get in my ear, he's smarter than I am!
He just mentioned the issue of getting two sleeves square to each other for an axle. Now I'm a quick thinker (it's the only thing I can do in any sort of reasonable time frame) and came up with an instant solution, if you use a suitable length bolt (or threaded rod), a sleeve and a few nuts and washers you can align the two Rivnuts and compress them into place together. Then you only have to drill or Dremel the thread out reasonable square.

[anthony2302749]

Well, that didn't take me as long as I thought. The 50mm Pressure PVC Solvent Weld Coupling is 70.7mm long and 70.7mm in diameter with and internal diameter of 60mm, which equates to 5mm walls. Slightly larger in diameter then I want but it will do.

Process was pretty straight forward, part the 50mm Pressure PVC Coupling in half on the lathe. Marked and drill 4mm below the top edge out to a diameter of 8.5mm, added a couple of 4.5mm spaces and jobs done on Mk 2.

Roller Mk 2 work very nicely and looks solid compared Mk 1, probably pin the axle into place which should be straight forward on the drill press.

P.S. Having the correct tools make the job easier.

Cheers

[Leo.G]

Looking good Anthony!

[anthony2302749]

Yep, know what Rivnuts are, and interesting ideas keep it in mind if there is a Mk 3 version. I don't think I will get a lot of wear on the PVC. The roller are fitted with 22mm sealed bearing so the 8mm axle can be pinned in place as it does not need to rotate with the bearings. The main issue would be the downwards force causing wear and tear on the aluminium axle.

Probably should create a Mk3 with a Steel axle. Thanks, Leo for your feedback.

Cheers

[Leo.G]

With the 5mm wall thickness and the bearings I don't think wear is going to be a problem at all for some time, depending on the load.
I like people who come up with easy solutions for complex problems, it's what I've done my entire life and my son is even smarter. We often use what's laying around for whatever we have to do. The engine crane which removed the 4 litre engine from my Falcon when it blew up I got it bored and rebuilt it myself) consisted of old water pipe welded together and a rotating head utilising a Ford head bolt. A chain block hung from it and the main frame was chained to the steel fence posts. It worked like a dream, until I lifted my big Lincoln TIG welder I bought used from the TAFE with it, damn, my engine was supposed to be around 250KG, I have no idea how heavy the welder is but the 7x4'6 trailer didn't like the load travelling the thing. It now sits in a friends farm shed because I didn't have 2 phase power and was too lazy to design and build something to run it from my single phase house wiring (qualifications in electrical and electronics, and welding and other useless stuff I've long forgotten).
I'm looking forward to seeing the progression of your build!

[anthony2302749]

So, over the last two days I have been work on two parts of the observatory project. This thread is about the final stage of completing the Dome base ring which includes the lamination of the last plywood layer, patching the screw holes and joints with builder's bog, sanding and first coat of 4 or 6 of marine varnish.

Why marine varnish, I thought it was a good idea as it will seal the plywood and give a nice surface finish for the rollers to run on.

Cheers

P.S. I did go around and check and relevel the dome base ring to ensure it is with in tolerance and is somewhat level in all cardinal points. A process I will keep doing until the final plywood cover is applied.

[anthony2302749]

The other part of the project that I was working on today was the constructure of the Shutter frame. Same routine as with the dome base was to cut out 13 plywood arcs with an outside radius of 1258mm. Lay them out and align with a tangent arm.

Was thinking of constructing the ring on the pavement but with the treat of rain I move to the garage which was my original plan. The good thing with my garage it that I was able to use the expansion joints in the concrete to centre the tangent arm right where they cross at 90 degrees.

I only had to laminate two layers of plywood together, so the process was quite quick and having done it multiply time it get easier with the trimming, gluing and screwing.

Final task tomorrow is to divide the ring into two semi-circle than hopefully put some studs in to form the opening and attach it to the dome base ring. This will depend on the painting.

Cheers

P.S. The Shutter opening was scaled up to 690mm due to the fact I have scaled up the diameter of the dome from 2.3m to 2.6m

Also here is the link I used to get the right radius for the shutter frame. https://ambrbit.com/TrigoCalc/Sphere/Cap/SphereCap.htm#cap

[anthony2302749]

Need to get the car back into the garage so decided to cut the shutter frame in half early.

Using the tangent arm, I made sure the Shutter fame ring was centred, then ran a string line across the circle ensuring it passed over the centre to give me a line to cut by. Also ran a string line 90 degrees to the first to mark in what will be the top of the semi-circle, tape measure help with squaring the lines.

Once done, cut line marked in then a quick cut with the saw. End result to evenly matched semi-circle.

Very happy with the result.

Cheers

[anthony2302749]

Today's part of the project was to construct the Shutter frame proper. First task was to recheck the maths to ensure the height of the frame is correct in relation to the dome base ring and that the future dome ribs will fit correctly (I have an idea for that but have to wait till next weekend). Removed 36mm from each end of the Shutter semi-circle. After this task I got the desired height of roughly 1348mm (1258mm height of Shutter semi-circle plus 90mm for the support blocks not including the window packers)

I then made 3 by 1" thick plywood studs (Not entirely happy with the end result of two, they may get the flick) to secure the Shutter semi-circle parallel with each other and squared front and back. Final task was to add additional studs of 42 x 19mm Pine which I repurposed from an old screen which I had made years ago, and which was heading to landfill.

The Shutter width is 690mm (27.1") with and opening past zenith of 178mm (7"). Rule of thumb for the opening past zenith is half the aperture of the telescope diameter. Which of cause came from the web some were maybe Cloudy Nights.

Cheers

P.S. The Dome base ring got a final coat of marine varnish, four coats in total. Tomorrow with the help of my son, going to flip the dome base ring, centre, level and mount the Sutter Frame.

[anthony2302749]

This evening, flip the dome base ring, centred, levelled, ran a string line to obtain equal halves. Then measured ran a string line 90 degree to the first to obtain equal quarters. Remounted the Shutter frame and centred.

Still not liking how the Shutter frame end pieces which sit on the dome base ring look, I think I can come up with a neater solution.

Cheers

[Leo.G]

That's looking AMAZING!
The mention of marine varnish, I learnt a long time ago the quality in the timber and finish is what makes it last. I've tried the cheap options in the past for various projects, never again where timber and finishes are concerned.
Ah, my sister is visiting Melbourne from Queensland and sent me photos yesterday of clear blue skies, I dream of those things but rarely experience them, it raining again here for the past 3/4/5/...days.

[anthony2302749]

The long weekend is a pond us, and for me more construction work on the dome.

Today's effort was to complete the pair of 90-degree Ribs. This of course involved more routing however the math on this was easy as the ribs are the same radius of the base ring.

So, for the pair of 90-degree ribs I need to cut out 6 plywood arcs. I started to assemble one by placing the plywood arcs on the dome base ring but found it didn't work the way I hoped. Only advantage was cutting the correct angle of 90-degree ribs which mate to the shutter frame. Went to method B, that is clamp two plywood arcs together, line the top to the shutter centre and line the bottom to the quarter mark, adjust to the desired length by loosening and re-clamping. Once I was happy, I added a small fudge factor in of 5mm in and glued and clamped all pieces together.

Once I had completed the first rib, check my work against the shutter frame and ring and made adjustment by trimming each end of the Rib until I had a nice fit. Rib one became templated for Rib two and I knock it out very quickly.

Once I had two complete Ribs, I clamped them on to the Shutter/dome ring Base. Made some further corrections in measurement regarding equal halves and quarters. After this I started to make 90-degree Blocks to use as brackets instead of metal ones, I think it looks nicer. Also gives me a point for clamping the plywood cover later on.

Cheers

[anthony2302749]

Today's task was to fix the Shutter frame and 90-degree rib to the dome base ring. Plus, route out and assemble four 60-degree ribs.

Same method was used for 60-degree rib as with the 90-degree rib. But as the 60-degree rib attaches lower I need to measure down 210mm from the top of the shutter frame, more maths. Using a bevel square, I obtained the correct angle so that the rib sits flush to the shutter frame. Then with the help of some clamps I adjusted the 60-degree rib until I got the right length and top and bottom of the 60-degree rib sat flush. Glued, clamped and screw the rib together ensuring to leave a few extra millimetres as a fudge factor.

Bevelled the top end to get a nice flush fit, trimmed 5mm of the bottom and the first 60-degree rib was complete and ready to be used as a template for the other three.

The other three ribs have been constructed and are sitting on the decking.

Cheers

[anthony2302749]

Since my last post which wasn't that long ago, I have bevelled and trimmed the 60-degree ribs and clamped them into place. Beginning to look like a dome. Did make one cutting error with a rib, cut the bevel on the wrong end from where I had marked it, obviously forgot to "measure twice, cut once". However, had plenty of fudge factor to play with, so no real concern.

Next task is to fix the 60-degree ribs to the Shutter frame and dome base ring and get started on the four 30-degree ribs.

Cheers

[anthony2302749]

After a day visiting the Lume and lunch with the family I only had time to fix the 60-degree ribs into place and flesh out the final 30-degrees Ribs.

Same process as for the 90-degree ribs. Remeasure, drill, glue and screw the top of the 60-degree rib to the shutter frame and then remeasure, glue and nail the bottom of the 60-degree rib to the dome base ring. Job done.

Also fleshed out the last of the ribs, that being the 30-degree ribs. So, tomorrows job is assembling two pair of 30-degree ribs and hopefully have them fixed in place by the afternoon.

By the way, three sheets of 2400x1200x12mm plywood nearly made the distance had I not made some erroneous cuts on the second sheet while constructing the shutter frame. The piece of plywood that were intended for the shutter frame are now being repurposed as plywood brackets as seen in the pictures.

So, will need to buy roughly a 1200x1200x12mm plywood sheet to construct the ring that will be used to support the rollers and sit on the observatory wall structure. Will worry about that later.

Cheers

[anthony2302749]

So, today's effort was to complete 30-degree ribs but alas I ran out of plywood to finish the last rib. What I did get to complete today, well at least three 30-degree ribs. All trimmed, glued and screw into position using the same method as all the other ribs in this build.

With the use of a plane and belt sander I bevel the top end of 30-degree ribs so that the sit flush with the Shutter frame. Pretty pleased with my carpenter skill so far.

Cheers

[anthony2302749]

Last rib when in this morning marking the end of the dome frame construction. Also sand down each rib and filled in the screw holes to get the frame ready for covering.

[anthony2302749]

So, with the finishing of the dome frame the next step is the covering of the dome. For this task I am creating three cardboard templates to be used to help cut out the 3mm plywood sheets. Two templates are complete the third one will be done tomorrow. By tomorrow afternoon should have several plywood panels cut out and attached to the dome frame.

Cheers

[croweater]

Looking good Anthony. You re going to have to restain your deck when you're finished :P
Cheers, Richard

[anthony2302749]

:thumbsup:

[anthony2302749]

So today I was hoping to get a bit more done in the way of applying the plywood sheeting to the dome frame, however things did not go to plan.

Making the template was relatively easy and cutting the plywood sheeting not much of a challenge, however affixing the first segment went south quickly. In my mind I was hoping to be able to fold the plywood over the shutter frame, in practise I destroyed a good piece of ply. So back to the drawing board for a new idea.

The solution was to rip a piece of 40x19mm pine with the circular saw set at an angle of 22 degrees. Good thing is that the pine been sitting out in the weather and therefore quiet damp which makes it easy to bend into shape. Glued and clamp new 22-degree piece to the shutter frame, tacked with stables. Modified the template, cut out a new piece and put it into position once the glue had time to dry. Success, the piece went on nicely.

So, in the long run I manage to get two pieces attached today.

[anthony2302749]

So, since my thread I've been hard at work installing the 3mm Plywood panels. Let's say it is the least enjoyable part of the build as there is a lot of fiddly adjustment along with a bit of cursing and blood, put the drill into my finger.

Anyway, while I endeavoured to get the templates correct, thing didn't fall together as I intended hence the fiddly adjustments. The 22 degrees bevels were installed along the shutter frame, finish of the last two 30-degree panels. Then moved on the last three 60-degree panels (did one last night), these panel were a pain to do in regard to getting them to fit somewhat in line with 30-degree panels, a bit of trimming was required. So, all up installed 5 panels today, all glued screwed and stapled on.

Four more panels to go with one sheet of 3mm plywood left, will I make it.

Cheers

[Leo.G]

It's looking amazing Anthony but watch out for the finger and don't let it get infected. I've done it more times than I'm prepared to admit.

[anthony2302749]

Well skipped some formality this evening. Rip the last piece of 3mm ply for the last two panels. Ended up short by one piece, so need to purchase another sheet this week.

As you can see, I have completed one full side of the dome. I didn't get too pedantic with how well the panels aligned with each other, a mm or 3 is not going to be the end of the world. As for glue I have been using liquid nails as the adhesive, this was applied to the rib before the panel is placed into position. The panel was then clamp top and bottom and stabled down with furniture staples. (Tip I picked up from another thread on Cloudy Night, plus I own a Staple Gun plus compressor. Quick work.)

Future work will be to complete all the panelling, sand and fill joins with Builders Bog. More sanding than fiberglass all the joins, more sanding, than paint with good quality exterior paint.

Still a long way to go, plus there is still the shutter to design and build.

Cheers

[anthony2302749]

Today picked up the last sheet of 3mm plywood from Bunnings. To fit it into the car I had to cut it in to 3 pieces so took the necessary tools with me. Anyway, long story short, I was about to cut up the plywood only to find I left the circular saw battery at home. Thank God the tool shop had a demo battery for me to use.

So, after work I installed the last panel to complete both sides of the dome. Also place the first panel to cover the rear shutter frame of the dome. Another small panel and the dome will be completely ready for the next stage, which is to sand the joints and fill with Builders Bog.

School holidays next week so I will have more time on the build, progress will be much quicker.

Cheers

[AstroViking]

That's a great looking dome, Anthony. I can't wait to see how the rest of your build goes.

Cheers,
V.

[anthony2302749]

Today I completed the last bits to finally have the dome frame fully covered. This led me to do a bit of a clean-up and pack some tools away before I started the sanding.

Trimmed and sanded back all-over hanging plywood and lightly sand all joins. Now currently filling all joints with Builders Bog before some more sanding.

Cheers

[Leo.G]

That's looking very nice Anthony!
Bunnings do cut but locally none of the guys bar one I spoke to the other day understand kerf thickness, 3mm for the saw blade. I wondered for years when every job was 3mm short till I picked up on the guy reading the tape measure equally right to left and left to right. His answer was "none of the tradies complain" and I explained it wasn't their own project and what's 3mm to them or the customer but went on to explain at well over $100 for a single sheet of 12mm marine grade play I wanted it cut accurately, not 3mm short (which it was).


https://www.thehandymansdaughter.com/saw-kerf/


I guess I studied fabrication engineering along with a lot of other subjects (too much time on my hands on disability pension) and my teacher would have failed me if I failed to allow for the kerf when cutting and welding materials.


What sort of bog are you using?
Are you going to tape it first with the fibreglass tape (self adhesive) like what is used to join gyprock?
It holds the filler in much better and isn't overly expensive.

[anthony2302749]

:thumbsup:

[anthony2302749]

So, since yesterday the dome joints have been filled with builder's bog and allowed to set. From lunchtime today I have sanded all the joints down to a nice smooth finish ready for fiberglassing, may wait for the holidays before I start that process.

Other than the fiberglassing the shutter is the next major task. So, the plan for this stage is to cut out the appropriate quantity of plywood arcs to form the frame for the two shutters, top one rolling and the bottom one connected by a hinge, simpler to the Sirius observatory dome.

For the tracks which the top shutter will run on I plan to lay aluminium flat bar along the shutter frame opening, then a strip of timber then another layer aluminium flat to create the track for the shutter to roll on. As for the roller, I have a quantity of 20mm Flat rollers for the job.

Cheers

[Leo.G]

I'm not sure if it's of any benefit to you in any way but the timber sandwiched between 2 strips of aluminium may be a little restrictive, then again it may not and I may well be misunderstanding the design you've described, it happens with my brain or what's left of it..
In the past with a sliding timber surface I attached the tongue out of yellow tongue particle board flooring and it gave it a nice smooth surface for the panel sliding movement up and down. It was only a sliding shelf in a complex computer table I designed and built but with the plastic or whatever it is it made for a very nice sliding finish. Bunnings sell the tongue on it's own, worth keeping in mind.
It's a polypropylene strip:
https://www.bunnings.com.au/poly-eiger-4mm-3-6m-yellow-poly-cable-feeder_p4430566



Are you going full fibreglass shell over the dome?
I don't like playing with fibreglass but have canoes and have had no choice in the past, good luck with it.

[anthony2302749]

So :thumbsup: to Leo.G for this part of the project. I have been considering various options for creating the tracks for the shutter to roll along when opening and closing.

These options included using aluminium flat bar laminated together. Example, one piece of 25mm wide flat bar then several 10mm wide flat bar stacked to give a track width of 20mm then finished off with 25mm wide flat bar. Probable would work but costly.

Other option was again using a piece of 25mm wide flat bar but instead of 10mm wide flat bar I would be using timber then finished off with 25mm wide flat bar. Problem here is finding a suitable piece of timber fit for purpose.

The final option which I have gone for is to use a strip of 30mm colour bond steel scrounged from a building site, 5 strips of yellow tongue, stacked and a piece of 25mm wide flat bar to top it off. All up a cost-effective solution to a problem.

The Yellow tongue was Leo.G idea:thumbsup:

Cheers

[Leo.G]

I'm glad to be able to help Anthony!
I've found it to be a valuable resource in the past for multiple purposes and always used to salvage it when given the opportunity, it allows other materials to slide nicely and if it does become a little stiff a little dry lube stick will help.

[AdamJL]

The weight of this thing... gotta be a bit on the heavy side! How are you going to lift it out? Or are you going to build up a brand new obsy out from underneath it? :D

[anthony2302749]

Hi Adam

Put the dome through a lift test this afternoon with me on one side and my son on the other, surprisingly not that heavy, so it could be a two man lift. But the plan is to call in some help and with the help of several dollies to wheel the dome around section of flat yard and the lever it up onto the observatory. Propping the levers with ladders once level and then slide the dome on to the observatory. Shouldn’t be too difficult.

Cheers

[MTregz]

That's coming along well!

[anthony2302749]

So, for the pass week been routing out the bits and pieces to construct the Sliding Shutter for the observatory. You would think after the number of cuts I have done with the router this would be straight forward. No, had to recheck my math to get the right radius. Once that was done everything fell in place and I am happy with the results.

This piece of Sliding shutter runs on the inside of the tracks, still finalising the roller bearing design. Kind of leaning towards two more plywood arcs outboard of the inside frame which will be fitted with the roller bearing. These will be affixed to the plywood cover via screws so to be able to remove shutter when need be. A future photo of the idea probably will clear up any miss conceptions.

Cheers

[anthony2302749]

Same day different task, Fiberglassing. Back story here is the ability to find a suitable local supplier of fiberglass and epoxy resin in my local area other than Bunnings, after countless hours on google came up zip.

End result purchased a roll of 150mm x 50m fiberglass tape from a company up in Sydney, more then enough to do the job. It was on special for $15 which is a bargain, but postage was $38. Still, three days later it was on my front doorstep which was very quick delivery. As for epoxy resin I caved in and got two tins from bunnings for $37 each.

Fiberglassing, like sanding probably is not the most favourite part of the construction. While I have fiberglass before it's still a learning curve and after reading the instructions and guesstimating the quantity need to do one strip it turned out I made enough for two.

So, from this little exercise I will assume that 200ml of epoxy will cover at least two joints. I will do some more math and test the theory next week. Plus, I need a lot more rubber gloves as well.

Cheers

P.S. 7.00pm Just checked the fibreglass and the epoxy resin is going off nicely.

[Leo.G]

I learnt a long time ago some of the boating supplies and spa places (manufacturers) have the best prices on glass and resin. I guess they are buying it in bulk and pass the savings along. It's coming along very nicely!
As for lifting, while as you say your son and yourself can comfortably lift it if you still have to get something underneath it can be a pain. Do you know anyone with a Ute with a hyab?
A lifting eye on the top of the dome and it's up with a few pumps of a handle, that or make a tripod with some 4x2 timbers or steel pipe if you weld and use a pulley system to lift it. That would depend on how high it has to go, I'd probably shove a flag pole in the ground, lol.

I'm somewhat of a lazy mongrel so I always look for the easy option.

[anthony2302749]

Not a lot of boating supplies in my area:lol:. As for my backyard no vehicle access so no Hyab, so muscle power all the way. I will come up with the best solution to the problem. Only need to move it about 10m and up one level of about 0.4m and then lever the dome up onto the observatory, so I have a few ideas.

Cheers

[anthony2302749]

Hi all

After a lovely weekend away touring the silo art with my wife it now back to work on the observatory project.

Last week I did two seams, and it was a bit of a mess as I didn't have the correct tools. This time around I used a 100mm roller with a 5mm Nap roller to apply the resin to each side of the seams then laid the fiberglass over and the applied more resin to full wet the fiberglass. Then roller out the bubbles with a Fibreglass Compression Roller. I found that 200mL of resin was the right amount to cover three seams, only mixed up three batches.

No mess no fuss.

With this method I quickly covered 10 seams. Only have two larger seams to do.

Cheers

[anthony2302749]

So, over the last couple of days, I have been Fiberglassing the dome, this task is now complete. Today, I have installed the track for the shutter to slide along. Task was simplified by using the yellow tongue strips, 5 on each side.

The process was to place a strip of 1.5mm metal front to back for the rollers to run along. This was affixed to the back of the dome, then a stack of 5 strips of yellow tongue which were also affixed to the back of the dome. All were stretched across the dome and clamped and aligned with the shutter opening then affixed to the dome, repeat for the other side.

While not finished it seems to work quiet well. Tomorrow will be adding the rollers on to the shutter frame and then aluminium flat bar to cap of the track.

Cheers

[LonelySpoon]

Hi Anthony,

I used the Baetson design for my second observatory, before my Lonely spoon design.

Good luck with it.

If ever there was the epitome of "You can never have enough clamps" it is laying out the ribs & rings of a dome!

Feel free to visit https://homemadeplans5.wixsite.com/lsobservatory and use any ideas there for automation

Cheers,

Neville
LSO

[Leo.G]

That's looking amazing Anthony!

[anthony2302749]

:thumbsup:

[anthony2302749]

:thumbsup:

[anthony2302749]

Today's job was putting together the rollers for the shutter. I had previously cut out and assembled two plywood arc that matched the radii of the dome opening. I then drilled an attached ten 20mm rollers to each one, then attached them to the shutter frame using aluminium flat bar; this is only a temporary, have a nicer solution which I will implement in the coming days

Put the whole unit on the dome and with great relief the shutter rolled smoothly along the tracks without an issue. Very happy with the result so far.

Cheers

[Leo.G]

That's a very impressive build Anthony!
Here's a weird question, did you waste a lot of ply doing the large radius bends?
It's stopped me doing certain builds in the past, knowing I'd only get a few large radius bends out of each sheet and marine grade ply being somewhat expensive.
I have resorted to doing stacks of thin strips bent and glued for smaller jobs, nothing like a dome though. That I haven't tried building and wouldn't have a suitable place (or room, or area unobstructed by neighbours trees) in the back yard to put one.
One day I'll win lotto and buy a property where I can have a dome. I'll probably drop dead before that happens.
Though if I were to win I'd probably be too busy playing with expensive Italian motorbikes.........

[anthony2302749]

Hi Leo

There is minimal loss of plywood when cutting the radius bends. I used a 6.4mm router tip for the cutting as recommended, so possible loss 12.8mm in saw dust. After the initial cut, the scrap plywood between each radius would be about 15mm at its thickest. On a good setup you could utilise say 80% to 90% (ballpark figure) of the plywood as usable timber.

Cheers

[anthony2302749]

Past couple of days I have rework the Shutter and the track that the shutter rolls along. The shutter I replaced the aluminium for plywood block to affix the roller to the shutter frame, a workable solution, probably still need to tweak it a bit.

As for the tracks I ditched the colour bond strip for aluminium 25mm flat bar. After returning two pieces of 25mm by 3m aluminium flat bar to Bunnings for a refund of $28. I then when to Action Aluminium and picked up four pieces of 25mm by 4m aluminium flat bar for $30. Note, don't skimp.

Method used to create the tracks was to layer up the aluminium and yellow tongue and gluing them into place with Gorilla Glue ensuring everything was square and aligned correctly. Once dry screwed into place.

End result is the shutter now roll smoothly over the dome.

Cheers

[Leo.G]

You'd have to be extremely happy with your results Anthony, the dome looks amazing and it's easy to see how much work you've put into it.

Bunnings are thieves when it comes to steel and aluminium. I can buy 6 metre lengths (or 6.5M) from a steel supplier in Bathurst for less than a 1 metre length of the same thing from Bunnings, same with steel.
Bugger, I drove straight past the other day taking my son to an ENT in Orange and never thought to grab some stuff I needed. I have to take my son to Bathurst for an MRI next Monday, I better write a list.
I don't like driving (it's a migraine thing) and while Bathurst is only 45 minutes away I seldom go there.

[anthony2302749]

Been a couple of busied days on the observatory build. This post is about the construction of the bottom shutter. Fairly straight forward job.

[anthony2302749]

I have made some more improvement to the Main Shutter, one being the roller bearings. I was not happy with them affixed to the timber, so I remounted them on right angle aluminium and then attached them to the shutter frame. If I need to replace one, it just makes the job easier. Also need to fix the spacing between the out-roller frame and the inner frame due to the remounting of the rollers.

Final task was to cover the Shutter frame with 3mm plywood. This was done with the Shutter frame in place and glued, covered with ply, stapled into position. Only task left is the cleaning up overhanging plywood, fill in the holes, sand and fiberglass the edges for waterproofing.

How well does it work, very well, Happy with the results.

So, the dome as a whole is almost complete.

Cheers

[alan meehan]

What a great journey ANTHONY you are a great craftsman good luck on your retirement enjoy

[anthony2302749]

:thumbsup:

[anthony2302749]

Since my last post I have completed assembly of the shutter track. This required the addition of the top aluminium strip which was aligned and screwed to the yellow tongue. Some minor teething problems with binding caused by the aluminium strip rubbing against the support blocks of the shutter rollers, this was correctly readily easy by trimming the support blocks by 5mm.

Also position and affixed the bottom shutter.

The Dome is 90% complete.

cheers

[anthony2302749]

So today was the beginning of the observatory build which is going to be a square structure. The process that I have adopted is to construct the roof/Dome support structure first. This will make the process easier with mounting the support ring and rollers prior to installation. Who wants to be up and down a ladder all day.

Also have completed the assembly of 16 rollers for the dome to run on.

Cheers

[Leo.G]

That's going to end up being an amazing build Anthony. The attention to detail is a credit to your skills.
I'm sure you're going to spend many great nights in the dome once completed.
Silly question, what coating are you going to finish it in?

[LonelySpoon]

Bunnings has a preparation undercoat that will stick to epoxy. It works well. You probably need to find someone in the paint dept without acne to find it- I had to.

Going to look great!

Neville
LSO

[anthony2302749]

:thumbsup:

[anthony2302749]

Progress to date. Finished off the frame for the roof/dome support. As I only need to cover the corners, I decided to keep it simple and go for a flat roof design, using 17mm CD Plywood which will be waterproofed.

The decision to go with a flat roof was based more or less on the need to keep the structure within the 3m council rule and the over complicated carpentry to angle the corners. So, it was stick with the KISS principle.

Also assembled the base ring which will be used to mount the roller bearings.

All up, looking the way I have planned in my head.

Cheers

[Boozlefoot]

https://dandenongcastors.com.au/collections/conveyor-rollers/products/ball-transfer-unit

[anthony2302749]

Did consider that style of caster but from my research they don’t work well particularly with metal on wood, If the wood is soft it will cut in. Best solution would be to attach a metal base to the dome ring for it to work properly which I did consider but found it to be somewhat difficult and time consuming. I have made my on roller that will do the job.

Thanks for your advice.

Cheers.

[Leo.G]

Those multi-direction rollers definitely wouldn't be good rotating on a timber base as you've already decided, the wider units you've made up will be much better. Even were you to put a steel ring the roller would still eventually groove the steel depending on the thickness of the sheet and working with thick sheet steel is not easy, not light, far from simple to cut and would add significant cost.

Overall every bit of your construction is looking amazing. Did you work with timber as a trade/job or just an interest?

[LonelySpoon]

I haven't found anything better than 1" steel tube and trucks made with 4 skateboard wheels. Holds up my 3m dome no probs, and it rotates with a hand push or wiper motor.

Neville
LSO

[LonelySpoon]

Leo,
It was round tube bent into half circles at a small engineering place for about $160.

The trucks were easy to make, although the bearings in this image were replaced with better ones later

[LonelySpoon]

Oh, and I know I can't count. That's 4 bearings for a straight roller and THREE for a circular one...
Neville,
LSO

[anthony2302749]

This weekend I finished off the observatory roof and installed the rollers and alignment wheels.

[Leo.G]

Looking good Anthony, have you tried your custom rollers out yet?


Sorry, I deleted my former messages, I wasn't trying to hijack the thread in any way, just curious about the steel ring and roller set up mentioned for a future project (an automatic adjustable step ladder set up designed and modelled by my son to revolve around a pier for use with a Newtonian, adjustable step height with electronic control).

[LonelySpoon]

Anthony,

I love the way you've recessed the roller mounts into the ring. Good thinking!

That will really minimise the gap and size of the skirt needed.

Neville

LSO

[anthony2302749]

:thumbsup:

[anthony2302749]

:thumbsup:

[anthony2302749]

This weekend was devoted to the construction of the observatory building which everything will sit upon. Started with digging in the foundation for the floor frame, had made a bit of a start on it last weekend. Total of eight holes dug out, a bag of concrete for each, levelled. I then used TuffBlock 300 x 300 x 90mm Instant Foundation System Deck Support for the 100mmx100mm timber foundation. Of course, the old observatory had to go before I could do any further work, pretty quick job taking it down.

Did the out frame first, levelled and squared and then filled it the remained of the joists. That was Saturday's job. Sunday saw the wall frames go up and the floor loosely fitted.

Other than making one small mathematical error the construction of the observatory building was quick and easy. The one thing I was concern with was the ease to which I could climb in an out of the observatory. Turns out not a problem at all.

Cheers

[AstroViking]

It's coming along really well, Anthony.

How tall are you making the walls? They don't look more than 4 feet tall.

Cheers,
V.

[anthony2302749]

Hi Steve

4 foot 4 inch to be precise. Due to council bylaw I can’t exceed 3m and my back yard isn’t flat. I averaged the lay of the land out and add that into the calculation along with the dome height, roof height to come to suitable wall height. Did make an error of 90mm at the start which I quickly corrected. So cross fingers I have got the observatory height under 3m and the council will not annoy me about it.

This afternoon I did go back to the original plan by Charles Baetsen which I downloaded from the internet, his plan had wall height of 4 feet. Also check the dimensions for 2.3m Sirius Observatory, its wall height is 5 feet. So I sit between the two.

Cheers

[anthony2302749]

Afternoon All

So, this week saw the installation of the roof/dome support and the floor is now cut in and nailed down. One of the things that I did to make cable management a bit easier was to install a sub floor for the routing of any power or device which may be connected to the telescope. All made with repurposed timber from the old roll of box observatory.

Also, fiberglass the shutter for add water protection and slapped a bit of paint on the inside before installation for the last time.

Cheers

[anthony2302749]

First project for this weekend was to get the dome up on to the observatory with the help of my son. While the dome is bulky it is not overly heavy which meant it was a good two-man lift in army vernacular.

I used a set of dolly boards to manoeuvre the dome from the pergola up on the paving then up on to the lawn. From there we man handle it on to the lifting frame and slowly jacked it up until we got it in a manageable position where we could slide it onto the observatory. As Scott Cam would say, "Job done".

Once up I discovered couple problems which will need to be rectified. They are the rollers, found that the bearings moved within the aluminium tube so made some modification to fix that issue. All so the shrink tube on some need hitting with the heat gun again.

Other more annoying problem is that the dome base doesn't sit flush the observatory. The problem comes down to a carpentry error on my behalf, my levels are not level. I have a fix in mine which I will discuss next weekend.

So, I am happy the dome is up, it is waterproof, and the project is coming together nicely even with a SNAFU.

Cheers

[anthony2302749]

Second project for this weekend was to clad the outside of the observatory. Got most of it done until I had to call it quits due to the rain. The cladding itself is just fence paling that I recycled from the previous observatory. As Bob the Build puts it Reuse, Reduce, Recycle. I will be painting the exterior later to give the cladding a nicer appeal, haven't decided on a paint colour yet.

Cheers

[LonelySpoon]

Looking really good Anthony!
Have you given any thought to mechanisation/automation?

Neville
LSO

[anthony2302749]

Hi Neville

I have explored some options for motorisation of the dome. I will probably start with a wind wiper motor to start with. Then work towards a more advance system using computer control. But first need to do some adjustments to the dome to get it to roll smoothly after my little Snafu. This will involve cutting some of the ribs where they are affixed to the ring and packing them out once the dome ring fit flush to the observatory. The saving grace is that the joins were glued and tack into position, so easy to cut with the right tool. Should have the modification completed by the end of the weekend. Photos and explanations to follow.

Cheers Anthony.

[Leo.G]

It's looking great Anthony!
Windscreen wiper motors seem to be the go, high torque units and low speed, plus, easy to get and I'd guess wreckers wouldn't want an arm and a leg for one?.
I used one out of a Ford Consul back in the early 70's to power a small project I built.


Have you looked into tracks/gears yet?
I noticed a thread by a fellow (G_Day - Matthew) who had trouble with the spacing and gearing on his Sirius dome (from memory) recently. It would be a good idea to ask for options.
I wouldn't go for nylon gearing because it can strip easily, steel can rust. It would be somewhat of a tricky compromise I suspect, possibly a driven roller system as Neville had mentioned using roller skate wheels (wait, skateboard wheels, I don't remember) running on a steel ring he had rolled. It would be easy to make one set (or two sets) of the wheels driven to provide the guiding/rotation.
Now you've got me thinking about how I would go about it if I had a dome, something I don't see in my immediate future.



Good luck with it!

[LonelySpoon]

Two new wiper motors cost about $50 each off Ebay a couple of years ago.

Although one seems quite happy pushing my 3m dome around, I put the second one on the opposite side.

This did two things: it smoothed out the rotation by cutting out any tooth jumps (on my giant planetary gear), and it served to equalise the sideways pressure on the ring.

They also gave two potential maximum speeds. I chose the fastest and put a speed controller from Jaycar in the line

Cheers,

Neville
LSO

[anthony2302749]

So, I made mess of the dome ring by stuffing the levels which meant the dome did not sit flush with the top of the observatory. To correct the problem, I had to cut several of the dome ribs to get the dome ring to sit flush. Job was made easy with Ryobi 18V ONE+ Multi Tool fitted with a Wood and Metal Plunge Cut Blade and a small jimmy bar. Once I got the ring free of the ribs and plywood covering, I clamped the dome ring into position and packed out each rib the required amount. This task was followed by affixing 20mm x 8mm trim between each rib to just tied up the inside of the dome a bit. Proof will be in the pudding next weekend.

NOTE: - To anyone who may be contemplating a similar project I would recommend that you build a flat surface out of two sheets 18mm ply and structure timber. This way everything will be level, something I should have done if I was not a tight ass. Plus, I should have trussed the levelness of the decking. Anyway, lesson learnt.

Cheers

[Leo.G]

Considering you've done the entire build yourself with what you had, there was always the possibility of minor teething problems.
Aren't these battery powered multi-tools amazing in a pinch, renovators or whatever the call them?
I have a pneumatic one I've never used and a battery one I grab on short notice.
Overall Anthony you have made one outstanding obs' by yourself and you should be both proud of the end results and your own work. It looks amazing!

[anthony2302749]

Been a while since my last update. Between, high winds, rain, funeral and wedding anniversary etc I finally got the dome sorted.

As I stated in my previous post, I made mess of the dome ring by stuffing the levels which meant the dome did not sit flush with the top of the observatory. After stuffing around trying to resolve the problem, I decide the best course of action was to redo the levels from scratch. So, working through the problem I realised a laser level would be the way to go. I ended up purchasing a Ozito 360-degree line laser from Bunnings for $139. Important point, should have purchase the unit at the start of the project would have save a lot of time and material. Oh well live and learn.

So, I level the top of the observatory, built a new ring for the dome, cut out the old dome ring inserted the new one, checking the level as I went. The end result is that the top of the observatory sits flush with the base of the dome. And with the rollers installed the dome now rotates smoothly.

Cheers

[anthony2302749]

Since I have the dome sorted, I have waterproofed the roof and then install the skirt around the base of the dome. For that job I use 90mm x 11mm pine trim. Manage to get one coat of painting completed before it rained, yeah.

[LonelySpoon]

I think this is probably the neatest installation I have ever seen, Anthony, beautifully done.

Keep on top of the painting. I look like having to replace a panel because water got into a hairline crack, froze, got bigger, etc while I was crook this last year.


Neville
LSO

[strongmanmike]

I agree with Neville, a quintessential backyard domed observatory that, awesome....with veggies at the door to boot! :thumbsup:

Mike

[anthony2302749]

While waiting for the rain to pass so I could do another coat of paint on the dome I decided it would be a goodtime to purchase and install a door. $80 bucks later the observatory is now up to lock up stage.

You may notice a white box attached to the wall left of the entrance, this is a caravan inlet power point. I have an external power point at the back of the house so all I need to do is use a 10m power cord to run power to the observatory. A neat solution.

Cheers

[anthony2302749]

:thumbsup:

[anthony2302749]

:thumbsup:

[TrevorW]

Nice job, is that a solid core door ???

[anthony2302749]

No, just a cheap honeycomb core construction. Had to cut it down to about 1370mm from original 2040mm to fit. Not perfect but workable.

Cheers

[anthony2302749]

This weekend the following was completed on the observatory, electrical work, insulation, plasterboard and additional waterproofing measure to the roof.

Electrical work involved installing 6-power point and a light circuit. For the 240v I have used a caravan inlet adapter mounted to the exterior of the observatory. From here cable was run to connect 5 x double power point and one single power point. The last power point would have been a double, but I came up short and it was the only one left in my electrical junk box. I will be swapping it out later.

For the light circuit, I wired up a two-way switch using two 2-gang switches. One gang for red the other for white. This arrangement allows me to switch the lights on and off from either side of the telescope. As for the lights these are your stock standard trailer lights, one red the other white. As the lights are 12volts the whole system is powered by a 12v 2Amp DC power supply which is tucked away under the floor in a purpose made cable management conduit and is connected to a power point which I installed specially.

In practise the whole system works extremely well. As mentioned, I have an exterior power point installed on the back of the house so it just a simple matter of running an extension cord to the observatory and plugging it in to give power to the observatory. The lighting works well giving adequate illumination both in red and white light.

Saturday saw most of the insulation, (I got my hands on to two free bags of insulation, I included them in the build, should be of benefit), plasterboard and power points installed and Sunday the remaining wall was completed.

Still a bit more work need to finish the interior of the observatory e.g putting in some trim to tied up the corner's ceilings, plastering, painting and installed corner work benches and a pully system to open and close the shutter.

During past rain events I have notice water seeping back into the observatory via the roof edging. e.g. water runs off of the edge of the roof, but a small amount trickles back on the underside and makes its way into the observatory. To stop this from happening again I added a 20mm skirt and waterproofed with the same waterproof base as the roof. Proof will be in the pudding next Friday when Melbourne is expecting up to 20mm of rain.

So as the project is coming to a close, I am thinking of returning the telescope very soon as I would like to get some images of Saturn completed before it is to later.

Cheers

[Leo.G]

Again, the entire build looks amazing!

[strongmanmike]

Looks great and all sounds like good ideas, the 12V trailer light is cool :thumbsup:

Conventional wisdom usually says that the walls around the telescope are better not insulated, to allow temp equilibrium to be reached faster..? Was this your thinking or were you more interested in air conditioning the inside and preventing energy loss during this process?

Mike

[anthony2302749]

Was more my thinking, just assume that it would help in preventing to much heat buildup, Wasn’t aware of conventional wisdom. Anyway time will tell.

Thanks

[anthony2302749]

So giving some thought to Mike’s post, I have set up an indoor/outdoor thermometer to get a bit of an idea regarding how long it will take to achieve equilibrium once the observatory is open.

Currently at 8:50pm indoor temperature is 17.2 and outside temperature is 16.8, a different of 0.8. Of course this is just the first of many results and I will of course repeat the process of cooling the observatory over the next week and months see if there is a trend.

My future plan is to add a Wireless Temperature/Humidity Weather Station like this one from Jaycar. https://www.jaycar.com.au/temperature-humidity-weather-station/p/XC0412

Cheers.

[strongmanmike]

Actually, it's unlikely to be an issue, an insulated wood and gyprock wall has little thermal mass, so once you open the dome for an evening ahead, any ambient heat built up inside the observatory should dissipate pretty quickly, with low levels of continued radiation from the walls..? :thumbsup:

Brick, stone or concrete walls are probably the sort of materials worth avoiding.

Mike

[LonelySpoon]

Lonely Spoon Obs has 50mm thick foam insulated walls. When open, the dome room quickly achieves ambient temperature as it just doesn't heat up much.
On a hot (35+) summer day the inside is around 25 degrees when I go in.

In winter the dome room can be only 4-5 degrees but the control room will be around 12 with me in it. I've considered gifting myself a small heater.

Nothing wrong with insulated walls IMHO.

Cheers,

Neville
LSO

[anthony2302749]

So, the telescope has been returned on Tuesday with the help of my son and the walls were plastered yesterday. A light sand and then on to painting and installing corner workstations. Plan to fully cover telescope before commencing any sanding or painting if you were worried.

Thanks for the comments in regard to the insulation. The temperature inside and out has been relatively consistent. The inside temperature has been one or two degrees lower than the outside. Got a 30-degree day coming up so should see some interesting results.

As for weatherproofing the observatory stood up well to the 20 plus mm of rain here in Melbourne with only two minor leaks detected.

Cheers

[strongmanmike]

Great to hear Anthony and I'm sure you are right re the walls :thumbsup: Like many others I am sure, I've enjoyed following your build, it's a beauty. Watching others construct their dreams is quite cathartic and satisfying :thumbsup: your inside shots do remind me of my first observatory build (https://pbase.com/strongmanmike2002/observatory_construction&page=all) 20 years ago, including the scope and regardless of my current improved version, I do miss many aspects of that first build...(including my physique :sadeyes:) so thanks for the show :thumbsup:

Mike

[anthony2302749]

Just a quick post, while the observatory is not full fitted out, I decide/wanted to test the scope out and at least get a practise shoot in of Saturn.

Powered up the telescope and left it tracking while I tried to spot Comet Tsuchinshan-ATLAS to no avail. On return notice the telescope was tracking in the wrong direction, forgot to enter site after factory reset. After a GPS fix it was all good. Tick off the GPS works inside the dome.

Did a couple of image runs on Saturn with laptop on the floor and happy with the results.

Cheers

[anthony2302749]

So, over the past week or so I have painted the interior of the observatory and installed a work bench. It is somewhat finished, and I am now using it for imaging, mainly Saturn. Only have about a half dozen tasks to be ticked off for the Observatory is truly finish which I will work towards over the coming months.

So, what did it cost, currently I am sitting at $2559. This is not exact but very close to what I had calculated.

The important part, the dome cost around $989. The materials purchase was at least 4 sheets of 2400mm x 1200mm x 12mm CD Non-Structural Plywood for the ribs and support ring, 5 sheets of 2440mm x 1220mm x 3.6mm Hardwood Exterior. Plus, sundry items such as roller, wood glue, paint, screws etc.

Remainder of the cost was invested in constructing the building for the dome to sit on. This was made out of 90x45mm structural timber, plaster board, fence paling etc. Sundry items include power points, paint etc.

I also scrounged what I could to reduce the cost like two sheets of plaster board, paint, electrical cable, screws etc.

So, for those who have ambition to construct their own observatory you now have an idea of cost. Mine you, if you need to purchase power tools such as a router this will add to overall cost.

Cheers
Anthony

[LonelySpoon]

Again, looking great, Anthony!

Your figures match closely with mine, at around $2500 for all the wood related part of the set-up, not counting concrete, etc.
Add $4k to mine for the insulated metal 6mx3mx2m shed to sit it on, call it $7k

WAY less than buying a commercial dome (less than the delivery for some).

You have now joined the dome club, envied by many, scoffed at as 'unnecessarily complicated' by others!

Cheers,

Neville,
LSO

[Leo.G]

That's an amazing build for the outlay Anthony. I couldn't imagine someone quoting me to build identical but I'd imagine it would be a heck of a lot more (times 5 plus some I'm betting).
Happy hunting!