Graeme

Today was the first dry day for almost a week. I took the external cladding and the insulation off and tried plan B. I decided to cut the insulation into rectangles and fill each of the wall cavities with a double layer. It's a slow solution but the Correx boards I got will lay nice and flat, seal the walls and allow a much better feather board cladding install.

Excellent horizon view!

6 hours ago, George Gearless said:

So if I've understood you correctly, you do intend to keep the observatory heated (above dew point, that is)? 

Yes, but, the heating is only frost protection and anti condensation. Condensation only happens when ambient temperature drops below the dew point. That will happen all the time when you point your telescope up towards the stars, it's not such a problem when the roof is on. Air movement is key so I'm going to use fan heaters. If Trevor the weather forecasts really cold temperatures I'll bring my stuff indoors.

9 hours ago, Miguel1983 said:

But ballpark for a similar size and finish between €30k and €45k.

It would be a struggle for me to get the sign off for that level of expenditure!

A truly beautiful build and a pleasure to see the photos. Recessing the roof rollers is a good idea to keep the gap small. The two stage, below and above ground level pier block design gives you a huge mass. Will the total mass of concrete do away with the need for pier block isolation?

Graeme

My roll off roof observatory is still in the construction stage. (Here) The plan for environmental control is to use an Arduino and DHT11 temperature and humidity sensor to turn on fans when the temperature gets too hot and heaters for frost protection. To prevent condensation you need to keep the temperature 2 or 3 degrees above the dew point so I'm thinking of using a fan heater for that. Martin's (above) solar fan idea is good because it is fully automatic and can be installed high in the gable end of the rolling roof section. I'll probably copy that one!

What type of observatory are you planning?

Graeme

I made a start on the external cladding yesterday but I'm not happy with it! There were some rolls of roof insulation left over in my loft (the stuff that goes over the rafters) and I stapled sheets of it to the out side of the timber frame and then fixed the feather edge boards over it. The plan was to fix the feather edge with my nail gun but it didn't hold too well so I screwed them in, but I don't like to see the screw heads and they split the board at the ends, even when drilled first. So I'm contemplating taking them off again, taking off the insulation and using Correx boards instead. I can use the insulation to in fill the void behind the Correx. Then I can seal round the boards and I'll have a nice flat surface to fix the feather edge boards to. It's raining today so I have some time to think about it!

14 hours ago, ArmyAirForce said:

March 25th

On the 25th, all the arrangements were in place to collect the railway parts for the garden feature. 

My kind of garden feature! I spent the last 20 years working on the railway (Electrification) Retiring this year. Looking forward to seeing what you do with your bits!

20 hours ago, Mr H in Yorkshire said:

Mice can get through a 10mm gap. Might I suggest stuffing stainless steel wire wool down all the gaps, I had a problem with plastic water pipes getting gnawed and stuffed every hole I could find, no problem since. The material I used was for pot cleaning, be careful if you do use it, wear gloves because a single thread will slice through your fingers if pulled on.

One of the observatory build threads on here had a circle of rubber stretched over the pier and then fixed to the floor. I can't remember whose thread it was but it was a quality build.

Edit: It was @ArmyAirForce's Pinetree Observatory:

I will be copying this idea if that's ok Stephen!

4 hours ago, malc-c said:

Oh and don't do the same mistake as I did and use overflow pipe for the cables.  Use 1.5" sink waste with gentle bends rather then sharp 90 degree.  

Another good idea. I have this one covered though. I used 1.5" waste pipe with 2 x 135° bends in series at every right angle. It makes a nice sweeping bend.

Anyone fancy a Lego Moon map?

https://www.universetoday.com/160872/an-amazing-new-map-of-the-moon-in-lego/

8 hours ago, carastro said:

It's coming on well Graeme, I love the puddle of water in the tarpaulin.  Lol

Carole  

Thanks Carole

It was lashing it down on Thursday night! I'm off work this week so I'm hoping to get on with it to at least the stage of watertight. It would be a significant stage to reach because I could start using it! I haven't captured an image since last August (except for a go at Jupiter that wasn't too good) And I'm suffering serious withdrawal!

10 hours ago, malc-c said:

The build is coming along nicely... Glad my build has helped in a small way...  It's a really easy job to chisel out the mortar and replace a normal brick with an air brick.  In the course of recovering the cables that ran from the mount to the warm room I lifted the hatch and was please to see the underside was clean and dry, so they work !

Thanks Malcolm

It would probably be a good idea to put them in before the floor goes down. And an access hatch is a good idea too that I didn't think of!

OSB on the inside is all done. I put a tarpaulin on the top because rain was forecast.

Good job too!

The plan was to put some insulation in between the 2x2s and make a start on the external cladding today but there was a tsunami when I pushed the lake off the tarp! So I made a start on the roof section instead. The roof will sit on a frame the same size as the top and bottom sections, so I got that done and then had to stop and do some trigonometry to work out the angles to cut the trusses. Probably should have been doing that of an evening instead of messing about with a rain sensor and an Arduino! We're not quite at the stage for that yet. Who knew observatory roof design maths would be so much fun! I'm going for a 25° slope with the slope towards observatory rather than the gable end to maximise viewing angle when the roof is rolled off.

I bought some fixed castors this week and I'm looking for 2 x 6m lengths of angle iron for the next step. @malc-c's observatory build thread was resurrected with perfect timing to point out the need for air bricks in the base brickwork, for which I'm thankful. So I need to put a couple of those on the shopping list too.

I made a test frame out of roofing batton to get the dimensions needed by slewing it about as Rallemikken describes. I added 100mm on all sides and 1m to one side for the entrance, a desk and a cupboard.

Good luck with the build.

Regards

Graeme

Sorry to hear a move has been imposed on you. 

I'm new to your Observatory Build thread and I have greatly enjoyed reading through it. My build is at the stage of realising I've omitted to put air bricks in the base section. So your thread resurrection has come at the right time for me!

I look forward to your next build thread.

All the best for the future.

Regards

Graeme

First fix walls are done. I've been cutting up noggins all day. I started a bit early so didn't want to annoy the neighbours with the electric saw. Today was just 2" x 2"s and I have a new hand saw so I've been using that all day. I had forgotten what a joy it is to use a sharp saw! This observatory now officially has my blood in it! Next step is to get some of the OSB internal cladding in to stiffen the whole thing up before I put the roof on. I suppose it might be good to finish the walls completely before I start on the roof.

I'm glad this thread was resurrected @Hals Your observatory looks like a good solid build. It was a good read! 

My only comment would be that two more diagonal braces on the end roll off support section, at right angles to the two you have, to prevent sideways movement might be a good idea.

Regards

Graeme

That corner was made for an observatory!

I look forward to watching your build progress.

+1 on Francis' comment.

Regards

Graeme

2 hours ago, gaz81 said:

Looking good.   Looking forward to see the roof. 

Cheers Gaz

Me too!

5 minutes ago, Swoop1 said:

Recessing will give you a tad more room and sometimes a tad makes all the difference.

Good point. And there's only a narrow 12" gap on the fence side!

Starting to look like some sort of building now! Uprights are in, top section is on. 

Next step is to fix in some 2"x2"s for timber cladding on the outside and OSB sheets on the inside. Not sure whether to recess the external cladding to expose the corner posts as a bit of a feature or to do the cladding over the corner posts to hide them. I'm leaning towards the former. It might be wise to do the floor first though.

4 hours ago, Lumos said:

Looking at your OTA, Graeme, I think that I have found the source of your lack of sharpness at the edge of your SCT

It's my 18th century 2" wooden refractor! 

The rain soon stopped so I put a 12V and a USB into the mount and slewed my first pier mounted slew! With an 1800mm wall height I can see down to 15° which is lower than I need to go, so that's good. With the mount parked at 180° az 0° alt I get 50mm clearance to the roof section. It was designed to be 100mm but I haven't cut the M16 stud back yet. I'll get the disc cutter out tomorrow. My park coordinates point the telescope to where I'm hoping to put the flat frame light box .

So I retired to the greenhouse and put some seeds in trays instead!

I finished the top section this morning so the next job is to put the mount on the pier to check the wall height. But after I had put the mount on  it started to rain so I had to cover it up again.