Jovets Observatory build

[Ivor]

The top of the roof is cover tgv and has a 2nd coat of paint, as the sides walls will be lower the base of the ring I can't put them on until the roof frame is in place on top of the walls.





All 7 walls and the door are on and I've even managed to put the floor in all that is needed is a couple more coats of paint during the week, ready for next weekend.



I have to admit I'm a little nervous about the roof going on next weekend, it's the most important part of the design and I've no way of being 100% certain of there not being a issue; fingers crossed.

[Ivor]

A shot of the outside

[Carole]

Great progress Ivor.  What a great little space underneath for wildlife to shelter, what a kind gesture.   

How are you going to hold the roof on Ivor?

Carole

[Ivor]

Yes it had crossed my mind some wild life might check, however our jack russell should keep any permanent residents out. To keep the roof and wall rings aligned I'll fitting 4 right angled brackets to the bottom ring facing upwards  about 10mm away from the true position. If this doesn't work I'll look to put some casters on the brackets and moves it closer to the roof rim.

For protections against high winds I'll probably use the same clamps as Mark did.

[MarkS]

Good progress Ivor.  It's certainly coming together now.

What are the bathroom fittings on the pier?

The roof sections look fairly flat - what will prevent rain leaking through the tongue in groove?

Mark

[MarkS]

Planning to put a 12V supply on the pier to support the dew heaters and I was thinking of using a down lighter transformer like this http://www.screwfix.com/p/halolite-low-voltage-electronic-transformer-20-60va/48058. This would give me a maximum of 5A at 12V is there any reason why this is a bad idea?

Interesting idea.  It's probably OK for dew heaters.  I certainly wouldn't use it for sensitive electronics.

Mark

[Ivor]

Good progress Ivor.  It's certainly coming together now.

What are the bathroom fittings on the pier?

The roof sections look fairly flat - what will prevent rain leaking through the tongue in groove?

Mark

The sides have a 5% slope it's not so obvious from the angle of the image. I'll also use sealant in all the gaps to reduce the chance of leaks, if there are big problems it won't be hard to remove the top in sections so I can add a water barrier as well.

The bathroom fittings are for the cabling the other end is under the floor, I'm building a wooden frame and faceplate to go over the top which will have the 240V , 12V power and USB sockets on. I couldn't use standard electrical conduit as it's too small for a USB cable to go around the bends inside the pier.

[The Thing]

Planning to put a 12V supply on the pier to support the dew heaters and I was thinking of using a down lighter transformer like this http://www.screwfix.com/p/halolite-low-voltage-electronic-transformer-20-60va/48058. This would give me a maximum of 5A at 12V is there any reason why this is a bad idea?

Interesting idea.  It's probably OK for dew heaters.  I certainly wouldn't use it for sensitive electronics.

Mark

ou should plan on having a couple if you have several heaters. Get these LED lighting controls boxes off Ebay as dew heater controllers, they handle 8 amps each and are ready to mount somewhere with the down light transformers.

[Mike]

Ivor I have a box full of those dimmers if you want a few.

Mike

[Ivor]

I already have a PWM for the dew heaters however I could use one on the 12V lighting as well as having a spare. I plan to come to the Christmas quiz are you going Mike? If so for the appropriate amount of silver I would happy to take a couple of your hands.

[Ivor]

Last weekend was full of problems, the roof was put on Saturday morning and from that point onwards things general went downhill. I'd designed the the base of the roof to have a 15mm gap between the top of the walls and the bottom of the roof base, this has been proven to be too small. With the weather and having the roof resting on stilts for the last month to keep it level during the build phase the base has warped and is catching on the roof top. This problem is compounded by slight differences in the levels of the wall uprights which weren't apparent earlier; my fault again, I checked the levels of the posts across the whole width of the buildings frame where 5mm over 2.4m wouldn't show up on a level, I should have also checked against adjacent posts as well.





I've mitigate the gap problem by adding plywood padding under the bearings and by placing clamps on the areas with the most bowing it has reduced the variance in the roof base to ensure there is a sufficient gap. To keep the roof in place when it is being rotated I'd planned to put 4 rollers on the inside like below.


I knew the initial wheels were too thin but I'd hoped to iron out the kinks with these and then buy some wider ones once I'd worked out the details. Well this have proven to be a non started there doesn't appear to be an easy way to give them sufficient rigidity to push back on the roof base.




I could give them greater rigidity by securing them to the roof base and having them hang down and push against the wall ring this causes problems later on as I want to automate the roof and as these rotate they would hit any motor I placed on the wall.



This film shows you what the inside currently looks like


https://flic.kr/p/q9gWb3

If I'm honest the roof is an eyesore it doesn't work aesthetically, it's better with the cladding on (sorry no picture I finished that at 18:00 on Sunday in the rain so had to cover it up quickly so I'll add it later) and my very patient wife who has let work on this solidly for the last 10 weekends is not impressed; at least if it worked I'd have some leverage. As I was running out of time as we headed towards Christmas I've had to rush the roof, I can't do anything major now until the new year but I'd like to get the roof rotating manually so I can at least do some imaging.


Feeling deflated and frustrated so any thoughts or ideas gratefully received.

[MarkS]

I'm not surprised you feel deflated.  I kind of know the feeling - in a week's time one year ago, my own flawed design led to the loss of the whole roof in the Christmas Eve storm.  Your design is quite "adventurous" so it allows plenty of possibilities for problems.  If I understand things correctly, the way I see it is as follows:

1) You have four(?) wheels attached to the shed that the roof sits on.  It is crucial that these lie in a horizontal plane with solid support underneath each one so they cannot drop with the weight of the roof on them.
2) It is essential that the roof "ring" that sits on the wheels is flat, without any warping and supported with sufficient structure to prevent it bending under the weight of the roof.

e.g. maybe the ring should be solidly screwed to the underside of some kind of framework built of 3" x 2" like this:

++++++++++++++++++++++++++++++++++++++
+             +              +                +               +               +
   +          +  +          +  +           +  +           +  +           +
      +       +     +       +      +       +     +        +     +        +
         +    +        +    +         +    +        +     +        +     +
            + +           + +            + +           +  +           +  +
++++++++++++++++++++++++++++++++++++++

You may need to detach the roof from the ring, add the supporting structure for the ring and then attach the roof back to the supporting structure.  However, such a structure would make it feel more claustrophobic inside the observatory.  But I do think the roof ring requires extra support.

Mark