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the yesyes observatory - the build


yesyes

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I started wiring the electrics this weekend.

On Saturday I wired up the pier. The pull rope I left in the pipe didn't want to move. it must have got glued at one of the joins. So I bought one of these nylon ones and pushed that through. Very easy. I looped back on itself and pulled the other side back in with the cables. This will make it easier to pull 2 USB cables through later.

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Then on Sunday I pulled a lot of cables

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Looking good.

You know once this is finished you'll be lost for something to do.

My wife thinks otherwise. She can't wait for me to have time to finally do something.

I think she feels a bit neglected... ;)

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Chris,

One suggestion.  Replace the power socket on the pier with a waterproof one.  Even in an observatory, due forms on everything after a long session, especially in September - December months and you really want to be safe rather than sorry.  The alternative would be to house a regulated 13.8v PSU in the warm room and run low voltage to the mount

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Chris,

One suggestion.  Replace the power socket on the pier with a waterproof one.  Even in an observatory, due forms on everything after a long session, especially in September - December months and you really want to be safe rather than sorry.  The alternative would be to house a regulated 13.8v PSU in the warm room and run low voltage to the mount

My power supplies are in the warm room.  I do have a double socket in the scope room but it's only for occasional use - not at night when imaging.  Dew is definitely a big problem and there have been times when everything has been dripping with water.  I do use a control box containing an Arduino for focussing but that generates enough heat to prevent dew forming.  The mount and cameras also produce enough heat to keep the dew away.

Actually, this is a good reminder the double socket in my scope room is just a plastic one and I've been meaning to replace it with a waterproof one.  Meanwhile, I think I'll turn the power off and move it into the warm room.  Although I make a point of not touching it when it's wet with dew I really should be more safety concious.

Thank you Malcolm for the reminder :)  I know it was aimed as Chris but applies to everyone of course.

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I would probably go with waterproof type sockets just to be safe for both you and your expensive kit.places like screw fix and others have these on offer all the time and aren't stupidly expensive :) The other thing is standard sockets do become brittle very quickly when exposed to cold found this out in my garage before I had it rewired:)

Sent from my iPad using Tapatalk

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Just look for outlets marked as IP54 or higher on the moulding case and you will have no worries. Main thing to have is RCD 30mA protection to the source of the Observatory supply and if worst comes to worst the supply will disconnect instead of you getting a shock :)

The British Standard requires RCD protection to this kind of installation anyway plus Part P of the building regs requires notification to your Local Authority if the installation is fixed . Ie not an extension lead .

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There is a 30mA RCD at the house end of the cable.

Part P has changed this year and this kind of work is no longer notifyable, unless it is a new circuit. The cable was already installed when we bought the house (to power some outside lights and a pump in the now removed water feature) so it's not a new circuit. So I should be fine. ;)

Will order some waterproof sockets for the scope room. Better safe than sorry.

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I'm not sure I'm doing the right thing here.

I've been trying to get rid of that water that leaked in weeks ago. I bought a refill bag of these moisture trap crystals and put some of them in the gaps where the water doesn't want to evaporate. It seems to have some strange effect where water droplets form where there are no crystals and there was no water before.

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Chris,

One suggestion.  Replace the power socket on the pier with a waterproof one.  Even in an observatory, due forms on everything after a long session, especially in September - December months and you really want to be safe rather than sorry.  The alternative would be to house a regulated 13.8v PSU in the warm room and run low voltage to the mount

Good idea Malcolm.  I've just got one double socket on my scope room wall and went for one of those weatherproff types just to be on the safe side.

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The crystals are calcium chloride which is a massively hygroscopic salt.  They're usually used in a plastic container with a mesh lid and as they absorb water they dissolve so the droplets are probably the result of a single or a few crystals in isolation.  It's not really the right way to use them TBH.  I reckon you're likely to end up with salt staining on the floor.  If you want to use an absorbent crystal, then get some sodium polyacrylate off of eBay.  This is the stuff they put in nappies and it is capable of absorbing an insane amount of water - around 500 times its own weight.  :)

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Just remember that any type of 3 pin mains socket only retains its IP rating when it's cover is closed, I.E. with nothing attached. As soon as you open the cover and plug something in it probably falls back to a fairly low IP rating. Circular plugs are different.

Your 30mA RCD will help, bu the best course of action is to avoid damp, sons sibyl move the 230V in to the warm room.

Robin

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I'm not sure I'm doing the right thing here.

I've been trying to get rid of that water that leaked in weeks ago. I bought a refill bag of these moisture trap crystals and put some of them in the gaps where the water doesn't want to evaporate. It seems to have some strange effect where water droplets form where there are no crystals and there was no water before.

 

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Chris, have you already tried just getting some heat into the building - a small fan heater pointed towards the damp area would be good? Leave a little ventilation high up to allow warm damp air  to escape and just leave it switched on for a day or two. 

 

If you use a powered dehumidifier, the idea is to close off ventilation and extract moisture from the trapped air in the building.  If the surrounding air is very dry, it will 'suck out' moisture from damp areas to maintain equilibrium.  I guess that crystals would work in a similar way ... you just want them in a container near the damp area so they create a dry surrounding atmosphere.  A little warmth would do no harm to encourage evaporation.

 

Adrian

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I'm a little concerned with keeping a fan heater running unattended. And I don't have electricity in the obsy yet, only a 20 metre extension reel that I need to plug in in the house and keep the window on the house open to run the cable through. I have been keeping a 1500W fan heater running when I was building and pointed it at the problem area. It got better but very slowly. That OSB is like a sponge and it's hard to get that water out.

I think I'll invest in one of these tube heaters. Thanks for that suggestion. That could then even be installed permanently as my warm room heater.

I think I made it a lot worse with this salt I put there last week. It seems to have attracted the humidity from the obsy and deposited the water exactly where I wanted to get rid of it.

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The crystals are calcium chloride which is a massively hygroscopic salt.  They're usually used in a plastic container with a mesh lid and as they absorb water they dissolve so the droplets are probably the result of a single or a few crystals in isolation.  It's not really the right way to use them TBH.  I reckon you're likely to end up with salt staining on the floor.  If you want to use an absorbent crystal, then get some sodium polyacrylate off of eBay.  This is the stuff they put in nappies and it is capable of absorbing an insane amount of water - around 500 times its own weight.  :)

I'm not really worried about salt stains. The floor will be covered with carpet tiles. I just need to get that water out somehow.

I have bought 500g of that sodium polyacrylate and it arrived today. It's in powder form (not the spheres that I had seen on youtube). What's the best way to use it? Pour it directly in that gap where I want to remove the water? Or put it in a bowl close to the problem area and wait for it to soak up the humidity? Any ideas / suggestions, please?

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Chris,

I've not really followed this recent issue.  Are you sure the water is a leak or is it condensation?  Looking at some of the images there are large droplets on wood inside the studding, this suggest to me that it's condensation more so than rain ingress, but I might be wrong.

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It was a leak. When I had the tarp on rain water was running down inside the tarp (it had some holes on the top over the finished roof). That was all fine where the tarp was hanging lower than the floor, except for one place, the main front middle upright (between front door and window) where I clamped the tarp with an F-clamp. There water did not just run down the tarp but got diverted inside by the clamp. This has stopped now but the water just doesn't want to evaporate.

The droplets only formed after I put that calcium chloride salt there. The salt must have attracted the humidity.

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