Green light for observatory

[chouet]

It's exactly a year since I got my first scope, and I'm starting to make good progress with astrophotography. Adding a guidescope, though, has tipped the balance for wanting a more permanent setup.

My wife wasn't at all keen on the idea of another structure in the garden (2 sheds already), until I knocked up a few ideas in Google Sketchup - see below.

I liked the idea of building a roll off roof shed from scratch, but Libby didn't like the idea of a third shed. She has, surprisingly, given the green light for a dome, as long as I add a few pot plants around it! I'm leaning towards the Skyshed Pod, as it comes in a range of colours and its height doesn't require planning permission at the distance it would be from the fence.

We cancelled what threatened to be a wet week at Kelling Heath to start work on the deck and pier. So far, we've got 12 concrete footings in for the deck and a metre square block for the pier (isolated from the deck). All the wood's cut and ready to screw together. Between us, we moved a skip full of turf and clay and mixed over a tonne of concrete by hand (actually Libby did the lion's share of the mixing!).

I have a few questions:

What is the best way to deck around the pier? Presumably, leave a small gap to isolate it, and then use soft flooring inside the dome (if I go that route) to seal it from creepy crawlies?

Will I need a dehumidifier? I'm planning what power I need to allow for.

Should I route all 12v to the shed, or put a transformer in the observatory?

Thanks in advance

Nick

p.s. Sketchup pics below - garden faces North

[pmlogg]

Nick

I've not long finished a similar project, but with a Pulsar dome - a demo model became available at an attractive price; otherwise at that time there would have been a bit of a wait for a SkyPod. Reference your questions:

(What is the best way to deck around the pier? Presumably, leave a small gap to isolate it, and then use soft flooring inside the dome (if I go that route) to seal it from creepy crawlies?)

I used standard decking. I calculated out the length of the joists and decking panels using a spreadsheet allowing for around a 5mm gap at the walls. Once cut to overall length I laid the panels out, correctly spaced on the patio, and used a long string as a compass to draw the curves. After cutting the curves I preserved the cuts and treated the decking boards. Once the dome was in place I built the floor leaving some panels out and drilling holes in the joists for underfloor cabling. One of the floor boards is double hinged so that I can easily get at the cables. I had to adjust the lengths of some joists as the wall diameter was slightly less than expected and also around the doorway. Now in place I think it looks pretty good and even the hinged board feels solid to walk on. The wood floor feels a lot more comfortable to stand on than freezing cold concrete/stone.

I'd decided to mount some of the waterproof boxes for the electrics etc. directly onto the pier (one of the problems with a prefab round building). That plan had to change as the welder couldn't get square stock of the right size so used tubular instead (it's steel, but powder coated to protect against rust). So I used scrap plywood to box in the pier, and also to make an octagonal shelf/table top all around to lay things on. Neither the boxing nor the table top touch the pier. The pier surround sits on a base of scrap decking, screwed to the floor and the cables come up inside it, out an access hole to the electrical boxes. In the end I'm happier with that solution too, as it gave more room for the boxes, a useful table surface and again all with a warmer feeling than metal. I have more boxes attached to a plywood structure attached to the join between 2 of the wall sections - I'm not sure whether that is a runner in a SkyPod, but that design has the option of side pods so I suppose electrical boxes could be fitted within one of them somehow.

I didn't seal inside against bugs, but used sealant at the joint between dome walls and the base (a stone circle in my case). So far I've not seen any insects, but the observatory isn't airtight so they can get in at the gap between the wall and the dome anyway.

(Will I need a dehumidifier? I'm planning what power I need to allow for.)

I took advice from this site and bought a dehumidifier. It is connected to a timer switch, which has an internal battery that means programming isn't lost in a power out. It has a pipe leading outside which means it doesn't come to a halt due to a full water container. I had to raise it up on blocks to improve the flow out as once it did fill the container and stop. One thing I hadn't anticipated was that the one I bought needs a cool down period before it switches off - a timer doesn't allow that; it just switches the power off.

(Should I route all 12v to the shed, or put a transformer in the observatory?)

I had an electrician connect 240V circuits (one power, one light) into the observatory. There really wasn't any other choice, not least as the dehumidifier needed 240V. That meant armoured cable going sub-surface into the house and an extra consumer unit inside. I tried to follow the advice of others and have around 7 double sockets. For the 12V I have 2 transformers. One 13.8V for the mount only and another 12V for the dew straps etc.; also individual power adapters for the components that need them. All the electrics are in IP rated boxes, kept closed when the observatory is not in use.

I hope this helps. I'm certainly enjoying the speed of not having much to set up each time, and more importantly not having to put it all away at the end of the session. Being able to just close the room when the clouds come over, or rain threatens is great too.

Best of luck with the build.

[darditti]

Well-done. The plans look attractive. I've not heard of anyone persuading their spouse by this method before!

Question 1: Yes, a deck with some kind of soft flooring is a good idea, keeps you warm and protects equipment that falls. Make it with boards screwed to joists that are at least 3" thick and no further apart than 18". The joists need to be kept off the ground by bricks or concrete, but an observatory like this doesn't need major foundations.

Question 2: Conventional dehumidifiers fail in observatories as they don't work when the temperature gets to around freezing, which is exactly when they are most needed. There is a type I saw advertised in Astronomy Now that does work at all temperatures, but I don't know exactly what it is. Having tried various dehumidifiers in the past and found them very unreliable, I have now given up on them and instead leave the dew heaters on all the time, powered by a transformer. This is effective at keeping the observatory quite dry and slightly warm.

Question 3: You need mains to the shed. You have to get it done by a professional electrician, or, if you do it yourself, it has to be certified by the planning authority and you have to know the regulations. Don't mess about with batteries, or try to route 12v to the shed, it won't work, power losses will be too great.

I hope this is helpful. I'll take this opportunity to plug my book that covers all this stuff: Setting-up a Small Observatory.

Best of luck,

David

[ampleamp]

Hi Nick, I put my obs on decking. Can't give you a link from here but it was titled "it starts with a hole" and was from around the beginning of august last year in this section.

I just cut the decking roughly to fit around the pier as there will be your dome floor covering the gap anyway. I used expanding foam to seal the gap around the pier at decking level which works well (there is no pier contact with the obs floor). Hopefully this should be visible from the photos.

re power, if you have an obs, you will want a permanent 240v supply rather than a 12v, makes everything so much easier and if you get a dehumidifier you will need it anyway. (i have a dehumidifier now and would def recommend using one) There are loads of threads on electric supply and dehumidifiers to peruse. Electric is fairly straightforwards but get a sparky to sign it off. I didn't bother with cat5 cables as network connection comes through the electric as well.

HTH,

ampleamp

[michaelmorris]

My only comment would be to carefully sit down and work out the maximum number of power sockets you can sensibly envisage ever needing - then double it!

In my observatory I have power sockets for:

Computer

Monitor

Stereo

white light

red light

spot light

mount

12v transformer

powered USB hub

Scope cooling fan

heater

+ 3 spare sockets to cover such things as laptop, portable hard drive, cooling fan (for me, not the scope), vacuum cleaner (for the carpet!) etc.

[chouet]

Thanks for the feedback - very helpful!

David, I bought and read your book a couple of weeks ago. Really helpful and gave me the confidence to get the project started.

[darditti]

That's nice to know Nick. I'm sure it will be a great success. And thanks for making me aware of this Google Sketchup tool. Very useful.

David

[chouet]

Update: Pod on order, and the deck/pier is nearly finished - the centre third around the pier is removeable. I still need to get power sorted out, which should be straightforward as I have an RCD fusebox in the shed.

I'm not sure whether to go directly to the fusebox, or use an extension and socket.

I've got enough armoured cable left from having the shed wired up to use that. Would it contravene part P to run armoured cable with a junction box at the shed end (and 13amp plug into a socket/RCD), and a waterproof junction box at the deck end? I'm not sure of the junction boxes would then make it a fixed installation.

Pics so far (my wife and I mixed over a tonne of concrete for the pier base and deck base - all by hand. Never doing that again!!):

[Horus]

Looking good, when does the Pod arrive ?

[Dave Smith]

Hi Nick

Sorry I missed this thread. I have a SkyShed Pod in my back garden which came last year.

http://stargazerslounge.com/astro-lounge/108274-my-new-skyshed-pod.html

The dehumidifier I use is as follows and I have it set on a low setting and 60%. I have had no problems with any condensation all winter.

ELA DD822 Dehumidifier & Laundry Drier | Laundry Driers | Dehumidifiers

There are other companies that do anti-fatigue flooring but I used machinemart. Two packs was sufficient.

Clarke Anti Fatigue Foam Floor Tiles - Pack Of 6 - Machine Mart

I am in Maldon, Essex which isn't that far from you. If you would like to come and have a look at my set-up you are more than welcome and/or if you have any questions feel free to ask.

Do listen to Micheal's advice re sockets. I had 4 put in but am already using an extension socket strip.

Having the observatory was one of the best decisions I've made. You will enjoy it and do more astronomy.

Dave

[chouet]

At the last update, the Pods heading for the UK were waiting to be shipped by sea.

Dave, reading your Pod post was what swung it for me - Libby (my wife) insisted on the same grey combo. I'd love to have a look at your setup - I'll send you a PM.

[iamzoso60]

I have a Pod on order and have been told that they are on the way also. Mine is on order from Altair....same for you?

Here's my progress so far.

[chouet]

LOL - my wife is threatening to put table and chairs on my deck too.

Yes, on order from Altair.

[iamzoso60]

The chairs have got to go and the dog will not be pleased either when the Pod arrives, as he loves sitting on the deck, watching the birds! LOL

[Dangerous-Dave]

Hi Nick

Sorry I missed this thread. I have a SkyShed Pod in my back garden which came last year.

http://stargazerslounge.com/astro-lounge/108274-my-new-skyshed-pod.html

The dehumidifier I use is as follows and I have it set on a low setting and 60%. I have had no problems with any condensation all winter.

ELA DD822 Dehumidifier & Laundry Drier | Laundry Driers | Dehumidifiers

There are other companies that do anti-fatigue flooring but I used machinemart. Two packs was sufficient.

Clarke Anti Fatigue Foam Floor Tiles - Pack Of 6 - Machine Mart

I am in Maldon, Essex which isn't that far from you. If you would like to come and have a look at my set-up you are more than welcome and/or if you have any questions feel free to ask.

Do listen to Micheal's advice re sockets. I had 4 put in but am already using an extension socket strip.

Having the observatory was one of the best decisions I've made. You will enjoy it and do more astronomy.

Dave

Those Clarke fatigue mats are just what I need. I take it they cut easily with a Stanley knife?

What sort of adhesive did you use?

[Dave Smith]

Those Clarke fatigue mats are just what I need. I take it they cut easily with a Stanley knife?

What sort of adhesive did you use?

They certainly do cut easily with a Stanley knife. I haven't used any adhesive. There doesn't seem to be any need and just as well as I have lifted part of it a couple of times to lay more leads underneath.

Dave

[Dangerous-Dave]

They certainly do cut easily with a Stanley knife. I haven't used any adhesive. There doesn't seem to be any need and just as well as I have lifted part of it a couple of times to lay more leads underneath.

Dave

Thanks Dave, I am going to invest in a couple of packs!

[Psychobilly]

The mats are on "Special" at maplin at the moment...

[iamzoso60]

Yep £12.99 per pack. I picked 2 up earlier today.

[Dangerous-Dave]

The mats are on "Special" at maplin at the moment...

#*£@! Just bought two packs direct from Clarke's.

[Psychobilly]

Sorry Dave...

I did post in this thread and in heads up...

[Steep]

Those mats are the bees knees! I too missed the heads up about Maplins and bought from CPC. Still very good value though.

[chouet]

Dave, thank you so much for taking the time to show my family your Pod setup - I really can't wait for mine to arrive now!

On such a cloudy day, I'd never have considered getting set up and looking at the sun (therein lies the value of the obs). The view through your Vixen was fantastic.

Thanks again

Nick

[Dave Smith]

No problem. It was a pleasure meeting you and your family.

You have hit on the main pleasure of having an obs. - no cooling down time, little setting up time. If the weather is a little dodgy I will use it for observing and if reliably clear then it's imaging. The amount of astronomy I now do per unit time has considerably increased even though the weather seems to have gone the other way.

Dave

[Dangerous-Dave]

Sorry Dave...

I did post in this thread and in heads up...

No worries dude. The mats really are - as Steep says - the bees knees and worth every penny I paid for them. My dad and I tiled the pod with them on Friday and they are comfortable, hard wearing and don't need any adhesive.

Two packs are just enough, providing:

A. You don't mess up!

B. You use the most economical layout (attached)