the yesyes observatory - let the planning begin

[yesyes]

Now that we have, at long last, bought our own house and settled in I'm starting planning for my obsy. I have a small-ish and slightly odd-shaped space at the back of the garden that I have permission to build an obsy on. There was a rather big Ash tree in the middle of that space but that has been felled last week (time lapse video

). The stump of the tree couldn't be ground out because the access isn't wide enough for the grinding machine. The stump is about 5cm above ground and has been poisoned to prevent it from growing new branches.

This is a drawing of the space I have available with some rough measurements (not to scale!)

The obsy will house my 10" newtonian, so the scope room needs to be around 2.50 x 2.50m or more internal size.

I would prefer not to remove the walls but work around them, but removing the wall towards North is still an option.

This is my initial idea how to make the most of the available space:

I'm looking for any ideas you may have how I could make even better use of the available space.

The initial idea for the roll-off roof was to roll over the warm room roof. Another option is for the roof to roll on runners to the West.

Attached are a few photos that might show the available space a bit better than my drawing. Because of how the garden is arranged, it's quite hard to take decent images of the space. An aerial photo would be a lot better :-)

[The Sailor]

Good luck Chris

Jim

[r3i]

Looks like an interesting garden. Having an external power source so nearby is a bonus

Wishing you every success with the project and look forward to seeing how you progress.

[sologuitarist61]

Sounds like a plan Chris, especially like the idea of the roll off roof going over the warm room, also like the fact that the power is so close by. Hope it goes well (you will need to get some of the shubbery cut backa bit) then it looks like you will have good all round visibilty.

[yesyes]

Thanks!

Yes, I was very happy when I realised that there is a power source right there already. It was used to power some external lights (12Volt halogens) and the pump/filter for the (now removed) water feature. There's something wrong with it though. It's protected by an RCD in the main fuse box inside the house. As soon as I switch that on the RCD trips. Needs further investigation. I'm hoping it'll be fine as soon as I disconnect all this lighting and pump stuff. At least one of the 12V power supplies has burst open.

[fwm891]

Looking good Chris, I doubt the power issue will cause you too much trouble.

Can you not build over the wall to keep your building lines straight, that will certainly help with tracks when you run your roof across the 'office'.

Definitely a project to follow...

Good luck with the build

[yesyes]

Thanks Francis.

You mean build the bottom of the obsy around the walls as outlined but make the obsy walls straight above the stone walls?

[Gina]

So glad you're in your new home at last Chris and getting on with planning your obsy I hope you'll both be very happy there

I agree with Francis if it's possible. You want a straight run for the track and I think rolling the roof off over the warm room is best - makes for a nice tidy structure. Looks like you've got a nice space there and will have a nice sized obsy

What's the sky like there and how's the view of the sky?

[yesyes]

Thanks Gina.

What I was thinking is to make the track straight and make it a bit like a bridge (for lack of a better word) where the obsy narrows. But making the obsy wider above the wall would give me a little more space inside as well.

I will probably have to make the obsy walls in panels as the obsy will be very close to the fence on 3 sides. I won't be able to get to the outside of the walls once they're up.

[Gina]

Yes I noticed that. Do you think you'll be able to make the building modular so that you can sort of take it apart for maintenance - both of the obsy walls and the fences?

[yesyes]

What's the sky like there and how's the view of the sky?

Not the best I'm afraid. Nothing like your skies and views. I'm surrounded by houses East and West and a stone throw away from the centre of town, so there's a lot of light pollution. The good thing is that the garden is on a slope that falls towards the South. So I will have a relatively low southern horizon. There are also no larger trees around, except for one quite tall but narrow one almost exactly North. I'll still be able to see Polaris though.

So not ideal conditions, but I'll make the best of what I have.

[yesyes]

Yes I noticed that. Do you think you'll be able to make the building modular so that you can sort of take it apart for maintenance - both of the obsy walls and the fences?

Now I wish IKEA made observatories...

Yes, I'll have to make it modular in some way. Although I do dread the thought of disassembling the obsy just to paint the fence. I shall give that fence (at least the one on the back) a good coat of preserver before starting to build things in front of it. The 2 fences on either side aren't really fences, more like trellis type structures and I could probably paint through them from the neighbour's gardens if it became necessary at some point. They both have a right of way through our garden, so I think they won't mind if I went though theirs occasionally.

[Chris]

Good luck Chris, I'll be following your progess with this, it looks like a challenging space. After examining multiple ideas over a fair amount of time I too found that running the RoR over the warm room was the most space saving option, if your obsy is on the small side like mine then you can even run the RoR futher than the warm room onto some large triangle angle brackets which are off the ground, this allows for more open sky when rolling the roof back. I'm building my angle brackets at the moment, all compact and neat without poles sticking in the ground in awkward places:)

[JamesF]

Nice to see this happening at last, Chris. I know you've been waiting a fair while

James

[yesyes]

Thanks Chris and James. I'm so glad it's finally happening.

Chris, I've been following your build with interest. Before we found this house I thought I would most likely end up with a long narrow garden like yours. So I followed your build with special interest. But now this garden is different.

I don't think I can run the roof beyond the warm room as that would reach into the neighbour's garden. I'll have to make the warm room at least half the length of the obsy. The warm room will double as my electronics tinkering workshop so I want to have that as big as possible.

What (free) software do people use to plan their obsy? Is Google Sketchup still the best but not ideal?

Or do most people just buy timber and get started?

[JamesF]

I think Sketchup is very useful for getting an idea of how everything fits together and how much space there's going to be.

James

[fwm891]

Thanks Francis.

You mean build the bottom of the obsy around the walls as outlined but make the obsy walls straight above the stone walls?

Yes. It would give you a ledge/shelf to put things on!

Once you get a better idea about layout build a model - it helped me no end when establishing how big a space i needed so the scope didn't foul walls etc, and also what restrictions the obsy causes for viewing with the scope on east or west sides of the mount.

Because I have buildings to the NW, N and NE I knew it was pointless making an obsy that exposed that part of the sky to any great extent. That enabled me to make what seems a very compact obsy with a very small roof movement to open all the sky visible. Angling the front end of the roof at 60° was the key feature for the small roof motion.

[yesyes]

Would you use the wall to support the joist? Or rather make it so that it does not touch the wall?

[fwm891]

Would you use the wall to support the joist? Or rather make it so that it does not touch the wall?

If the wall is stable why not. The only thing there is whether what appears to be a dry stone wall can ever be really stable. I'd take a joist across the wall so its not touching the wall and be completely independent. You can always fill any gap between the wall and your obsy with expanding foam to keeps creepy crawlies out!

[Chris]

50/50 would be good with an extra 6" on the RoR for an overlap so as to prevent water ingress. Even with the roof fully open with this configuration it would only over hang the 6" which you might get away with as it probably wouldn't cross the boundary between you and your neighbours.

Thanks for following my build, I'm competing with Gina for the longest build thread:D

[fwm891]

50/50 would be good with an extra 6" inches on the RoR for an overlap so as to prevent water ingress, even with the roof fully open with this configuration it would only over hang the 6" which you might get away with with the boundary between you and your neighbours.

One thing I wonder with RoR obsy is how often you actually need to fully open the roof? It would be nice if you can use the RoR as protection from wind etc., when viewing south (or anywhere) have the roof pulled so that it covers most of the scope - should help with dew as well. Viewing north or around the zenith is a different matter but I think the obsy can be designed to help the observations rather than just a cover for a scope on a pier...

A dome will give the best protection but I don't see why a RoR cant be designed to provide better shelter in-use.

[Gina]

Yes, I do that sometimes. Mine rolls off roughly to the west as you probably know, so when Imaging something not long risen (like Orion) I don't need the roof open much if at all - just lower the flap on the east wall. Keeps wind and dew off.

[Gina]

Actually, that fold down top on the end wall has proved very good. If you do the same Chris you'll have to have it folding inwards like me as you're too close to the fence for it to fold down outwards. If you do that make sure there's plenty of room between thant and your pier - my pier is a bit on the close side. Not enough to be a real problem fortunately.

[yesyes]

Yes, I was considering a fold down flap on the south end. Doesn't make sense on the other 2 walls as the neighbouring houses (including my own) block the view anyway. If there wasn't enough space to fold it inwards, I could make it slide down or just removable.

[Gina]

Sliding down is an interesting idea - hadn't thought of that. Wonder how difficult that would be. Hinged is easy and easy to weatherproof.