Alternative DIY Obsy - or am I barking up the wrong tree

[lukebl]

Hi,

I have got to the stage where I really, really need a permanent obsy, but can't justify the cost of a 'proper' one.

So, I had the brainwave of adapting the children's Play House (sorry kids). Here is the playhouse (excuse the garden clutter, although I know everyone likes to look at other people's mess):

It is one of those ones with an off-centre ridge line, so that one side of the roof (the one with the cute little chimney) is longer than the other. I thought, if I reorientate it so that the big roof side is facing south, then replaced the roof with two flaps/shutters (one going up and one going down), I would have a nice opening for the scope. All I need to do is construct a pier for the scope, thus:

Obviously, viewing NW, N and NE would be restricted, but otherwise it seems perfect (and perfectly disguised for security purposes as a humble childrens play house!). The difficulty might be manhandling the roof flaps in the wee small hours of the morning, particularly the upper one. Or has anyone else got any ideas for the roof?

Don't worry, I've sold it to the kids on the basis that:

a) they don't use it enough anyway and,

they can have the other big shed as their own play room and,

c) my need is greater than theirs!

What do you think. Am I barking completely up the wrong tree? ...or just plain barking?

[Herakles]

Can't see why not Luke , I am planning on doing my roof panels that way as well , hinged , rather than the trad' ROR method.

Clear Skies

Pete

[Bizibilder]

Those roof flaps could be extremely heavy unless completely remade from lighter material. Also you will need access to the NCP for alignment at least (I know it can be done without but having Polaris accessable makes life easier).

My own view would be to recycle some of the timber to make a "standard" roll off roof structure ie all the walls the same height and a simple roof with enough slope to shed water. Your site seems quite "treefull" (nice new word!) so choice of site will be important to get the best views - so you will probably have to dismantle the whole thing anyway. Just my 2p.

Sorry Luke - I just realised it was your post!!!!!!!!

[astromerlin]

If I was going with the plan, I'd attach bars to each end of the roof flap/flaps with counterweights to offset the weight of the flaps which could also be a means of opening and closing the flaps also.

[lukebl]

Those roof flaps could be extremely heavy unless completely remade from lighter material. Also you will need access to the NCP for alignment at least (I know it can be done without but having Polaris accessable makes life easier).

My own view would be to recycle some of the timber to make a "standard" roll off roof structure ie all the walls the same height and a simple roof with enough slope to shed water. Your site seems quite "treefull" (nice new word!) so choice of site will be important to get the best views - so you will probably have to dismantle the whole thing anyway. Just my 2p.

Sorry Luke - I just realised it was your post!!!!!!!!

Thanks Bizi. Catch up with you later! And thanks astromerlin and herakles.

Yes, I had thought that the roof weight might be excessive. Might explore the option perhaps of a 'softer' material, such as something which can be rolled up like a tarpaulin.

As for the location, I was planning to move it to the northern side of the garden where I've got a fairly good southerly view. As the mount would be permanent I was going to rely on drift alignment to get it right (which I'm pretty good at now!)

[lukebl]

On the roof issue, just wondered if some sort of roll-up roof would work. Something like this:

...and, if so, where could I get something suitable?

many thanks.

[Bizibilder]

That's just triggered a thought!! Somewhere on the web an American has built an observatory with two "roller" type garage doors. They are mounted on the tops of the walls and "close" by unrolling upwards to the apex - I can't remember how he sealed the join! So it has been done before and apparently worked!! I also expect that it would be quite expensive unless you could find a couple of second hand door assemblies. (I also have a feeling his were motorised as well (more munny!!!)

[michaelmorris]

Why not have the whole roof sliding downwards on two or three rails? A pulley arrangement could be installed to help with raising it.

As I see it, the danger here is that the solutions to your (by your own admission) less than ideal design for an observatory might end up being far more complex and potentaily expensive than a simple roll-off roof shed conversion. The problem I can see with your designs is the opportunity for rain to drive into hinged joints. From my research, this seems to be a recurring problem with many 'split roof' designs.

If you want to re-use the existing structure, I can suggest a more versatile design have the whole shed on tracks and use it as a run-off shed. (like Sir Patrick Moore and Martin Mobberley). Obviously, this depends on the weight and rigidity of the structure and space to have it move.

[lukebl]

Lots of things to think about there.

Amazing how something starts off as an idea for a simple adaptation of something you've already got, and turns out to be far more complicated than the option of starting from scratch!

[lukebl]

Here's another idea. The roof can go up and down on runners and a pulley system (sorry Michael, is this what you meant?).

Not sure if it will work, but I really enjoyed doing the animation!

[Breakintheclouds]

Love the animation! I guess that could work if you had some sort of right-angled piece to rest on top of the closed roof to ensure water-tightness

[lukebl]

And here's a slightly more refined drawing showing the principle:

Well, it might work. Will I find the lack of a northern aspect a problem? If necessary, I'll just take it off the pier and put on the tripod.

[Demonperformer]

Knowing nothing about observatory building, it occurs to me that if you need a northern view to be able to see Polaris, as it always stays in the same place, you would only need to put some kind of opening window in the appropriate location on whichever wall/roof was appropriate?

[lukebl]

Knowing nothing about observatory building, it occurs to me that if you need a northern view to be able to see Polaris, as it always stays in the same place, you would only need to put some kind of opening window in the appropriate location on whichever wall/roof was appropriate?

Not too bothered about seeing Polaris. I'll just do a drift alignment when I set it on the pier. And as it'll be a permanent fixture, I shouldn't have to do it very often.

[michaelmorris]

Here's another idea. The roof can go up and down on runners and a pulley system (sorry Michael, is this what you meant?).

Yes, your second (excellent) animation has it exactly how I envisaged it..

[lukebl]

I guess I would need to ensure that there was some sort of safety mechanism to stop to roof shooting off down the runners unexpectedly at great speed and decapitating someone, which would be somewhat inconvenient.

[Breakintheclouds]

I guess I would need to ensure that there was some sort of safety mechanism to stop to roof shooting off down the runners unexpectedly at great speed and decapitating someone, which would be somewhat inconvenient.

Good point! But I guess a system like this would almost certainly want counterweights, and they should help obviate that risk if they're set up properly. But additional safety measures (e.g., removable pegs in the runners?) wouldn't hurt

[Earl]

Id say go with the slid off route, some slide bolts with padlocks should hold it in place until the "Keyholder" opens it for service

[Tim]

The kids are gonna hate you!

Can you stand up in there?

[Doley68]

Hi all,

I read your thoughts about a "soft" roof with interest as I have just finished converting a 8' x 10' shed into an observatory & have used this very idea!

I had a besoke cover made which just replaces the roof. I have 3 removable supports which stop any sagging and it is held in place with a bungie cord threaded through eyelets as usual.

I unhook the bungie, go inside & remove supports and fold/gather it back. Takes 2 minutes!

The whole roof weighs just 5kg & no run off area to contend with.

The cover cost £170. This was the whole cost really.

Photos to follow.

[lukebl]

Can you stand up in there?

Yes, it's got quite good headroom and with the roof down it will be even better. There's even a little upstairs shelf/bunk on the northern side where I can rest the laptop/eyepieces/wineglass.

I read your thoughts about a "soft" roof with interest as I have just finished converting a 8' x 10' shed into an observatory & have used this very idea!

It would be good to see a pic this if you can.

I'll post pictures of this venture when it happens!