Roll-Away shed obsy - thoughts...

[Gina]

The animation isn't working Francis Nice drawing otherwise

[fwm891]

Animation updated.... Thanks Gina

[Gina]

That's novel Francis I wonder about the sealing against the weather though...

[fwm891]

Hi Gina, While the animation is just a simple outline at the moment my thoughts on this version would be that the roof/north-wall section would considerably overlap the other walls when it closes thus forming a watertight seal where all the various parts meet.

The floor inside would be sealed concrete, slightly higher around the pier (but not touching) and sloping down towards the walls, but always above the level of the wall bottom edges to prevent water ingress at low level.

The roof and north wall would both be covered with an epoxy bonded, rubberoid type weatherproof membrane, in-fact the whole obsy might be covered in this material, but I do like the look of timber and would prefer a timber clad structure if possible.

My only negative thoughts at the moment would centre around maintenance, at present even in bad weather I can potter around my scope assembly checking everything over, even plugging everything in and driving the axes a short distance in any given direction. This design would limit me to good weather maintenance as I would have to open the whole 'shell' to access anything. Also if I thought of changing to a larger scope in the future I would be limited by the compact space. But looking at the scopes others on this forum are using for imaging my MN190 should suffice for some considerable time...

What it would mean though is that I wont have any tracks for a roll-off-shed running across the garden, no roll-off roof tracks sticking out at high level, so the whole thing can be quite compact.

Thinking cap still firmly on so another version might spring up at some stage, who knows...

[fwm891]

More thoughts (blame the sunny weather!) This is an amalgamation of the two above. I like the idea of a fixed base to the obsy, but I also want some room around the scope to work on things while keeping the structure water tight.

Here the south wall is lowered and the north wall raised with the east/west walls angled to match. The roof then pivots on the east/west walls, dropping out of the way to the south side. I'm thinking of ali sheet over a timber frame for the roof with large overlaps on the east, west and south faces. The north edge will have the ali sheet extended to form an angled drip edge/shield to stop water ingress there. I can then put a door, probably not full height in the north wall for entry/exit. I like Olly's little computer cupboard, I'd probably look to place one in the north wall so I can put a laptop there to connect the scope when doing maintenance etc. Still looking to run the scope remotely from the conservatory on a desk-top machine.

Another animation to show my thoughts...

[Gina]

I love your animations Francis That looks very interesting and novel. Have you worked out the weight of the lift-over piece? I guess you wouldn't use in in a strong wind.

[nightvision]

Very nice animations, what are using to produce them?

BTW there are other obsy builds somewhere on the forum that have done something similar, they used pulleys and counterweights to make opening effortless and safe.

[fwm891]

Thanks Gina & Tony,

Final weight will depend on the roof framing and covering, 20 / 22 gauge ali wont be too heavy and will bend quite easily along all the fold lines.

It will be quite an easy shape to secure either shut or open if I'm out and its at all windy. Opening and closing I'd like to counterbalance it with either weights or garage door springs, but if its not too heavy, some puff-n-grunt will suffice!

I built the image up in PS CS3 Extended as a set of layers then used the animation tool with PS CS3 to create the animation and set the frame timings etc. Then saved as a gif file via 'save for web' option I resized the image in the save for web option so the file doesn't take too long to activate with a slower connection - i'm sure not everyone here has optimal downloads.

[fwm891]

I've been doing some scaled drawings today that enabled me to set a height for the top of the south wall and fix internal dimensions for the north/south and east/west walls. This also allows for other adaptions! I feel version 4 coming on....

Having layed out the pier, mount and scope I was able to get a better idea of just how much space around the assembly I would need to 'tinker', place electrics, hang flat panels etc., etc.

At present I park my scope pointing east with weights down, the top edge of the tube being level and at a height of about 70" (1.78m). If I change that to tube level and pointing south, that puts the tube assembly quite a bit lower and weights now sit on the east side of the pier. This lets me reduce the roof height, but doing that also makes it awkward, as in version 3 where I wanted to pivot the whole roof over the south wall and still have a clear unobstructed view.

My view to the north-east, north and north-west will be restricted by buildings so there is little point in trying to get the scope to view into those areas.

I find myself now thinking about a roll-off-roof. Because I'm not needing to look-to-the-north I don't need a roof that rolls the full length of the obsy. One of the goals I've set myself is not wanting tracks at high level or in the lawn. So, I'm thinking of scaling up a draw runner and use caster wheels set between two opposing 'U' channels to run the smaller sections.

This should allow me to keep the whole of the roof in one section, fold down the top of the south wall. The east/west walls would be halved (almost) vertically above the height of the south wall.

Once I've taken this idea a bit further I post the plans and elevations.

Boxy schematic for illustration only

[fwm891]

I think I'll be happy with this set-up. May need to make a few small changes once we make the move.

Dims are mm when looking at the plan drg. The roof rolls away with an internal clearance of about 6 ft (1.8m)

[Gina]

Very interesting

[fwm891]

Thanks Gina,

Quite interesting designing from the inside-out rather than going for a pre-made shed and then re-structuring it.

For my current obsy I built a scale model as the obsy was part of a bigger build, I will probably end up doing something like that for this one. The scope/pier/mount and the internal dimensions are the important bits especially as I'm building for a restricted (i.e. what I'm allowed!) space. Hence wanting to reduce or remove any external tracks to the ground or a high level so the obsy just takes up its own space, even when the obsy is open very little extra space is taken up and others wont be using the garden after dark anyway.

I decided to put a double 'U' channel down each side with one inverted thereby trapping the wheel inside the track. After your experience with the roof blowing off this enclosed 'draw-runner' approach seemed the answer.

The roof/wall overlaps on the north, east and west walls will keep water out with minimal additional sealing, but I still have to decide on a form of weather-proofing for the south wall as it has to first fold inwards slightly to allow the front edge of the roof to pass over it, before being folded outwards to rest against the south wall section.

I'd also like to give myself a little extra space for any upgrades that may occur in the future (can but hope!) a 10 or 12-inch scope would be fine.

Well I feel a foam-core-n-balsa wood moment coming on.......

Francis

[fwm891]

'U channel arrangement'

[fwm891]

I made a model yesterday/today of the observatory and the mount/pier/scope. Its been built to the same scale (10:1) I did the drawings to (mainly to avoid problem with conversions).

The track/wheel arrangement has been made from ice-lolly sticks to represent the wheels, with some timber strips to represent the tracks.

I've used some 4mm MDF I had in the workshop and this has been sized for internal measurements of the intended obsy as for the model wall thickness' doesn't really matter.

The photo of the north-wall with roof open shows that (some of) the wheels on the west wall actually come out of the track but those on the east wall because of the computer bay actually remain fully supported. It was this partially unsupported wheel base that made me use a second inverted track above the wheels to stop the roof tipping.

The folding south wall is not shown.

Hope you like...

[Gina]

WOW! That's fantastic Francis - lovely model

[fwm891]

Thanks Gina - I enjoyed buillding it, (next time it will, be ten times bigger and no MDF!)

Probably cover the roof with a thin (20/22 gauge) ali sheet. There's no complicated bending but I will need to join two sheets together to make up the width. The south wall flap and the computer bay will be clad the same. Then insulate them with some celotex or polystyrene sheeting. Walls will have a moisture barrier and insultaion plus a ply inner facing to neaten everything up.

[fwm891]

Well the old obsy is being stripped out as we get ready to move house, so once I begin the new build I'll start a second thread (I'm told I have to get my priorities right) I know exactly what MY priorities are :grin:

[fwm891]

Update. Although I'm sticking with the last version (see photos of model above) I've decided not to have a fold-down top to the south facing wall, but instead to take this section off completely, letting it sit in a cradle or hang off hooks on the south wall. It will be very light weight being a timber frame with celotex insulation and an aluminium skin.

This will enable me to shift the whole obsy that bit closer to the south fence line which will help with opening the view to the west a little more. East and south are petty much unobstructed.

[ollypenrice]

The 'what cladding' business is interesting. Everything like that is expensive here in France and the shed is not part of the workaday culture! I have never been able to find classic cheap UK shed cladding. Not only that, but the huge UV bombardment from the Sun means you need very expensive surface treatments. In fact the cheapest walls I've made were from Breeze block but that isn't always appropriate and if you are as bad a brickie as I am it is slow and painful.

Olly

[fwm891]

Olly - I'm coming down to using shiplap cladding over a timber frame (breeze blocks are out for various reasons - although very practical) then paint the shiplap with a reflective epoxy paint. Used EP on a few structures now and it holds up much better than standard exterior paints and doesn't seem to need excessive maintenance. Resistive to most chemicals and UV. You just have to work fast or mix small quantities as its a fixed working time once the two parts are together...

[Gina]

I use Ronseal Total Wood Preserver. Expensive but does the business. It's a spirit based product and in a different league from the wood preserver in the DIY shops. Put vapour barrier between the shiplap and the frame as extra protection. We are very exposed here.

[Gina]

Why am I telling you the Francis I'm actually telling everyone really

[fwm891]

I seem to remember the vapour barrier and the shiplap for some reason - not sure why :grin:

[Gina]

[Gina]

Your and Chris's help was much appreciated and is on full display

http://ginad.org.uk/weathergd/Webcam-big.html