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The Linnhe Observatory web site

These pages feature extensive construction details for my observatory completed in the summer of 2001 for a Meade LX200 10" f/10 Schmidt-Cassegrain telescope

page 6


The shed section and frame

The whole idea is to convert this shed so that the roof section is mounted on a wooden frame with eight wheels (four each side) to be rolled backwards on rails away from the shed underneath. The shed section will also need strengthening with a wooden frame around the top of the walls to support them and the rails on which the roof section sits. This frame needs to be anchored in the ground with posts in each corner and the shed panels essentially screwed to it. This forms a very solid structure which stands up to gales (frequent here) and the moving mass of the roof. The rails need supporting out beyond the shed for the roof to move back onto and this section is also a simple wooden one. OK, sounds easy yeah? :-)

The shed section complete with frame, rails and rail support image

The shed section complete with frame, rails and rail support

This is what the finished shed section looks like. Looks simple enough but it took quite a bit of planning to work out the details. Let's start at the beginning...

Removing the corner sections for frame corner posts image

Removing the corner sections for frame corner posts

The walls of the shed are screwed to a bottom aluminium base rail on which the shed sits. Normally the walls would be screwed to the aluminium roof frame which, apart from supporting the roof, ties the walls together forming a solid structure. But here the roof section will be separate so a wooden frame is required around the top of the walls to support them. The base rail would normally be screwed down at the corners with the supplied anchor kit but as each corner requires a corner post for support and strength I decided to concrete these into the ground. I would have to concrete the 'missing' corners of the pad anyway, so initially designing the pad as an octagon was a blessing.

Starting to construct the walls image

Starting to construct the walls

With the base rails down, the corner and door post panels are attached held together by the side braces. These are shaped into a tube with the underside edge being slightly open, which makes them quite flimsy and not really up to supporting the middle of the walls. I placed a single long piece of wood (made exactly to the internal dimensions of the braces) inside these braces to strengthen and straighten them and to give additional purchase to the many screws that will be screwed into it.

The walls are complete as the sun goes down image

The walls are complete as the sun goes down

At this point the walls are just screwed to the base rail and the side braces. Be careful with the supplied screws. They go through pre-drilled holes in the walls and into tiny holes in the aluminium rails and braces. These can strip very easily. I had to use a size larger (1"x10 stainless steel panhead self-tappers, Screwfix 8893) screws on the several occasions I did this. Use a low torque setting on your power driver. Also use two security screws per panel - I used 8x1" star pin button stainless steel self-tappers (Screwfix 3669).

The door detail deviates from the normal Yardmaster plan. The door pelmet (shown spanning the walls either side of the door opening above) and the door tracks are normally attached to the roof section. They can be screwed to the walls either side of the door opening. The door tracks are in two sections and meet in the middle. This joint can be strengthened by screwing the pelmet to the door tracks behind (the silver line topping the front wall in the image above). An additional metal brace was also made up to span this joint and screwed through the underside of the pelmet and tracks. Before you install the track don't forget to insert the door runners into the track for the doors to be attached to later.

 

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