My astronomy project:
Building an Observatory
(or a playhouse for big boys and girls)

Content:

1. Frame
2. Roof
3. Roof mechanics
   1. Different designs of roof mechanisms
   2. Building the mechanism for the roof
   3. Hatch Hinges adjustment
   4. Roof Rail Mechanism
   5. Arm Rail Guiders and Stoppers
   6. Counter weight arm
   7. Counter weight
4. Floor

Note:
I take no responsibility or liability for what are written here, you use the information on your own risk!

Page III.4: Roof Rail Mechanism

I have chosen to have a rail that the roof can roll out on one side and arms on the other side. The arms are already finished. To get a low friction it must have wheels that roll over the rail.

One big wheel that take up the vertical force and two small wheels that guide the roof horizontally. This is just a model for testing that it work as I expected it to do.

Here is it mounted under the backend of the roof.

It worked perfect, it was not very heavy to open it, later I will have counterweights and springs that reduce the needed force to open and close the roof. Now I just have to fine adjust the details. Now you also see the most important of this construction, the arms move the roof down when fully open. You get a low horizon without hatches around your building that can make the construction weak. The two roof construction also let you have the telescope above the walls and still can open the roof.

I just have one rail and it's thin to not let the snow accumulate on it. In the background you see my second pier where I do visual observations. Here I will have my 25x 100 mm binocular.

Here a view how the end of the roof rolls out over the rail.

Emergence stop! You never know what will happen!

Here the roof is in the out position. Now I have the details how I will make the final version of the wheel holder, as you see the side wheels could be lowered a bit.

This is the final version (I hope), no wooden parts, all metal, much stronger.

The side wheels are now in much lower position, if I find a 20x 80 mm aluminum beam in future I can replace this wooden made part with that. A fourth wheel on the underside that hold the roof down in heavy wind could be wise to have.

Roof in closed position.