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.7: Counter weight

Now there is August and the sky becomes darker. I must have the observatory up and running so I don't miss any chance to take exciting photos. It's just some small details missing now. One thing is more important than the others, the roof must be easy to operate. I need the counterweight in place to make the roof easier to operate.

Last time I prepared the counterweight with four threaded M8 holes. Now I drill the corresponding holes in the wooden arm.

The counterweight moves about 0.8 meters back and forth when opening and closing the roof. There isn't very much space under the floor so it must fit exact. As you see when the roof is in open position it's touching the pier, not good!

I need about 15 mm more space here between the pier and the counterweight. The slit you see I will weld together later. I don't know what this steel beam had been used for earlier.

I don't have tools to work with a big steel bar like this. I had to drill a lot of small holes and with the hammer knock it off. Lot of sharp metal spoon over the rock, I had to take a strong magnet to get rid of them.

When the roof is in closed position I got another problem, now it hits the wooden stud in the other end. Wood is much easier to work with, just had to cut a opening for it.

Now I can close the roof again.

Here I will will do an attempt to install an electric motor to control the the roof. I don't think it will be too complicated.

And did it work?
Take a look at the video here:

I need almost no force at all, only when closing it the in the first part. A spring will handle that problem.