The floor (6' square) uses 2x4 framing and is covered by ½" plywood (good one side). The wheels are located in the centre of each side and carry the weight of the walls, roof, and observer.

In my version of MGRO, the telescope/tripod also sits on the floor. Vibration proved to be a problem when looking through the 'scope, so I also added 2 wheels close to the centre of the floor. This stiffened the floor sufficiently to allow visual observing up to 150x with my C8. Of course, if you use a pier through the centre of the observatory, vibration will not be a problem! It all depends on your intended use for the observatory.

Hey -- put a hitch on the front and it could be a mobile observatory! Well, maybe not... The floor is 2x4 framing 6' square with the joists on 24" centres.

In order to attach the wheels, an extra cross piece was added. Holes were then drilled through the 2x4's. The holes look crooked here because they were drilled from the other end. Use of a drill press (or even just a more highly skilled operator!) would yield parallel holes -- of course this crookedness is covered by the plywood!

The floor framing is covered by ½" plywood (good one side). Again, to save money, I pieced it. One sheet of 4'x8' ply covered 4'x6' and 4'x2' areas and I was able to buy a 2'x2' piece at the store to cover the remaining corner (upper left in the picture).

It was NOT a good idea to stand near the corners of the floor at this point, since all the support is at the centre of each side! This problem disappears when the 4 walls are added.