The major design constraint on this scope was that it be light enough for me to carry up and down the basement steps where it is stored. It breaks down into pieces that met that goal. The optical tube with the mirror weighs 33 lbs. 20 lbs of that is the mirror that I ground and figured myself. This scope incorporates several ideas from many other people on the net. In particular from
Jim Miller
the use of a bicycle wheel rim for the upper ring and binder clips to attach it to the truss poles. Jim also used three trusses instead of the usual 4. The mirror is 1 inch thick plate glass and has a fan at the back for cooling. Eventually the scope will be motorized and computer controlled with Mel Bartel's stepper system. I attach a light weight foam baffle placed around the UTA that is not shown. This scope is still a work in progress and I will update this site as it progresses.
Rocker
The rocker and base have been modified from the original pictures above. The rocker now is a flex rocker design with aground board made stiff by an aluminum ring made of 1 inch square hollow aluminum tubing with kerfs cut into it to allow a ring to be formed. The top is Masonite and is attached to the aluminum ring using metal screws. It has not been moisture proofed yet. Below is an picture of the bottom side.
The next image is from the top side. The 4 bearing are roller blade bearings. One has been replaced with a piece of teflon to make a little more friction. I will be trying to add friction at the central pivote and add the 4th bearing back. Eventually the scope will be motorized and the bearings will be needed for that configuration.
Spider
The spider is made from aluminum roof flashing and held in tension. Its vanes are offset to reduce induced vibrations as described in Texerau and on Mel Bartel's site. The diagonal holder is also a design I found on the Web at
Diagonal holder
I machined the focuser from Aluminum using the design from Jim Sapp at
The mirror cell is similar to a design by Nils Olaf Carlin. It uses only two collimation bolts and is accessable from the front while looking through the eyepiece.
Nils Olaf Carlin's Web Page
The 18 point cell rockers are mounted inside the square aluminum tubing cell frame. That reduces the cell thickness and helps shorten the OTA length.
The next image is from the top side. The 4 bearing are roller blade bearings. One has been replaced with a piece of teflon to make a little more friction. I will be trying to add friction at the central pivote and add the 4th bearing back. Eventually the scope will be motorized and the bearings will be needed for that configuration.
