Here is the scope I built in 2003. It took about 6
months of on-and-off work to grind the mirror and build the structure.
The mirror is made from BVC glass, and the overall design is
closely based on the well-known Kriege/Berry design. One
difference is that the mirror box is made a bit oversize, to allow the
secondary cage to nest within it for transportation. The truss
tubes are concealed beneath the ripstop nylon shroud, which I leave on
most of the time. |
A close-up of the secondary cage. The focuser is a JMI RCF unit, and the finder is from Orion. The finder bracket is homemade; it's a bit lighter than the one that came with the finder. |
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Here is a view of the other side, showing the altitude encoder for the DSC setup.  |
Here is a shot of the rear end. The mirror cell design (6-point) is stolen right out of the Kriege/Berry book. You can see that BVC glass is black! The three white strips are simply pieces of thin plastic that keep the black steel support bars in the proper position. You can also just barely see the azimuth encoder. In the base of the rocker box there is also a Dave Ek encoder interface circuit. Across the bottom of the mirror box you can see a few strips of black-painted steel. These counterweights are needed only to balance the finder scope; if I remove the finder scope and attach a red-dot finder, I actually have to add a few ounces of weight at the top. I carefully calculated the weight and balance of the design before I started building it, and the actual center of gravity ended up quite close to my prediction.  |
Here are some more pictures of the scope, here are some close-ups of the mirror and its cell, and here are some pictures of the mirror polishing setup and the Foucault tester I made.