To help in pointing 20 inch f4 scope, my trusty 6 inch f4 Dobby (shown in its original shape below) was converted into a giant finder. I had to reduce the weight of its optical tube assembly, so new fiberglass / sonotube composite was made.
Focuser was changed to a small 1.25 inch PVC tube fitting mounted in a block of maple and the spider was replaced with a single bend hacksaw blade (see an article written by Gary Seronik in April 2002 issue of Sky and Telescope):
Both above part as well as a red-dot finder were attached to the new tube (lined inside with glued wood chips):
6 inch f4 mirror was also fitted into new 9-point mirror cell and mounted in the finder:
Plywood arcs (with nylon adjustement screws) were bolted to secondary cage rings and the finder was attached with bungee cords (pay attention to a safety cord ;-)
Back to 20 inch scope
Number of visitors:
© Jan Wisniewski