How I blundered into making a telescope
The Dobsonian mount
(contains approximately 450Kb of pictures)
New work in progress (aperture fever !)
Links to Telescope Making web sites
The Dobsonian mount was made from plywood pieces which were lying around
from earlier projects. The aluminium angles were purchased.
While not particularly steady, the whole frame is light, balanced and
can be held and rotated smoothely with one finger.
It can be disassembled in ten minutes, and assembled in another ten.
Alignment takes somewhat longer.
Above left: An earlier mirror mount, not used in the final assembly.
The final one used a circular plywood piece mounted on three springs for
alignment.
Above centre:The aluminized mirror, in the thermocole box made
to store it when not being used, along with some of the eyepieces.
Above right: The spider, made from bicycle spokes, and a piece
of PVC plumbing pipe (black). The diagonal mirror is mounted on a smaller
PVC pipe (grey) whose one end is cut at 45 degrees and ground flat on fine
emery paper.
The eyepiece end.
The eyepiece moves in tube which is a PVC pipe (grey) bonded
with epoxy to a matching hole on the sheet of veneer. The upper veneer
sheet is attached to a matching lower sheet with screws. Tightening the
screws holds it fast on the aluminium frame. The whole assembly can slide
along the frame for alignment. The side opposite the eyepiece is now covered
with black paper . The paper also extends out to form a hood around the
frame . This helps in reducing light scattering into the eyepiece.
The mirror mount end, with the mirror attached. You can see the reflection of one of the aluminium angles. The manufacturer's label can be seen stuck to the plywood behind the mirror. All the inner facing surfaces have since been painted black. A tube made of black cardboard covers the mirror and extends halfway down the frame.