These are my first homebuilt telescopes. I made them in spring of
1999 in anticipation of a three-month summer trip to my Andean
fieldsite in southern Ecuador. I bought two 4-1/4" f/4 primary mirrors
and secondaries from Edmunds, and quickly built the vinyl-tubed
prototype. After working out some bugs (like the insufficient baffling at
the top end) I started work on the luan-and-mahogany travelscope.
Overall the mahogany scope is 17-1/2" long and 6" wide, and fits into
an airline-legal carry-on bag. For travel the front end is closed by a
cover held in place by 1/4" shock cord.
Initially I intended to use the scope on a sling, but in the field quickly
found that it was impossible to aim it, so I bought a cheap photo tripod
(fortunately, I had installed a mounting plate just in case before I left for
Ecuador). I had to aim the telescope by sighting along an edge; the
red-dot finder was added later.
The hexagonal tube was easy: cut six strips of luan on the table saw,
tape the seams on the back (out) side, brush on some glue, and roll the
tube up and hold it with more tape until the glue dries.
The secondary holder was fabricated from 1/8" aluminum L, and bent to
reduce diffraction spikes. I put a little stick-on star on the primary to aid
The mirror is carried on an 1/8" aluminum plate, spring-loaded against
the cell. Initially I covered the back end of the scope with a hexagonal
piece of luan, but this delayed mirror cool down, so I removed it. Had I
known, I would have cut a large hole in the mirror carrier, but by this time
the mirror had been RTVed in place and I didn't want to mess with it.
Ross Sackett's amateur telescope making
My telescopes and ATM Projects