Focusers, Mirror Cells, Para-Focal
Rings & More
After twenty years experience as a pattern maker in the aerospace industry,
Dave Rubenhagen was "down sized". Instead of lying down to surrender,
Dave setup shop and founded DAR-Astro.
All of Dave's products are his original designs, and 100% made in
Canada. Custom modifications for an extra charge is available.
Currently Dave makes focusers in 1.25" and 2", but rounded and flat base,
mirror cells from 6" to 12.5", ParaFocal rings (very popular with some
owners of Zeiss bino-viewers), and the focusing assembly for the SanJo
This page is still under construction and more products will be slowly
added. Right now plans are in the works for larger mirror cells in
the 16", 20 and 24" range to be brought out in the 2-3 years, but honestly
they exist at this moment only as auto cad drawings. We will keep
you up to date.
DAR-Astro 12.5" mirror cells, top and rear view. 9 point support
on the 10" and 12.5", 3 point support on the 8" & 6" size. We
are looking at an 18 point support on the 16" model and perhaps a 27 point
support on the 20" and larger models.
Image one shows the 1.25" focusers, one fully retracted, the other fully
extended. Image two shows the 2" focusers. In each picture,
I have placed a Vixen 20mm Lanthanum in beside the focusers for scale.
The bronze barrel is the coarse focus (9 threads/inch) while the aluminum
is the fine focus (20 threads/inch). Tested operational at
-30C below AFTER being frozen solid for two weeks in a row.
That fact probably does not mean much to many of our world-wide customers,
but we have a running joke here that most telescope designers obviously
never used their products in a Canadian winter. For our customers
in Canada, Alaska, Russia and the Scandinavian countries, you'll love these
focusers in the middle of January - not only do they never freeze up, you
can easily use them with gloves on!
For the rest of our customers in warmer climates, they work great in the
These focusers are intended for visual use on newtonian telescopes.
We are working on a modified version with a locking focus that would
be suitable for astro-photo or CCD work.
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