Precision machinist built 8" f/12 for sale


8" f/12 ultra light lunar planetary OTA

Actual focal length is 93". During mirror fab, if left as a sphere there would be ~1/4 correction error. So this mirror was then slightly aspherized to null far better than that limit. The primary blank is a lightweight Celestron SCT cast Pyrex blank. This uses center attachment to a light weight adjusting rear cell. Lunar planetary performance is superb




OTA is in 2 sections both 44 1/2" long. Upper is 3 1/2 pounds and lower is 11 pounds

All fastners are SS and hex wrench type. The focuser is modified for closest location, with shortened chrome ocular tube. It has very smooth movement.


8 each very light weight lathe turned rings at ends of truss assemblies and tube sections. All aluminum is black anodized. Truss tubes are epoxy wound G10 fiberglass. Light and rigid.


diagonal mirror is 1 1/4" minor axis (3% area)

Total weight with rings is 17 1/2 pounds. Aluminum tubes are white epoxy painted and the main center tube rotates smoothly in the felt clamp rings.


Focuser is shortened and is at max in travel, and still not in the beam.

Heavy tube rings are machined cast aluminum @ 6 pounds w/ 8x50 illuminated finder

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Contact Jim Riffle, 928-685-2261 (days only)