The design is a singlet f19 plano convex objective lens followed by a series of small corrector lenses to remove aberrations. The path length is folded by two flat mirrors, high reflectivity coated for maximum light transmission. All other air-to-glass surfaces are broadband coated in the visible range.
The specifications are:
Objective diameter 203mm (8 inches)
Focal length 2400mm (f11.8)
Tube diameter 288mm
Tube length 1550mm
Tube is carbon fibre, painted a durable white colour, with gloss black end caps.
OTA weight 10kg
Field of view 0.8 degrees
Strehl ratio 0.97
Supplied with Moonlite 2 inch focuser and 8 x 50 right-angle finderscope.
Web site: www.firefly85.com
These instruments are hand made to order, and delivery is normally 8 to 10 weeks after receiving a 50% deposit.
Here is a view of the finished instrument.