The optical scheme consists of a triplet with an FDC100 glass lens (FPL53 equivalent) and a full frame ED doublet near the focuser. The OTA is made of the highest standard, in aluminium with internal diaphragms to eliminate reflections and with a granite 3.2" rack-and-pinion focuser with 1:10 reduction. At the end of the focuser there is a collimating field rotator with an M63 thread and an M63 to M48 adapter with the possibility of inserting 2" filters inside.

There is no need for a particular back-focus, at the classic distance of 55mm the focuser pulls out by 6mm, a favourable position particularly when using heavy ccd cameras. A robust pair of rings, vixen bar and a carrying handle complete the scope.

Thanks to its compactness and weight of only 5.8kg, it can also be used on small, portable mounts such as the iOptron CEM26, GEM28 or EQ5/HEQ5; with its fast F/5 focal ratio, it is an exceptional astrograph for colour and black-and-white cameras, particularly with narrowband filters.

Characteristics:

• Triplet ED Apo lens design with FCD-100
• Aperture 90mm, focal lenght 450mm, f/5.0
• 3.2" focuser with 1:10 reduction
• Integrated doublet reducer/corrector
• CNC tube rings
• OTA lenght of 38cm
• Weight only 3.0kgs

• OTA 90/450mm Triplet FCD-100 ED lens
• 3.2" focuser with reduction
• Apapter M63 - M48 with filter holder
• CNC tube rings
• Vixen level dovetail