Optical design
Instead of buying additional flatteners, calculating the back focus of the flattener, or making a tedious connection to set the correct distance, astrophotographers can simply equip it with all sorts of photographic accessories, keep the object in focus, and then the entire optical system is perfect for the figure set.
 
High quality glasses
The FF80 has an aperture ratio of 1:7.5 and a focal length of 600mm. The FF80 is a quadruplet design with two ED lenses, allowing excellent control of chromatic and other aberrations. With its self-leveling design, the FF80 offers great advantages for astronomical photography. It offers the full-frame image circle and has a fine spot diagram with only tiny distortions of the peripheral stars.
 
Practical details

The FF80 comes with an extendable dew cap, a high quality CNC milled and painted tube and decoratively designed parts. The OTA weighs 3.9 kg, the entire package with pipe clamps etc. weighs 4.7 kg. The sturdy 3" focuser comes with a 360° rotator with dials and a viewfinder shoe. M76, M68, M54 and M48 camera adapters are also included, and the M48 adapter has an M48 female thread for installing 2" filters.

The back focus is always measured with the draw tube completely retracted:

♦ 115 mm from M48x0.75 external thread
♦ 135 mm from M54x0.75 external thread
♦ 155 mm from M68x1 external thread
♦ 168.5 mm from M76x1 external thread

Opening: 80mm
Focal length: 600mm
Aperture ratio: f/7.5
Optical system: Quadruplet with two ED elements
Lens: Triplet lens with air gap
Corrector: Single Element Corrector
Coating: All surfaces are multi-coated
Illuminated and corrected image field: 44 mm diameter
Focuser: 3" rack and pinion focuser with reduction
Adjustment range: 110 mm
Visual working distance: 148 mm（from the end of the 2" eyepiece holder)
Working distances for screw connections: 115 mm（from M48×0.75 external thread), 135 mm（from M54×0.75 external thread), 155 mm（from M68×1 external thread), 168.5 mm（from M76×1 external thread）
Filter thread: 2" filter thread is included in the M48 camera adapter
Rotation option on the extension: Yes, with scale
Transport length: 448 mm (with 1.25" adapter) to 477 mm (with all four photo adapters)
Working length (dew cap extended): 540 mm (with 1.25" adapter) to 570 mm (with all four photo adapters)
Net Weight: 3.9kg
Total weight: 4.7kg


♦ FF80 Apo
♦ CNC clamps with carrying handle and prism rail
♦ Viewfinder shoe mounted on the focuser
♦ Set of 4 thread adapters