Astrophotographers see the FSQ-106EDX4 as one of the best astrographs available for amateur astronomers. With a focal length of 530 mm, an image circle of 88 mm and a field of view of 9.5°, it acts as a telephoto lens for the most powerful CCD cameras and digital cameras on the market.
Based on a Quadruplet Petzval optical formula including ED glass, the FSQ-106EDX4 is optimized for wide-field imaging of the deep sky. It has a native flat field, a camera angle adjuster (CAA) and an oversized rack-and-pinion focuser with 1/7 microfocuser. To minimize space requirements, it is equipped with a retractable dew shield.
Two focal reducers (0.73x and 0.6x) are available as options.
Specifications
| Optical specifications | |
| Objective | Petzval Quadruplet with ED glass |
| Lens cell | Highly air-spaced quadruplet. 4 lenses/4 groups. 2 x S-FPL53 ED lenses |
| Coatings | Hard multicoatings |
| Diameter | 106 mm |
| At prime focus | |
| Focal length | 530 mm |
| Focal ratio | F/5 |
| Metal Back Distance | 178 mm |
| With focal reducer RD-QE0.73X | |
| Focal length | 385 mm |
| Focal ratio | F/3.6 |
| Image circle diameter | 44 mm |
| Metal Back Distance | 72.2 mm |
| With focal reducer 645 RD QE0.72X | |
| Focal length | 380 mm |
| Focal ratio | F/3.6 |
| Image Circle Diameter | 60 mm |
| Metal Back Distance | 56.2 mm |
| With focal reducer F3 RD 0.6X | |
| Focal length | 320 mm |
| Focal ratio | F/3 |
| Image Circle Diameter | 44 mm |
| Metal Back Distance | 56.2 mm |
| With Extender EX-Q1.6X | |
| Focal length | 850 mm |
| Focal ratio | F/8 |
| Image circle diameter | 44 mm |
| Metal Back Distance | 117.5 mm |
| Mechanical specifications | |
| Length of the optical tube | 675 mm (580 mm with retracted dew shield) |
| Diameter of the optical tube | 125 mm |
| Weight | 7.0 kg |
| Focuser | Rack-and-pinion with 1/7 microfocuser |
Spot diagrams
