ZWO FF131 f/7.5 APO Quadruplet Refractor Telescope
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- 131mm f/7.5 flat-field APO refractor designed for high-resolution deep-sky imaging
- 983mm focal length offers impressive reach for galaxies, nebulae, star clusters, and smaller deep-sky targets
- Quadruplet optical design helps deliver well-corrected stars across the frame
- No separate field flattener required, making setup simpler and spacing less complicated
- Generous 44mm image circle provides coverage for full-frame and smaller astronomy cameras
- Large dual-speed focuser allows for precise manual focusing and fine adjustments
- Includes essential mounting and imaging accessories to help you get your setup built faster
- Save when you bundle the ZWO FF131 with either the ZWO AM5N mount or the ZWO AM7 mount!
ZWO FF131 APO — Premium APO Performance for Demanding Astrophotographers
ZWO is expanding their lineup of standout telescopes with the newest addition of the APO Flat-Field Apochromatic Refractors! This 131mm quadruplet features the highly regarded four-element, fully air-spaced apochromatic optical design. An integrated flat-field design eliminates the need for an external field flattener and the additional ED glass dramatically improves color correction and image clarity. No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
A 983mm focal length and f/7.5 ratio ensures you strike the perfect balance between high-contrast deep-sky imaging and a highly portable, grab-and-go setup. Boasting a 44 mm image circle, this refractor is packed with features for easy astrophotography and visual astronomy. Compatible with ZWO ASI and DSLR/Mirrorless cameras, as well as 2”/1.25” diagonals. Including features like a 360° rotator, dual-speed focuser, quick-release rings, and a photographic extension with 2-inch filter threads.
ZWO FF131 is Packed with Thoughtful Features!
Dual-Speed Focusing
Equipped with a rigid 3-inch rack-and-pinion focuser, the FF131 APO offers precise control with a 1:10 coarse & fine focus adjustment mechanism. A built-in 360° rotator at the rear allows for smooth and accurate camera angle adjustments.
Built for All Astronomers
Highly versatile and seamlessly adapts to multiple imaging or visual setups. It provides native, plug-and-play compatibility with dedicated ZWO ASI, standard DSLR, or mirrorless cameras. Beyond deep-sky imaging, it easily converts into a high-end visual observation setup by supporting visual diagonals and eyepieces.
Flat-Field Design
The FF131 APO features a native flat-field optical design, eliminating the need for an additional field flattener.
No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
Four-Element Optical Design
The FF131 APO features a four-element, fully air-spaced apochromatic optical design. All four elements work together to deliver a flat imaging field without the need for an additional field flattener.
One ED (extra-low dispersion) glass element is incorporated to effectively reduce chromatic aberration, resulting in improved color correction and image clarity.
Photography Extension Tube
The FF131 APO is designed for seamless integration with modern imaging systems, and includes a standard four-section photographic extension tube with a 2-inch filter thread. Rear adapters in both M48x0.75 and M54x0.75 formats are also included, making it easy to connect a wide range of cameras, filters, and astrophotography accessories for a clean, flexible setup right out of the box.
Native Flat-Field Design
The FF131 APO features a native flat-field optical design, eliminating the need for an additional field flattener.
No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
Integrated Features for Ease
The FF131 APO features a retractable dew shield, reducing overall length for improved portability. Precision CNC machining and a high-quality painted finish, combined with an internal anti-reflection coating, help minimize stray light and enhance image contrast. The mounting rings are detachable, allowing for quick and easy setup or teardown of the telescope.
Specifications:
-
Effective Aperture: 131 mm (5.16 in)
-
Focal Length: 983 mm (38.70 in)
-
Focal Ratio: f/7.5
-
Objective Type: Four-element air-spaced APO (includes 1 ED element)
-
Image Circle: 44 mm (1.73 in)
-
Maximum Rear Connection Length (Focuser Retracted):
-
Imaging Mode:
-
73 mm (2.87 in) measured from M48×0.75 male thread
-
91 mm (3.58 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
131 mm (5.16 in) measured from 1.25 in eyepiece holder
-
142 mm (5.59 in) measured from 2 in eyepiece holder
-
-
-
Minimum Rear Connection Length (Focuser Retracted):
-
Imaging Mode:
-
42 mm (1.65 in) measured from M48×0.75 male thread
-
60 mm (2.36 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
100 mm (3.94 in) measured from 1.25 in eyepiece holder
-
111 mm (4.37 in) measured from 2 in eyepiece holder
-
-
-
Overall Length:
-
878 mm (34.57 in) with 1.25 in interface retracted
-
941 mm (37.05 in) with photography extension tube retracted
-
963 mm (37.91 in) with 1.25 in interface dew shield extended
-
1,026 mm (40.39 in) with photography extension tube dew shield extended
-
-
Telescope Body Weight: 7.9 kg (17.42 lb)
-
Standard Configuration Weight: 9.4 kg (20.72 lb) including handle, mounting rings, and dovetail plate
-
Rear Interfaces:
-
M78x1-55mm Extension Adapter
-
M78x1 to M54x0.75
-
M54x0.75 to M54x0.75
-
M54x0.75 to M48x0.75 (built-in M48x0.75 filter thread)
-
- Notes: *Focus can be achieved within a back focus range of 42–73 mm, measured from the M54–M48 interface shoulder
Important FF131 Diagrams
Optical Layout
Mechnical Diagram
Locking Screw Position Diagram
Star Field Map
Other Information
- Country of Manufacture: China
ZWO FF131 APO — Premium APO Performance for Demanding Astrophotographers
ZWO is expanding their lineup of standout telescopes with the newest addition of the APO Flat-Field Apochromatic Refractors! This 131mm quadruplet features the highly regarded four-element, fully air-spaced apochromatic optical design. An integrated flat-field design eliminates the need for an external field flattener and the additional ED glass dramatically improves color correction and image clarity. No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
A 983mm focal length and f/7.5 ratio ensures you strike the perfect balance between high-contrast deep-sky imaging and a highly portable, grab-and-go setup. Boasting a 44 mm image circle, this refractor is packed with features for easy astrophotography and visual astronomy. Compatible with ZWO ASI and DSLR/Mirrorless cameras, as well as 2”/1.25” diagonals. Including features like a 360° rotator, dual-speed focuser, quick-release rings, and a photographic extension with 2-inch filter threads.
ZWO FF131 is Packed with Thoughtful Features!
Dual-Speed Focusing
Equipped with a rigid 3-inch rack-and-pinion focuser, the FF131 APO offers precise control with a 1:10 coarse & fine focus adjustment mechanism. A built-in 360° rotator at the rear allows for smooth and accurate camera angle adjustments.
Built for All Astronomers
Highly versatile and seamlessly adapts to multiple imaging or visual setups. It provides native, plug-and-play compatibility with dedicated ZWO ASI, standard DSLR, or mirrorless cameras. Beyond deep-sky imaging, it easily converts into a high-end visual observation setup by supporting visual diagonals and eyepieces.
Flat-Field Design
The FF131 APO features a native flat-field optical design, eliminating the need for an additional field flattener.
No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
Four-Element Optical Design
The FF131 APO features a four-element, fully air-spaced apochromatic optical design. All four elements work together to deliver a flat imaging field without the need for an additional field flattener.
One ED (extra-low dispersion) glass element is incorporated to effectively reduce chromatic aberration, resulting in improved color correction and image clarity.
Photography Extension Tube
The FF131 APO is designed for seamless integration with modern imaging systems, and includes a standard four-section photographic extension tube with a 2-inch filter thread. Rear adapters in both M48x0.75 and M54x0.75 formats are also included, making it easy to connect a wide range of cameras, filters, and astrophotography accessories for a clean, flexible setup right out of the box.
Native Flat-Field Design
The FF131 APO features a native flat-field optical design, eliminating the need for an additional field flattener.
No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
Integrated Features for Ease
The FF131 APO features a retractable dew shield, reducing overall length for improved portability. Precision CNC machining and a high-quality painted finish, combined with an internal anti-reflection coating, help minimize stray light and enhance image contrast. The mounting rings are detachable, allowing for quick and easy setup or teardown of the telescope.
Specifications:
-
Effective Aperture: 131 mm (5.16 in)
-
Focal Length: 983 mm (38.70 in)
-
Focal Ratio: f/7.5
-
Objective Type: Four-element air-spaced APO (includes 1 ED element)
-
Image Circle: 44 mm (1.73 in)
-
Maximum Rear Connection Length (Focuser Retracted):
-
Imaging Mode:
-
73 mm (2.87 in) measured from M48×0.75 male thread
-
91 mm (3.58 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
131 mm (5.16 in) measured from 1.25 in eyepiece holder
-
142 mm (5.59 in) measured from 2 in eyepiece holder
-
-
-
Minimum Rear Connection Length (Focuser Retracted):
-
Imaging Mode:
-
42 mm (1.65 in) measured from M48×0.75 male thread
-
60 mm (2.36 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
100 mm (3.94 in) measured from 1.25 in eyepiece holder
-
111 mm (4.37 in) measured from 2 in eyepiece holder
-
-
-
Overall Length:
-
878 mm (34.57 in) with 1.25 in interface retracted
-
941 mm (37.05 in) with photography extension tube retracted
-
963 mm (37.91 in) with 1.25 in interface dew shield extended
-
1,026 mm (40.39 in) with photography extension tube dew shield extended
-
-
Telescope Body Weight: 7.9 kg (17.42 lb)
-
Standard Configuration Weight: 9.4 kg (20.72 lb) including handle, mounting rings, and dovetail plate
-
Rear Interfaces:
-
M78x1-55mm Extension Adapter
-
M78x1 to M54x0.75
-
M54x0.75 to M54x0.75
-
M54x0.75 to M48x0.75 (built-in M48x0.75 filter thread)
-
- Notes: *Focus can be achieved within a back focus range of 42–73 mm, measured from the M54–M48 interface shoulder
Important FF131 Diagrams
Optical Layout
Mechnical Diagram
Locking Screw Position Diagram
Star Field Map
| Manufacturer | ZWO Astronomy Cameras |
|---|---|
| Telescope Focal Length | 901 - 1000mm |
- 1x FF131 APO optical tube
- 1x Photographic extension tube
- 1x User manual
- 1x Inspection sheet
- 1x Warranty card
- 131mm f/7.5 flat-field APO refractor designed for high-resolution deep-sky imaging
- 983mm focal length offers impressive reach for galaxies, nebulae, star clusters, and smaller deep-sky targets
- Quadruplet optical design helps deliver well-corrected stars across the frame
- No separate field flattener required, making setup simpler and spacing less complicated
- Generous 44mm image circle provides coverage for full-frame and smaller astronomy cameras
- Large dual-speed focuser allows for precise manual focusing and fine adjustments
- Includes essential mounting and imaging accessories to help you get your setup built faster
- Save when you bundle the ZWO FF131 with either the ZWO AM5N mount or the ZWO AM7 mount!
ZWO FF131 APO — Premium APO Performance for Demanding Astrophotographers
ZWO is expanding their lineup of standout telescopes with the newest addition of the APO Flat-Field Apochromatic Refractors! This 131mm quadruplet features the highly regarded four-element, fully air-spaced apochromatic optical design. An integrated flat-field design eliminates the need for an external field flattener and the additional ED glass dramatically improves color correction and image clarity. No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
A 983mm focal length and f/7.5 ratio ensures you strike the perfect balance between high-contrast deep-sky imaging and a highly portable, grab-and-go setup. Boasting a 44 mm image circle, this refractor is packed with features for easy astrophotography and visual astronomy. Compatible with ZWO ASI and DSLR/Mirrorless cameras, as well as 2”/1.25” diagonals. Including features like a 360° rotator, dual-speed focuser, quick-release rings, and a photographic extension with 2-inch filter threads.
ZWO FF131 is Packed with Thoughtful Features!
Dual-Speed Focusing
Equipped with a rigid 3-inch rack-and-pinion focuser, the FF131 APO offers precise control with a 1:10 coarse & fine focus adjustment mechanism. A built-in 360° rotator at the rear allows for smooth and accurate camera angle adjustments.
Built for All Astronomers
Highly versatile and seamlessly adapts to multiple imaging or visual setups. It provides native, plug-and-play compatibility with dedicated ZWO ASI, standard DSLR, or mirrorless cameras. Beyond deep-sky imaging, it easily converts into a high-end visual observation setup by supporting visual diagonals and eyepieces.
Flat-Field Design
The FF131 APO features a native flat-field optical design, eliminating the need for an additional field flattener.
No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
Four-Element Optical Design
The FF131 APO features a four-element, fully air-spaced apochromatic optical design. All four elements work together to deliver a flat imaging field without the need for an additional field flattener.
One ED (extra-low dispersion) glass element is incorporated to effectively reduce chromatic aberration, resulting in improved color correction and image clarity.
Photography Extension Tube
The FF131 APO is designed for seamless integration with modern imaging systems, and includes a standard four-section photographic extension tube with a 2-inch filter thread. Rear adapters in both M48x0.75 and M54x0.75 formats are also included, making it easy to connect a wide range of cameras, filters, and astrophotography accessories for a clean, flexible setup right out of the box.
Native Flat-Field Design
The FF131 APO features a native flat-field optical design, eliminating the need for an additional field flattener.
No complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.
Integrated Features for Ease
The FF131 APO features a retractable dew shield, reducing overall length for improved portability. Precision CNC machining and a high-quality painted finish, combined with an internal anti-reflection coating, help minimize stray light and enhance image contrast. The mounting rings are detachable, allowing for quick and easy setup or teardown of the telescope.
Specifications:
-
Effective Aperture: 131 mm (5.16 in)
-
Focal Length: 983 mm (38.70 in)
-
Focal Ratio: f/7.5
-
Objective Type: Four-element air-spaced APO (includes 1 ED element)
-
Image Circle: 44 mm (1.73 in)
-
Maximum Rear Connection Length (Focuser Retracted):
-
Imaging Mode:
-
73 mm (2.87 in) measured from M48×0.75 male thread
-
91 mm (3.58 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
131 mm (5.16 in) measured from 1.25 in eyepiece holder
-
142 mm (5.59 in) measured from 2 in eyepiece holder
-
-
-
Minimum Rear Connection Length (Focuser Retracted):
-
Imaging Mode:
-
42 mm (1.65 in) measured from M48×0.75 male thread
-
60 mm (2.36 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
100 mm (3.94 in) measured from 1.25 in eyepiece holder
-
111 mm (4.37 in) measured from 2 in eyepiece holder
-
-
-
Overall Length:
-
878 mm (34.57 in) with 1.25 in interface retracted
-
941 mm (37.05 in) with photography extension tube retracted
-
963 mm (37.91 in) with 1.25 in interface dew shield extended
-
1,026 mm (40.39 in) with photography extension tube dew shield extended
-
-
Telescope Body Weight: 7.9 kg (17.42 lb)
-
Standard Configuration Weight: 9.4 kg (20.72 lb) including handle, mounting rings, and dovetail plate
-
Rear Interfaces:
-
M78x1-55mm Extension Adapter
-
M78x1 to M54x0.75
-
M54x0.75 to M54x0.75
-
M54x0.75 to M48x0.75 (built-in M48x0.75 filter thread)
-
- Notes: *Focus can be achieved within a back focus range of 42–73 mm, measured from the M54–M48 interface shoulder
Important FF131 Diagrams
Optical Layout
Mechnical Diagram
Locking Screw Position Diagram
Star Field Map
Other Information
- Country of Manufacture: China
| Manufacturer | ZWO Astronomy Cameras |
|---|---|
| Telescope Focal Length | 901 - 1000mm |
- 1x FF131 APO optical tube
- 1x Photographic extension tube
- 1x User manual
- 1x Inspection sheet
- 1x Warranty card
ZWO FF131 f/7.5 APO Quadruplet Refractor Telescope