ZWO FF90 f/6.8 APO Quadruplet Refractor Telescope
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- 90mm f/6.8 flat-field APO refractor designed for sharp, wide-field deep-sky imaging
- 609mm focal length offers a versatile image scale for nebulae, galaxies, star clusters, and more
- 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
- 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 FF90 with a complete ZWO mount kit — explore the deal!
ZWO FF90 APO — A Balanced Imaging Scope for Growing Astrophotographers
ZWO is expanding their lineup of standout telescopes with the newest addition of the APO Flat-Field Apochromatic Refractors! This 90mm 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 609mm focal length and f/6.8 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 FF90 is Packed with Thoughtful Features!
Flexible Connectivity
The ZWO FF90 APO features a 90 mm (3.54 in) aperture and 609 mm focal length (f/6.8), offering an excellent balance between portability and performance.
The optical tube weighs just 3.92 kg (8.64 lb), with a total system weight of 4.52 kg (9.96 lb) including mounting rings and dovetail plate.
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
With a 44 mm image circle, the FF90 APO fully supports full-frame sensors and a wide range of imaging setups.
It delivers sharp star fields with excellent edge-to-edge performance, ensuring consistent image quality across the entire frame.
Four-Element Optical Design
The FF90 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 FF90 APO includes a photography extension tube with a 2-inch filter thread, along with rear adapters in M48x0.75 and M54x0.75 standards. This allows for easy integration with a wide range of imaging accessories.
Native Flat-Field Design
The FF90 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.
Convenient Design
Equipped with a rigid 3-inch rack-and-pinion focuser, the FF90 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.
Integrated Features for Ease
The FF90 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: 90 mm (3.54 in)
-
Focal Length: 609 mm (23.98 in)
-
Focal Ratio: f/6.8
-
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:
-
75 mm (2.95 in) measured from M48×0.75 male thread
-
93 mm (3.66 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
112 mm (4.41 in) measured from 1.25 in eyepiece holder
-
122 mm (4.80 in) measured from 2 in eyepiece holder
-
-
-
Overall Length:
-
513 mm (20.20 in) with 1.25 in interface retracted
-
550 mm (21.65 in) with photography extension tube retracted
-
599 mm (23.58 in) with 1.25 in interface dew shield extended
-
636 mm (25.04 in) with photography extension tube dew shield extended
-
-
Telescope Body Weight: 3.92 kg (8.64 lb)
-
Standard Configuration Weight: 4.52 kg (9.96 lb) including handle, mounting rings, and dovetail plate
-
Rear Interfaces:
-
M64x1 to M54x0.75
-
M54×0.75 to M54x0.75
-
M54x0.75 to M48x0.75 (built-in M48x0.75 filter thread)
-
-
Interface of the Three-Stage Imaging Adapter: M48x0.75
-
Notes: Focus can be achieved within a back focus range of 45–75 mm, measured from the M54–M48 interface shoulder.
Important FF90 Diagrams
Optical Layout
Mechnical Diagram
Star Field Map
Other Information
- Country of Manufacture: China
ZWO FF90 APO — A Balanced Imaging Scope for Growing Astrophotographers
ZWO is expanding their lineup of standout telescopes with the newest addition of the APO Flat-Field Apochromatic Refractors! This 90mm 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 609mm focal length and f/6.8 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 FF90 is Packed with Thoughtful Features!
Flexible Connectivity
The ZWO FF90 APO features a 90 mm (3.54 in) aperture and 609 mm focal length (f/6.8), offering an excellent balance between portability and performance.
The optical tube weighs just 3.92 kg (8.64 lb), with a total system weight of 4.52 kg (9.96 lb) including mounting rings and dovetail plate.
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
With a 44 mm image circle, the FF90 APO fully supports full-frame sensors and a wide range of imaging setups.
It delivers sharp star fields with excellent edge-to-edge performance, ensuring consistent image quality across the entire frame.
Four-Element Optical Design
The FF90 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 FF90 APO includes a photography extension tube with a 2-inch filter thread, along with rear adapters in M48x0.75 and M54x0.75 standards. This allows for easy integration with a wide range of imaging accessories.
Native Flat-Field Design
The FF90 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.
Convenient Design
Equipped with a rigid 3-inch rack-and-pinion focuser, the FF90 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.
Integrated Features for Ease
The FF90 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: 90 mm (3.54 in)
-
Focal Length: 609 mm (23.98 in)
-
Focal Ratio: f/6.8
-
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:
-
75 mm (2.95 in) measured from M48×0.75 male thread
-
93 mm (3.66 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
112 mm (4.41 in) measured from 1.25 in eyepiece holder
-
122 mm (4.80 in) measured from 2 in eyepiece holder
-
-
-
Overall Length:
-
513 mm (20.20 in) with 1.25 in interface retracted
-
550 mm (21.65 in) with photography extension tube retracted
-
599 mm (23.58 in) with 1.25 in interface dew shield extended
-
636 mm (25.04 in) with photography extension tube dew shield extended
-
-
Telescope Body Weight: 3.92 kg (8.64 lb)
-
Standard Configuration Weight: 4.52 kg (9.96 lb) including handle, mounting rings, and dovetail plate
-
Rear Interfaces:
-
M64x1 to M54x0.75
-
M54×0.75 to M54x0.75
-
M54x0.75 to M48x0.75 (built-in M48x0.75 filter thread)
-
-
Interface of the Three-Stage Imaging Adapter: M48x0.75
-
Notes: Focus can be achieved within a back focus range of 45–75 mm, measured from the M54–M48 interface shoulder.
Important FF90 Diagrams
Optical Layout
Mechnical Diagram
Star Field Map
| Manufacturer | ZWO Astronomy Cameras |
|---|---|
| Telescope Focal Length | 601 - 700mm |
- 1x FF90 APO optical tube
- 1x Photographic extension tube
- 1x User manual
- 1x Inspection sheet
- 1x Warranty card
- 90mm f/6.8 flat-field APO refractor designed for sharp, wide-field deep-sky imaging
- 609mm focal length offers a versatile image scale for nebulae, galaxies, star clusters, and more
- 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
- 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 FF90 with a complete ZWO mount kit — explore the deal!
ZWO FF90 APO — A Balanced Imaging Scope for Growing Astrophotographers
ZWO is expanding their lineup of standout telescopes with the newest addition of the APO Flat-Field Apochromatic Refractors! This 90mm 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 609mm focal length and f/6.8 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 FF90 is Packed with Thoughtful Features!
Flexible Connectivity
The ZWO FF90 APO features a 90 mm (3.54 in) aperture and 609 mm focal length (f/6.8), offering an excellent balance between portability and performance.
The optical tube weighs just 3.92 kg (8.64 lb), with a total system weight of 4.52 kg (9.96 lb) including mounting rings and dovetail plate.
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
With a 44 mm image circle, the FF90 APO fully supports full-frame sensors and a wide range of imaging setups.
It delivers sharp star fields with excellent edge-to-edge performance, ensuring consistent image quality across the entire frame.
Four-Element Optical Design
The FF90 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 FF90 APO includes a photography extension tube with a 2-inch filter thread, along with rear adapters in M48x0.75 and M54x0.75 standards. This allows for easy integration with a wide range of imaging accessories.
Native Flat-Field Design
The FF90 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.
Convenient Design
Equipped with a rigid 3-inch rack-and-pinion focuser, the FF90 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.
Integrated Features for Ease
The FF90 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: 90 mm (3.54 in)
-
Focal Length: 609 mm (23.98 in)
-
Focal Ratio: f/6.8
-
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:
-
75 mm (2.95 in) measured from M48×0.75 male thread
-
93 mm (3.66 in) measured from M54×0.75 male thread
-
-
Observation Mode:
-
112 mm (4.41 in) measured from 1.25 in eyepiece holder
-
122 mm (4.80 in) measured from 2 in eyepiece holder
-
-
-
Overall Length:
-
513 mm (20.20 in) with 1.25 in interface retracted
-
550 mm (21.65 in) with photography extension tube retracted
-
599 mm (23.58 in) with 1.25 in interface dew shield extended
-
636 mm (25.04 in) with photography extension tube dew shield extended
-
-
Telescope Body Weight: 3.92 kg (8.64 lb)
-
Standard Configuration Weight: 4.52 kg (9.96 lb) including handle, mounting rings, and dovetail plate
-
Rear Interfaces:
-
M64x1 to M54x0.75
-
M54×0.75 to M54x0.75
-
M54x0.75 to M48x0.75 (built-in M48x0.75 filter thread)
-
-
Interface of the Three-Stage Imaging Adapter: M48x0.75
-
Notes: Focus can be achieved within a back focus range of 45–75 mm, measured from the M54–M48 interface shoulder.
Important FF90 Diagrams
Optical Layout
Mechnical Diagram
Star Field Map
Other Information
- Country of Manufacture: China
| Manufacturer | ZWO Astronomy Cameras |
|---|---|
| Telescope Focal Length | 601 - 700mm |
- 1x FF90 APO optical tube
- 1x Photographic extension tube
- 1x User manual
- 1x Inspection sheet
- 1x Warranty card
ZWO FF90 f/6.8 APO Quadruplet Refractor Telescope