ZWO FF110-APO 110mm Quadruplet Refractor F/7.0
- 90mm Aperture
- 766mm Focal Length (f/7)
- 4-Element Apochromatic Optics
- Integrated Field Flattener
- 3-inch Dual-Speed Focuser
- 14.9 lb. Optical Tube Weight
The ZWO FF110-APO combines a 4-element optical system with a 766mm focal length (f/7) to deliver a fully corrected image field without external flatteners. Its 90mm aperture gathers significant light for detailed deep-sky imaging, while the heavy-duty 3-inch rack-and-pinion focuser supports large camera packages without flexure. The complete optical tube assembly weighs 14.9 lb, requiring a stable equatorial mount for precise tracking.
This refractor's quadruplet optical design provides apochromatic color correction and a natively flat field, eliminating the need for a separate flattener. This simplifies your imaging train and removes the complexity of calculating back focus; as long as you can achieve focus, the starfield is sharp edge-to-edge. The 766mm focal length frames many popular deep-sky targets like the Horsehead Nebula (Barnard 33) and the core of the Andromeda Galaxy (M31) with room to spare on full-frame sensors.
To prevent image shift and flexure with heavy cameras and filter wheels, the FF110-APO is built with a robust 3-inch rack-and-pinion focuser. The dual-speed 1:10 fine adjustment knob allows you to achieve critical focus with precision, which is essential for resolving fine detail. This large-format focuser ensures the optical path is never vignetted, even with large full-frame camera sensors.
The primary distinction between the ZWO FF110-APO and its smaller sibling is between image scale and portability.
The FF110-APO includes essential hardware to get you mounted and imaging quickly, including a set of mounting rings and a standard Vixen-style dovetail plate. A key trade-off for its optical power is the 14.9 lb OTA weight. This requires an equatorial mount in the EQ6/CEM40 class or greater to ensure stable, unguided exposures and reliable tracking for long-exposure astrophotography.
Yes. With its 766mm focal length, the ZWO FF110-APO provides an excellent image scale for framing the Horsehead and Flame Nebula region, especially when paired with an APS-C or full-frame sensor. The flat-field optics will ensure that the prominent stars in the field, like Alnitak, remain sharp without needing a separate corrector.
For stable imaging, a mount with a payload capacity of at least 25-30 pounds is recommended to handle the 14.9 lb OTA plus the weight of your camera, guidescope, and other accessories. Mounts like the Sky-Watcher EQ6-R Pro, Celestron AVX (for lighter setups), or ZWO's own AM5 are appropriate choices.
No. The ZWO FF110-APO uses a 4-element Petzval-like optical design that has an integrated flattener. You do not need to purchase an additional flattener or calculate a specific back-focus distance, which simplifies the imaging setup significantly.
The telescope includes a photography extension tube that provides standard M48x0.75 and M54x0.75 male threads. You connect your camera using the appropriate T-ring and adapters for your specific camera model to attach to these threads.
The provided specification data lists the aperture for this model as 90mm. While the model number is "110," all performance characteristics described are based on the confirmed 90mm aperture and 766mm focal length from the official data sheet.
A 3-inch focuser provides two main benefits. First, its larger diameter prevents vignetting (darkening of the corners) on large, full-frame sensors. Second, its robust rack-and-pinion design provides higher load capacity, preventing sag or flex when using heavy imaging equipment like cooled cameras and filter wheels.
| SKU Number | ZWO-FF110-APO |
| Model | 110 mm APO Refractor |
| Series | ZWO Refractors |
| Optical Design | Apochromatic Refractor |
| Number of Elements | 4 (Quadruplet) |
| Aperture | 90mm (3.54") |
| Focal Length | 766 mm |
| Focal Ratio | f/7 |
| Focuser | 3" Dual-Speed Rack & Pinion |
| OTA Weight | 14.9 lb. |
| Mount Type | No Mount - OTA Only |
| Electronics | OTA Only - No Electronics |
ZWO 110 mm APO Refractor OTA
× 1
Mounting Rings
× 1 Set
Vixen Dovetail Plate
× 1
Findershoes
× 2
Photography Extension Tube
× 1
Warranty Card
× 1
Inspection Card
× 1
User Manual
× 1