ZWO FF90 APO Flat-Field Apochromatic Refractor

The ZWO FF90 APO is a premium flat-field apochromatic refractor designed for astrophotography and visual observation. Featuring a 90mm aperture, 609mm focal length, and native flat-field optics, it delivers exceptional image quality while remaining lightweight and portable.

Native Flat-Field Optical Design

The FF90 APO features a four-element fully air-spaced apochromatic optical system that produces a naturally flat imaging field without requiring an additional field flattener.

ED Glass for Superior Colour Correction

An extra-low dispersion (ED) glass element effectively reduces chromatic aberration, improving colour fidelity, image sharpness, and overall contrast.

44mm Image Circle for Full-Frame Cameras

Designed to support full-frame sensors, the FF90 APO delivers excellent edge-to-edge sharpness and consistent image quality across the entire imaging field.

Lightweight and Portable Design

The optical tube weighs just 3.92kg, with a total system weight of approximately 4.52kg including rings and dovetail plate, making it ideal for both portable and permanent setups.

Precision Dual-Speed Focuser

A rigid 3-inch rack-and-pinion focuser features a 1:10 fine-focus mechanism for precise focusing. The integrated 360° rotator allows easy camera angle adjustments.

Retractable Dew Shield

The retractable dew shield improves portability while helping minimise stray light and dew formation during observing and imaging sessions.

Flexible Imaging Connectivity

The included photography extension tube features a 2-inch filter thread and includes M48×0.75 and M54×0.75 adapters for compatibility with a wide range of astrophotography accessories.

Quick-Release Mounting Rings

Detachable mounting rings allow fast installation, easy transport, and convenient setup.

Ideal For

Astrophotography, full-frame imaging, wide-field deep-sky photography, portable astronomy setups, and visual observation.