ZWO FF70 APO Refractor w/ AM3N Astrophotography Bundle

ZWO FF70-APO: A 70mm f/7 Quadruplet Optical System

The core of this bundle is the FF70 APO, a 70mm apochromatic refractor with a 490mm focal length. Its f/7 focal ratio and four-element optical design strike a critical balance between a wide field of view and the light-gathering power needed for deep-sky imaging. This configuration suits framing large targets like the Andromeda Galaxy (M31) or the North American Nebula (NGC 7000) on a full-frame sensor.

The quadruplet, air-spaced design incorporates one Extra-Low Dispersion (ED) glass element to minimize chromatic aberration. This ensures that bright stars are rendered as sharp points of light without distracting color fringing, producing images with high contrast and true-to-life color across the entire frame.

Native Flat-Field Design: A 44mm Image Circle with No Flattener Needed

One of the FF70 APO's most significant advantages is its self-flattening optical design, which delivers a 44mm corrected image circle without an external field flattener. This eliminates a common source of complexity in astrophotography, as there is no need to calculate and achieve a precise back focus distance for optical correction. The design fully illuminates full-frame sensors (36x24mm) and provides sharp, pinpoint stars from edge to edge.

Instead of a fixed back focus, the system provides a flexible focus range from 32.5mm to 82.5mm from the M48x0.75 thread. This generous range allows you to easily incorporate accessories like filter wheels and off-axis guiders into your imaging train. The included photography extension tube features both M48x0.75 and M54x0.75 threads, plus an integrated 2" filter thread for convenient filter placement.

Imaging Mechanics: A 2.4" R&P Focuser and 6.61 lb Portable Build

To support a modern imaging train, the FF70 APO is equipped with a rigid 2.4" rack-and-pinion focuser. A dual-speed 1:10 fine adjustment knob allows for the precise focus control essential for achieving sharp stars. The rear of the focuser incorporates a 360° rotator for exact framing of your target, a crucial feature for composition and creating mosaics.

Portability is a defining feature of this telescope. The optical tube alone weighs only 5.51 lbs., and the total weight with its handle, rings, and Vixen dovetail is just 6.61 lbs. Combined with a retracted length of 372.5mm, the FF70 APO is easy to transport and set up, making it well suited to traveling to dark-sky locations.

ZWO AM3N Mount: 17.64 lb Counterweight-Free Payload from a 9.04 lb Head

The ZWO AM3N mount uses a strain-wave gear system to carry a large payload from a light head. The mount head weighs only 9.04 lbs. yet supports a 17.64 lb. payload without requiring any counterweights. This creates a significant performance margin for the 6.61 lb. FF70 APO, leaving ample capacity for a camera, guide scope, and other accessories.

Each AM3N is factory-tested to ensure its periodic error is less than ±15 arcseconds, providing a smooth and accurate tracking foundation for long-exposure astrophotography. For even greater precision, the mount includes an ST4 autoguider port for use with a guide camera. The drive system's high torque and precision make balancing less critical, dramatically speeding up field setup.

AM3N Control Suite: Dual EQ/Alt-Az Modes via WiFi, USB, and ASIAIR

The AM3N offers a complete range of control options for any workflow. It can be operated in both equatorial mode for serious imaging and alt-azimuth mode for simple visual observing. Its latitude range of 0° to 90° ensures it can be polar aligned and used anywhere on Earth. Control methods include:

• Hand Controller: The included hand controller allows for immediate manual slewing and GoTo operation.
• Wireless Control: Integrated WiFi and Bluetooth allow you to control the mount wirelessly from a smartphone or tablet using the ASI Mount or SkyAtlas apps.
• PC Control: Full support for ASCOM and INDI drivers enables control from popular software like NINA, SGP, or ASIStudio via a USB connection.
• ASIAIR Integration: The mount is designed to work within the ZWO ecosystem, connecting directly to any ASIAIR model.

Support Structure: The 5.07 lb TC40 Tripod and 6.30" PE160 Pier Extension

A stable foundation is critical, and this bundle provides it without compromising portability. The included ZWO TC40 tripod is constructed from carbon fiber, weighing just 5.07 lbs. while supporting 110.23 lbs. Its adjustable height range of 18.5" to 31.49" allows you to achieve a low center of gravity for maximum stability on any terrain.

To prevent the telescope or camera from colliding with the tripod legs when pointed near the zenith, the bundle also includes the ZWO PE160 Pier Extension. This rigid aluminum extension adds 6.30" (160mm) of vertical clearance between the mount and tripod, enabling uninterrupted meridian flips and automated imaging sessions that track objects all night long.

ZWO FF70 APO vs. FF90 APO: Portability Against Aperture

Choosing between ZWO's flat-field refractors involves a direct trade-off between light-gathering power and portability. The FF90 APO offers a larger 90mm aperture, providing greater resolving power and collecting more light for fainter targets. However, this comes at the cost of increased size and weight, requiring a more substantial mount.

The FF70 APO's primary advantage is its extreme portability. At a fully equipped weight of 6.61 lbs., it is significantly lighter than its larger sibling and is well matched to compact harmonic drive mounts like the AM3N. If your priority is a lightweight, grab-and-go rig for wide-field imaging that is easy to travel with, the FF70 APO is the better fit.