Askar SQA55 55mm f/4.8 Quintuplet APO

Full-Frame f/4.8 Petzval Optics: A 44mm Flat Field

The SQA55 is built around a five-element Petzval optical design that corrects for field curvature internally, delivering a flat 44mm image circle sharp to the corners of a full-frame sensor. This integrated design, which includes one ED (Extra-low Dispersion) and one SD (Super ED) glass element, eliminates the need to purchase, space, and configure a separate field flattener, simplifying your imaging train.

The fast f/4.8 focal ratio allows you to gather significant signal in shorter exposure times, a critical advantage for mobile imaging setups. At a 264mm focal length, the SQA55 provides a sweeping field of view perfect for framing large targets like the Andromeda Galaxy (M31) or the North American Nebula (NGC 7000) in their entirety.

Dual-Purpose Design: 14 Blades from f/4.8 to f/22

Unlike most dedicated astrographs, the Askar SQA55 incorporates features for high-end terrestrial and wildlife photography. The manual aperture ring adjusts a 14-blade diaphragm, allowing you to stop the lens down from a wide-open f/4.8 all the way to f/22. This gives you precise control over depth of field for daytime subjects.

The 14-blade aperture produces exceptionally smooth, circular out-of-focus highlights (bokeh), adding an artistic quality to terrestrial images that fixed-aperture telescopes cannot achieve. Combined with a close focus distance of just 5m, the SQA55 becomes a versatile telephoto lens for both celestial and earthly subjects. Note that focusing is entirely manual, a trade-off for its robust optical performance.

Compact at 2.18kg: Built for Portability and Easy Integration

Engineered for imagers on the move, the SQA55 weighs only 1.84kg for the optical tube alone and 2.18kg with its handle and dovetail plate attached. Its compact length of 244mm (with the dew shield retracted) allows it to fit easily into carry-on luggage or a backpack, and it rides comfortably on even the most portable star trackers.

• Standard Connections: The rear of the scope terminates in M48x0.75 male threads, the standard for connecting most astronomy cameras and DSLR/mirrorless T-rings.
• 55mm Back Focus: The optical design is optimized for the industry-standard 55mm back focus distance, ensuring you can connect your camera via a standard T-ring and achieve perfect spacing without complex calculations.
• Filter Threads: The objective lens assembly includes M67 filter threads for attaching standard photographic filters, while the M48 rear adapter is also threaded for 2" astronomy filters.

Askar SQA55: Integrated Flat-Field vs. 2-Piece Optical Systems

Choosing an astrograph often means pairing a primary telescope with a separate, matched flattener or reducer. The SQA55's quintuplet Petzval design offers a compelling alternative by integrating the field-flattening elements directly into the main optics.

This approach provides a significant advantage in simplicity and reliability. There are no additional accessories to buy, no potential for tilt introduced by extra threaded connections, and no complex back focus calculations to perform. The SQA55 is a complete, flat-field imaging system right out of its included military-grade waterproof case.