Askar SQA60 Pro F/4.6 Petzval Astrograph

The on-axis star diameters remain confined within an RMS radius of less than 1 µm, while at the edge of the corrected field, at 22 mm from the optical axis, the star diameters stay within an RMS radius of 2.1 µm.

The optical system features a sophisticated six-element (3-2-1) Petzval lens configuration with air spacing, balancing excellent optical performance with structural stability. The second and fourth elements are crafted from high-quality SD glass for effective chromatic aberration correction and enhanced sharpness. Furthermore, the fourth and fifth elements maintain the same clear aperture as the front lens, a rare feature in this category, ensuring bright, uniform illumination and an exceptionally flat field across a full-frame sensor.

This self-flattening integrated full-frame design eliminates the need for a separate flattener or complex back-focus calculations. Simply reach focus with a connection distance between 41 mm and 66 mm, and you are ready to shoot (55 mm is optimal).

The newly designed, single-piece tube rings feature a lightweight, hollowed-out central section. Equipped with enlarged locking knobs, they allow for quick, tool-free opening and closing.

The top carrying handle integrates a multifunctional finder scope dovetail slot for mounting various accessories.

The base is raised to increase clearance, minimizing the risk of collision with the mount during operation.

Additionally, a stepped structure inside the pair of tube rings visually indicates the correct installation orientation, with the stepped side facing toward the focuser end, to prevent incorrect assembly.

The standard 290 mm Vixen-style dovetail bar ensures quick and easy mounting. Integrated index markings provide a clear visual reference, making balance adjustments intuitive and precise.

The high-precision dual-speed rack-and-pinion focuser is compatible with most commercially available motor focusers. It features a 25 mm travel distance with a finely engraved scale on the drawtube. The CNC-machined drawtube incorporates internal baffle threads and an anti-reflective coating for superior stray-light control.

The Askar SQA60 Pro Petzval Astrograph is constructed entirely from CNC-machined components and features a professional fine-anodized finish.

Finder scope bases are located on both sides of the focuser, allowing users to swap the finder's position or mount additional accessories without having to disassemble anything.

A 360° rotator, featuring an engraved graduated scale, enables precise and repeatable framing angle adjustments. A large locking knob ensures a secure hold, even under heavy equipment loads.

The rear of the Askar SQA60 Pro Petzval Astrograph features a standard M48 adapter with an integrated 2" filter thread, ensuring broad compatibility with professional astronomy cameras.

The astrograph is also compatible with mirrorless and DSLR cameras for conventional photography.

The Askar SQA60 Pro Petzval Astrograph features an air-spaced six-element optical design, which includes 2 SD glass elements.

The image quality of the optical system can be evaluated by analyzing the point distribution in the spot diagram.

The Askar SQA60 Pro Petzval Astrograph features a central spot with an RMS radius of less than 1 µm at the center and less than 2.1 µm at the corners. In summary, its star pinpointness is excellent.

Relative Illumination (RI) represents the combined effect of light fall-off and corner vignetting of the lens, and the RI curve illustrates the variation in illuminance (%) across the image field on the sensor. Variations in illumination can negatively impact the final image. The vertical axis represents sample illumination intensity percentages, while the horizontal axis indicates the distance from the center of the frame to the edge. Even at the extreme edges of a full-frame sensor, the Askar SQA60 Pro Petzval Astrograph maintains an illumination level above 95%, keeping vignetting to an absolute minimum.