Askar N210 - 210/714 mm f/3.4 Newtonian Astrograph - with optics test

Askar N210 - 210/714 mm f/3.4 Newtonian Astrograph - with optics test

Properties

The N210 features a large 210 mm aperture and a focal ratio of f/3.6. When used with the included 2-inch 0.95x coma corrector, the system focal ratio is optimized to f/3.4, which significantly shortens exposure times and achieves perfect compatibility with APS-C format for deep-sky imaging.



Larger aperture with approximately a 78% increase in light-gathering area

Compared with N160, the N210 delivers approximately 78% larger light-gathering area, bringing a substantial boost in light-gathering capability. Light-gathering area is a critical factor in deep-sky photography, greater light throughput captures more faint deep-sky signals, effectively boosting image SNR and detail resolution, producing cleaner, more transparent images.

At the core of the optical system, the primary mirror features a high-precision parabolic design. Relying on rigorous grinding and testing, it effectively eliminate spherical aberration. This ensures that star points across the entire frame remain uniform, solid, sharp, and transparent which perfectly meeting the stringent quality demands of deep-sky imaging.



Standard 2-inch 0.95x Coma Corrector

The included 2-inch 0.95x coma corrector features a triplet air-spaced design,effectively correcting coma aberrations and ensuring sharpness from the center to the edge of the frame, delivering sharp and clear images.

The corrector features a threaded locking design for a secure connection to the focuser, offering greater stability than traditional push-fit designs.



Primary and Secondary Mirror Glass Material

Both the primary and secondary mirrors are made of high-borosilicate glass, which has an extremely low coefficient of thermal expansion and strong adaptability to temperature changes. This effectively prevents mirror deformation or optical axis misalignment caused by temperature variations. The mirror surfaces are coated with enhanced aluminum for high reflectivity, ensuring bright, clear imaging with abundant fine details.



Primary Mirror Design

The primary mirror employs a dedicated surrounding support structure design that ensures even force distribution and outstanding structural rigidity, effectively improving support stability. This design is particularly optimised for scenarios such as meridian flips, maintaining optical stability even during large telescope position changes, providing reliable mechanical support for long-exposure imaging.

The primary mirror is equipped with three height adjustment knobs and three height locking knobs. The height adjustment knobs allow fine tuning of the primary mirror angle for precise collimation; the height locking knobs secure the primary mirror position after collimation, preventing any shift during subsequent use.



Secondary Mirror Design

The N210 features a newly upgraded, precision-machined one-piece secondary mirror bracket designed for large-aperture imaging. Its reinforced structure significantly enhances stability while maintaining a lightweight design - effectively reducing tube load. This balanced construction provides a rigid yet lightweight foundation, ensuring reliable support for long deep-sky exposures.

Four pre-drilled holes on the secondary mirror bracket allow users to easily install a rainproof cover via screw fixation, offering greater flexibility.

The secondary mirror has a minor axis of 71 mm and a major axis of 100 mm, providing unifrom and ample illumination for APS-C sensors, and ensuring uniform brightness across the entire frame from center to edge.

To suppress stray light and enhance contrast, the N210 features a black nylon-wrapped structure around the secondary mirror. This design slows temperature changes, reduces thermal shock, minimizes condensation risk, and ensures optical stability during long night sessions.

Three tilt adjustment screws are fitted on the bracket base, enabling fine angle adjustment of the secondary mirror. The mirror position can be flexibly adjusted according to shooting needs to further improve imaging accuracy.



Dual-Speed Rack-and-Pinion Focuser

The telescope is equipped with a dual-speed rack-and-pinion focuser, compatible with almost all brands of electronic focusers. The 25 mm focus travel provides ample room for achieving focus.

The focuser body can be rotated entirely, effectively preventing interference when attaching accessories such as an electronic focuser, improving accessory compatibility.

The focuser base equipped with angle adjustment screws and locking screws to ensure precise alignment between the focuser axis and the primary mirror optical axis.



Multi-Function Tube Rings and Dovetail Plate

The tube rings feature a clamshell opening design with large hand-tightened locking screws, that require no additional tools for installation or removal, making operation quick and convenient.

The top handle of the tube rings includes a multi-function finder base slot, which not only facilitates easy carrying but also provides additional mounting positions for other astronomy accessories.

The bottom dovetail plate is a standard Vixen-style dovetail, 400 mm in length, allowing direct connection to most commercially available mounts or tripods, offering excellent versatility and allowing quick setup without extra adapters.



Carbon Fiber Tube

N210 continues the classic red-and-black color scheme of the N series, simple and timeless. The tube is made of high-quality carbon fiber, balancing light weight with structural stability, significantly reducing overall weight while maintaining tube rigidity. The inner tube wall is lined with professional light-baffle felt to effectively suppress stray light.

Carbon fiber has an extremely low coefficient of thermal expansion, effectively resisting temperature variations and preventing tube deformation or focal shift caused by thermal expansion or contraction, ensuring imaging stability.

The side of the tube features a pre-drilled finder base, allowing you to mount a guide scope or other accessories as needed, further expanding observation capabilities and improving efficiency.



Features

Important notes to the picture:

1.The focuser base of the Askar N210 is locked at the factory. The base is equipped with six locking screws. If you need to rotate the focuser, be sure to loosen the locking screws before use to avoid mechanical damage.

2.This product has been collimated at the factory. In most cases, it is ready for use right out of the box without extra adjustment. However, due to various uncontrollable factors (e.g., shipping, handling, or other external impacts), slight misalignment may occur. If this happens, please fine-tune the primary mirror collimation to ensure observation and imaging accuracy.

 

Safety informations: PDF Download