Askar N160 f/3.6 Newtonian

160mm f/3.6 Optics: Parabolic Primary and 61mm Secondary

The core of the N160 is its high-precision 160mm parabolic primary mirror, which provides significant light-gathering capability for imaging faint deep-sky objects. The native optical system has a focal length of 576mm and a fast f/3.6 focal ratio. Both the primary and the 61mm minor-axis secondary mirror are made from high borosilicate glass, which has a very low coefficient of thermal expansion to maintain stability as temperatures change.

The mirrors feature an enhanced aluminum coating for high reflectivity, maximizing signal to your camera sensor. The 61mm minor-axis (86mm major-axis) secondary provides ample illumination coverage for APS-C sensors to ensure uniform brightness across the frame. The resulting 38.1% central obstruction is a typical trade-off for a fast, wide-field Newtonian designed for photographic use, prioritizing illumination over the slightly higher contrast favored by planetary observers.

0.95x Triplet Corrector: An f/3.4 System for a 28mm Image Circle

Included with the Askar N160 is a 0.95x coma corrector, an essential component for any fast Newtonian astrograph. This triplet air-spaced corrector transforms the optical system into an even faster f/3.4, 544mm focal length instrument, allowing you to collect more data in less time and reducing demands on your mount's tracking accuracy. It effectively corrects coma aberrations, and it is equipped with threaded connections for greater stability.

• APS-C Optimized: The corrector produces a flat, corrected 28mm image circle, making it a perfect match for cameras with APS-C format sensors.
• Standard Back Focus: It terminates in a standard M48x0.75 thread and requires a 55mm back focus distance from the thread shoulder to your camera sensor, simplifying integration with most astronomy cameras, filter wheels, and off-axis guiders.
• Precision Spacing: The package includes 0.1mm, 0.2mm, and 0.3mm shims, allowing you to fine-tune the 55mm spacing to achieve perfect correction, especially when accounting for the thickness of various filters in your imaging train.

25mm Travel Focuser: Dual-Speed, Rotatable, and Adjustable

The Askar N160 is equipped with a robust, dual-speed rack-and-pinion focuser with 25mm of travel, allowing for precise adjustments with both coarse and fine focus knobs. The focuser body is fully rotatable, a critical feature for framing your target without rotating the entire optical tube or camera assembly. This also prevents accessories like an electronic focuser from interfering with the mount or tube.

The focuser supports the installation of an electronic focuser. The focuser base also includes angle adjustment and locking screws, a key component of the telescope's collimation system. This allows you to precisely square the focuser's optical axis with the primary mirror, as part of collimation.

Carbon Fiber Construction: A 3.97kg OTA with a 5.2kg Gross Weight

The tube is made of high-quality carbon fiber, and a finder base on the side of the tube lets you mount a finder scope or other accessories. The tube rings have hand-tightened locking screws for tool-free installation and removal, and the top handle includes a multi-function finder base slot.

The carbon fiber construction keeps the optical tube assembly (OTA) weight to an impressive 3.97kg. Even when fully outfitted with the included tube rings, 230mm Vixen-style dovetail plate, multifunctional handle, and corrector, the total gross weight is only 5.2kg. Askar's 230mm Vixen-style dovetail has pre-drilled 1/4-inch and 3/8-inch threaded holes.

Precision Collimation for the Askar N160

Accurate alignment matters on a fast Newtonian, and the N160 can be collimated by the user. The user manual provides a detailed, step-by-step process for aligning every component in the optical train. The process begins with squaring the focuser axis using a printed calibration aid, to center the focuser axis.

Next, the secondary mirror is adjusted for height, rotation, and tilt to center it under the focuser and correctly aim it at the primary mirror. Finally, the primary mirror is adjusted with its three angle adjustment knobs and secured with three locking knobs. Askar's procedure does the coarse adjustment with an OCAL collimator, then the fine adjustment on a defocused star on a clear night with good seeing, until the star halo is concentric.