Sharpstar Optics 130mm f/2.8 Hyperbolic Newtonian Astrograph - 13028HNT-AL

The 13028HNT-AL is a hyperbolic Newtonian reflector with a 130mm aperture and a fast F2.8 focal ratio.

13028HNT-AL supports a 44mm full-frame image circle, and the star performance is great.

The primary mirror is made of Pyrex-alike glass PZ33. The thermal expansion coefficient is smaller than ordinary glass. The dielectric multilayer coating gives the primary mirror a highly reflective ability of up to 97%. The minor axis of the secondary mirror is 65mm, enabling sufficient illumination for full-frame imaging.

The corrector in the focuser adopts a doublet lens design, one of which is an ED glass, enhancing the power in aberration correction.

13028HNT-AL further enhances the structure stability of the optical axis of the primary mirror, and there are three sets of adjustment screws at the bottom of the lens tube for adjusting the angle of the primary mirror.

13028HNT-AL improves the bracket structure of the secondary mirror to make it more stable. The secondary mirror bracket is CNC machined， integrated manufacturing with no misalignment, which ensures beautiful diffraction spikes during astrophotography.

There is a finder base on the side of the lens tube, which provides additional mounting positions for finder scope or other astronomical accessories.

13028HNT-AL ‘s tube ring is a hollow design, sturdy and durable. Enlarged hand screws allow users to open and close the tube ring without additional tools.

13028HNT-AL's focuser is a dual-speed rack-and-pinion large rigid focuser, which ensures a 2cm focusing travel as much as possible within the structural limitations and can be compatible with most motorized focusers.

The focuser is designed with an enlarged handwheel, integrated camera rotator and locking screw, and a built-in doublet corrector. The structure of the focuser is very stable and can carry 3kg.

The back focus of 13028HNT-AL is standard 55mm (from the M48 thread).

Standard Vixen-style 290mm dovetail plate.

13028HNT-AL is all-metal, with an aluminum lens tube and CNC machined parts.

* The 13028HNT-AL focuser and rotator are shipped in a locked condition. Users should be sure to loosen the locking screws before initial use to avoid damage to the part.