SharpStar 130mm f/2.8 HNT Hyperbolic Newtonian Astrograph

Sharpstar takes the initiative in launching the very first 150mm hyperbolic Newtonian reflective telescope with an extremely-fast focal ratio of f/2.8(15028HNT). It has garnered a quite large following since its advent. Not indulging in this great achievement, Sharpstar keeps the creativity and dynamism, introducing 13028HNT to our customers, which has a same focal ratio but a slightly smaller aperture size.

13028HNT, with a hyperbolic primary mirror, produces round and sharp stars within the full-frame and supports 44mm image circle. Compared with the focal ratio of f/4, 13028HNT can attain the same image quality while save almost half of the exposure time. Besides, due to its compact and concise design of the telescope tube, it will certainly create a stir again in the market.

The primary mirror is made of Pyrex-alike glass PZ33. The thermal expansion coefficient is smaller than ordinary glass. The dielectric multilayer coating makes the primary mirror obtain a highly reflective ability up to 97%. The minor axis of the secondary mirror is 65mm, enabling sufficient illumination for full-frame imaging. It’s worth mentioning that, the corrector is renovated to a two-refractive-lens set, one of which is an ED glass, aiming to simplify the optical system while enhancing the power in aberration correction.

The telescope tube is totally made of high-end carbon fiber material, so the weight of the telescope can greatly lessen and the overall appearance may artistically build up. All the component parts are from CNC constructed metals. The pair of tube rings feature pierced design. It may increase the production cost, but will absolutely offer extraordinary customer experience because of its lightweight and detail-oriented design concept.

The focuser is a 2.5″ rack-and-pinion device. It’s equipped with coarse as well as fine adjustment hand knobs to further improve the focusing precision. The focuser is tapped with M63 thread which can be switched into a more general M48×0.75 thread with a proper adapter ring(included). Thus the users may have a wider range of options in connecting other astronomy accessories to the focuser. The back-focus is standard 55mm(starting from the base of the mounting thread on the adapter ring’s housing), which is user-friendly for newcomers.

A versatile handle and a standard Vixen-style dovetail plate are also included in the 13028HNT package, which may be of convenience for users to attach other potential accessories and to place the telescope on various equatorial mounts.

Aperture：130mm
Focal length of primary mirror：364mm
Focal ratio of primary mirror：f/2.8
Primary mirror type：Hyperbolic reflective mirror
Primary mirror material：PZ33（similar to Pyrex glass）
Corrector：two-element air-spaced refractive lenses（including one ED glass）
Minor axis of secondary mirror：65mm
Image circle：44mm
Field of view：6.9 degree
Main tube material：High-end carbon fiber
Main tube outer diameter：174mm
Main tube length：394mm
Net weight：3.2kg
Gross weight：4.3kg（including protective cap, tube rings, handle and Losmandy-style dovetail plate）
Resolution：0.89 arc second
Focuser：2.5″ with fine-adjustment
Limiting visual magnitude：12.3
Back-focus：55mm