The launch of Sharpstar 15028HNT, a fast-focal-ratio hyperbolic Newtonian astrograph, fills up the existing service gap in domestic market. Compared with the conventional parabolic mirror, the process of producing, manufacturing and testing hyperbolic mirror is much more intricate.
The astrograph comes second to no one considering its rather fast focal ratio. The telescope is wrapped with durable carbon fiber material, artistically enhancing its appearance while sharply decreasing its weight. Sharpstar 15028HNT adopts Pyrex-alike glass, enabling the mirror to reach a quite stable reflectivity.
Both primary and secondary mirrors wear enhanced aluminum coating, thus keeping a reflective rate at more than 96%. The one-piece X-shaped strut of the secondary mirror keeps a solid and unbreakable structure. 2.5" rack-and-pinion focuser has a stronger load capacity and can be smoothly adjusted.
The delicately pierced handle bar is completely made from CNC-manufactured aluminum, which can be used as a base for the attachment of other accessories. The new design of the telescope handle can aesthetically and mechanically cater to the demands of enthusiasts.
A three-element corrector is laid in the optical path, enabling the whole optical system to better achieve full-frame imaging and control the vignette. The standard 55mm back-focus and M48×0.75 thread tapped on the focuser thoroughly prepare the telescope for most stock imaging devices and make sure the item in the objective lens can be perfectly projected onto the focal plane.
Specifications
Type：150F2.8HNTAperture size：150mm
Focal length：420mm
Focal ratio：2.8
Primary mirror type：hyperbolic reflective mirror
Primary mirror material：PZ33(similar to Pyrex glass)
Corrector：three-element air-spaced lens structure
Minor axis：70mm
Image circle：44mm
Field of view：6 degree
Tube material：Carbon fiber
Tube outer diameter：195mm
Tube length：445mm
Net weight：4.45kg
Gross weight：5.95kg(including the dew cap, tube rings, handle and Losmandy-style dovetail plate)
Resolution：0.77 arc seconds
Focuser：2.5" with fine adjustment
Limiting visual magnitude：12.7
Back focus：55mm