Astronomy Specialist



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The Sharpstar 150HNT is an astrograph with the ultra fast focal ratio of f/2.8 and a focal length of 420mm. Different from the Newton optical design, this telescope installs a hyperbolic primary mirror, a large 70mm secondary mirror and a 3 elements corrector to be placed before the focal plane. The optical design delivers a 44mm fully illuminated and corrected image circle for large sensors such as the full frame (24x36mm).

The mirror is made of H-PZ33 borosilicate glass with a similar low expansion thermal coefficient of the Pyrex. The enhanced aluminum mirror coating ensures a reflectivity over 96%. The large 70mm secondary mirror is rigidly kept in place by the monopiece secondary mirror spider that does not bend or twist.

The large rack and pinion 2.5" focuser can be rotated 360°and it has a reduction gear of 1:10 for precise focusing. The focuser is compatible with the ZWO EAF electronic focuser bracket.

All the lenses used in the corrector are fully multi-coated and the tube is internally blackened to reduce reflections and absorb stray light.

The tube is made of carbon fiber, the rack and pinion focusing mechanism of brass and the mechanical components are engineered to provide the best rigidity, performance and durability.


This telescope works at its best with its own focal reducer and corrector delivering a fully corrected field of view for the full frame sensors. The CCD inspector results shows that across the entire full frame this telescope produces a "curvature" of only 18.8%. That means at the corner of a full frame sensor, stars are only 18.8% larger than in the center. For more information about CCD Inspector, please read this article in the Testar blog.

CCD Inspector results with SharpStar 150 HNT.

Vignetting SharpStar 150 HNT

The maximum vignetting for the full frame is less than 20% at the corner of the sensor.




Optical design

Hyperbolic reflector with integrated corrector

Objective diameter

150 mm

Focal length

420 mm

Focal ratio


Secondary mirror 

70 mm (minor axis)



Resolving power

0.80 arc second

Stellar limiting magnitude


Max. magnification

375 x

Light gathering power

459 times the human eye

Mount attachment

Losmandy style bar (200 mm)


Rack & pinion, dual speed (10:1) 2.5" diameter

Camera connection

M48 x 0.75 male

Corrector distance

55 mm

Tube weight

5.95 kg (including tube rings and dovetail bar)

Tube length

445 mm

Tube diameter

195 mm

Tube material

Carbon fiber





  • SharpStar 150 HNT f/2.8
  • 196mm tube rings
  • 200mm Losmandy style dovetail bar
  • Handle on the rings
  • Adapter to 2" and 1.25"
  • Foam-lined aluminium case



M31 - Sharpstar 150 F/2.8 Astrograph



NGC6726 - Sharpstar 150 F/2.8 Astrograph - © Davide Mancini


M8 Lagoon Nebula & M20 Trifid Nebula - Sharpstar 150 2.8HNT Astrograph 

M8 & M20 - Sharpstar 150 F/2.8 Astrograph - © Davide Mancini


The Helix Nebula - Sharpstar 150 2.8HNT Astrograph

NGC7293 - Sharpstar 150 F/2.8 Astrograph - © Davide Mancini

Customer Reviews

Based on 1 review
Manuel Shaw
Sharpstar 150 response

Pleas resend your response to my review from 9/16/21.

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