Sharpstar 15028HNT-AL: Ultra-Fast Hyperbolic Newtonian Astrograph Fast f/2.8 Optical System – A hyperbolic Newtonian reflector with a 150mm aperture and an extremely fast f/2.8 focal ratio, ideal for deep-sky imaging. Full-Frame Imaging Capability – Supports a 44mm image circle, ensuring excellent star performance across full-frame sensors. High-Quality Primary Mirror – Made of PZ33 Pyrex-alike glass with a 97% dielectric multilayer reflective coating, reducing thermal expansion and enhancing image quality. Enhanced Secondary Mirror Structure – Features a 70mm minor-axis secondary mirror for full-frame illumination, with an integrated CNC-machined bracket for added stability and diffraction spike aesthetics. Advanced Triplet Corrector Lens – Integrated into the focuser with one ED glass element, improving aberration correction and sharpness. Precision Focuser with Camera Rotator – Dual-speed rack-and-pinion focuser with built-in triplet corrector, supporting up to 3kg payload, and features a rotator for flexible framing. Robust Mechanical Design – All-metal aluminum lens tube with CNC-machined tube rings, enlarged hand screws, and a Losmandy-style 200mm dovetail plate. Finder Scope Mounting – Comes with a finder base for additional accessories. Standard 55mm Back Focus – Optimized for astrophotography, ensuring compatibility with a wide range of imaging setups. The Sharpstar 15028HNT-AL is an ultra-fast, high-precision astrograph, perfect for astrophotographers seeking superior image quality, efficient light capture, and a robust design for deep-sky imaging. Specifications 15028HNT Aperture size 150mm Focal length 420mm Focal ratio f/2.8 Primary mirror type Hyperbolic reflective mirror Primary mirror material PZ33(similar to Pyrex glass) Corrector Three-element air-spaced refractive lenses(including one ED glass) Minor axis of secondary mirror 70mm Image circle 44mm Field of view 6 degree Main tube material Aluminum Main tube outer diameter 193mm Main tube length 443mm OTA weight 4.8kg Gross weight(including tube ring and dovetail plate) 6kg Resolution 0.77 arc second Limiting visual magnitude 12.7 Back-focus 55mm Product Size Diagram Please refer to the contents of the manual for specific optical axis alignment: SHARPSTAR 15028HNT Instruction Manual Electronic Focuser Assembly Diagram