Sky-Watcher HAC125DX Monograph – Ultra-Compact f/2 Mini Astrograph
SKU: S11250
The Sky-Watcher HAC125DX Monograph is a revolutionary evolution in portable astrographs—delivering extraordinary speed, precision, and portability in an 8.4-pound optical tube that fits in the palm of your hand. Designed around the rare and elegant Honders Advanced Catadioptric (HAC) optical system, the HAC125DX combines cutting-edge hybrid optics with practical mechanical refinements for astrophotographers seeking high-quality images without the bulk or fuss of traditional gear.
Ultra-Fast, Ultra-Compact
At an incredible f/2 focal ratio, the HAC125DX is one of the fastest production astrographs in existence. This 250mm focal length optic captures more photons per second than conventional small refractors or Ritchey-Chrétien systems, allowing you to achieve deep exposures in a fraction of the time. That translates to shorter imaging sessions, less stress on your tracking accuracy, and quicker setup-and-go when your observing window is short.
With a total length of just 15.7 inches and a lightweight aluminum tube, the HAC125DX is the ideal companion for portable equatorial mounts. Its 5-inch (125mm) aperture delivers impressive light-gathering power for its size—collecting 56% more light than a 100mm scope—while the compact build allows it to ride on modest tracking platforms with ease.
Honders Optical Design: Pure Imaging Efficiency
The Honders optical system is a rare breed in the telescope world—combining a Mangin mirror with carefully engineered refractive corrector elements to produce pinpoint stars and flat-field performance in an incredibly short tube. The result is a diffraction-limited system with minimal chromatic aberration and tight control of off-axis coma, perfect for wide-field astrophotography.
This redesigned DX version introduces rear primary mirror focusing—a welcome upgrade from the original HAC125—improving compatibility with a wide range of imaging setups and making precise focusing easier when the telescope is mounted.
The optical path features Sky-Watcher’s proprietary Radiant Aluminum Quartz (RAQ™) coatings, offering 94% reflectivity for optimal throughput. All corrector lenses are treated with High Transmission Multi-Coatings (HTMC™) to ensure maximum clarity and contrast.
Built for Imaging, Engineered for Practicality
The HAC125DX provides a 16mm image circle, making it an excellent match for popular imaging sensors like the IMX533 and IMX585. Whether you’re capturing nebulae, dense star fields, or sweeping wide-field mosaics, this astrograph delivers rich, sharp results across the field. Though the image circle is not full-frame, it's well suited for many current CMOS astronomy cameras.
Its integrated clamshell ring assembly includes a Vixen-style dovetail for compatibility with a wide range of mounts and saddles. Dual finder scope brackets provide flexibility for mounting guide scopes, electronic focusers, or other accessories. Camera connectivity is streamlined thanks to the included 1.25" adapter and M42x0.75 thread adapter, ensuring compatibility with many astronomy cameras right out of the box.
Despite its performance-focused design, the HAC125DX doesn’t skip on durability or handling. The precision-machined optical tube and rugged finish make this a travel-friendly scope you won’t hesitate to bring on the road—or into the field.
Summary of Features:
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125mm aperture with f/2 focal ratio (250mm focal length)
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Honders Advanced Catadioptric optical design with Mangin mirror
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Radiant Aluminum Quartz (RAQ™) mirror coatings, 94% reflectivity
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High Transmission Multi-Coatings (HTMC™) on corrector elements
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16mm image circle optimized for modern CMOS sensors (e.g., IMX533, IMX585)
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Lightweight 8.4 lbs tube, only 15.7 inches long
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Collimatable primary mirror cell with rear focuser
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Clamshell rings with V-style dovetail and dual finder brackets
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Included adapters: 1.25" visual back and M42x0.75 camera thread
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Ideal for wide-field imaging, travel astrophotography, and ultra-fast acquisition
The Astrograph Redefined
The Sky-Watcher HAC125DX is not just another small imaging scope—it’s a whole new category. It brings the performance of advanced astrographs into a form factor that fits your carry-on luggage. For the astrophotographer who values speed, quality, and true portability, the HAC125DX is a no-compromise solution.
Take it under dark skies, pair it with your favorite camera, and discover just how far a 5-inch mini astrograph can take your imaging journey.
