Sky-Watcher HAC125DX MiniGraph EQ-AL55i Pro

Designed for fast wide-field astrophotography, the Sky-Watcher HAC125DX MiniGraph combines a 125 mm Honders Advanced Catadioptric astrograph with the EQ-AL55i Pro SynScan Wi-Fi GoTo equatorial mount.

With a focal length of only 250 mm and an extremely fast f/2 focal ratio, the HAC125DX is designed to collect large amounts of imaging data rapidly. Its optical system combines refractive and reflective surfaces within a compact catadioptric design.

The optical tube measures only 40 cm in length and weighs 3.82 kg. Its 16 mm image circle is particularly suitable for compact cameras using sensors such as the IMX533 and IMX585, with a stated maximum imaging camera weight of 300 g.

The HAC125DX features a rear focusing system operating on the primary mirror. This allows a wider range of cameras to be used than with the original HAC125 and makes focusing easier while the telescope is in use.

Combined with the EQ-AL55i Pro SynScan mount, the system provides a complete and portable astrophotography configuration. The mount can be controlled wirelessly from a smartphone or tablet through its integrated Wi-Fi module and the free SynScan Pro app for iOS and Android.

The SynScan database contains more than 10,000 celestial objects, and the mount can be used at all latitudes. A built-in illuminated polar scope assists with accurate polar alignment.

Honders Advanced Catadioptric Design

The HAC125DX uses a Honders Advanced Catadioptric optical design.

This hybrid configuration combines refractive and reflective optical surfaces to create a particularly compact and fast imaging system.

Its 125 mm aperture and 250 mm focal length provide an f/2 focal ratio.

Extremely Fast f/2 Focal Ratio

The f/2 focal ratio is one of the defining characteristics of the HAC125DX.

This speed allows more imaging data to be collected in less time than with a slower optical system.

The product description states that it can capture images five times faster than a standard f/4.9 optic and that this speed can remove the need for autoguiding.

125 mm Aperture and 250 mm Focal Length

The telescope has a 125 mm aperture.

Its very short 250 mm focal length provides a wide field suitable for imaging large celestial regions and extended objects.

Mangin Mirror and Optical Coatings

The optical system uses a Mangin-type mirror.

The mirror features Radiant Aluminum Quartz RAQ coating.

The corrector features HTMC coating.

16 mm Image Circle

The HAC125DX provides a 16 mm image circle.

This is particularly suited to compact astronomical cameras using sensors such as the IMX533 and IMX585.

The stated maximum imaging camera weight is 300 g.

Suitable for Beginners and Advanced Imagers

Despite its specialised imaging design, the HAC125DX is described as a platform suitable for both beginners and advanced imagers.

Its compact format, f/2 optics and Wi-Fi GoTo mount make it particularly suited to portable astrophotography configurations.

Rear Primary Mirror Focusing

The HAC125DX features a rear helical focusing system operating directly on the primary mirror.

This replaces the focusing arrangement used on the original HAC125 and allows a wider range of cameras to be used.

It also makes focusing easier while the telescope is in operation.

Collimatable Primary Mirror

The primary mirror cell is collimatable.

Optical alignment can therefore be adjusted when required.

Tube Rings and 45 mm Dovetail

The optical tube is supplied with mounting rings.

A 45 mm dovetail bar provides the mounting interface.

Dual Finderscope Brackets

Two finderscope brackets are fitted to the optical tube.

They allow compatible accessories to be installed according to the imaging configuration.

1.25-Inch and M42 x 0.75 Connections

The HAC125DX uses a 1.25-inch format.

A 1.25-inch adapter and an M42 x 0.75 adapter are included.

A dew shield is also supplied.

EQ-AL55i Pro SynScan Equatorial Mount

The EQ-AL55i Pro SynScan is a computerised Wi-Fi GoTo equatorial mount.

It can be controlled from a mobile device using the free SynScan Pro app for iOS and Android.

A SynScan hand controller can also be used but is available separately.

SynScan Database with More Than 10,000 Objects

The SynScan app provides access to a database containing more than 10,000 celestial objects.

It includes the Messier, NGC, IC and Caldwell catalogues, named deep-sky objects, named stars, double stars and Solar System objects.

When used with third-party planetarium software, the number of accessible objects is not limited by the SynScan database.

Alignment Methods

The SynScan app includes Brightest Star Alignment and North-Level Alignment.

Built-In Illuminated Polar Scope

The mount incorporates an illuminated polar scope.

It assists with accurate polar alignment of the equatorial mount.

All-Latitude Operation

The EQ-AL55i Pro can be used at all latitudes.

Mount Interfaces

The mount provides interfaces for:

• USB-C
• Autoguider
• Optional SynScan hand controller
• SNAP DSLR shutter control

The SNAP shutter control can be programmed through the SynScan Pro app.

1.75-Inch Stainless-Steel Tripod

The mount is supplied with a 1.75-inch diameter stainless-steel tripod.

An accessory tray is also included.

Power Requirement

The mount requires an external 12 V DC / 2 A centre-positive power supply.

Optical Tube Technical Specifications

• Manufacturer : Sky-Watcher
• Model : HAC125DX MiniGraph
• Type : Catadioptric astrograph
• Optical design : Honders Advanced Catadioptric
• Aperture : 125 mm
• Focal length : 250 mm
• Focal ratio : f/2
• Mirror type : Mangin
• Mirror coating : Radiant Aluminum Quartz RAQ
• Corrector coating : HTMC
• Image circle : 16 mm
• Secondary obstruction : 53 mm
• Primary mirror cell : Collimatable
• Focusing : Rear primary mirror helical focuser
• Maximum stated imaging camera weight : 300 g
• Format : 1.25 inch
• Adapter : 1.25 inch
• Adapter : M42 x 0.75
• Finderscope brackets : 2
• Tube rings : Included
• Dovetail bar : 45 mm
• Length : 40 cm
• Weight : 3.82 kg
• Dew shield : Included

Mount Technical Specifications

• Model : EQ-AL55i Pro SynScan
• Type : Computerised GoTo equatorial mount
• Wireless connection : Built-in Wi-Fi
• Control : SynScan Pro app for iOS and Android
• SynScan hand controller : Available separately
• SynScan database : More than 10,000 objects
• Deep-sky objects : 10,759
• Named stars : 305
• Double stars : 55
• Solar System objects : 7 planets, Sun and Moon
• Alignment methods : Brightest Star Alignment and North-Level Alignment
• Latitude use : All latitudes
• Polar scope : Built-in and illuminated
• Interface : USB-C
• Autoguider interface : Yes
• SynScan hand controller interface : Yes
• SNAP shutter control : Yes
• Tripod : Stainless steel
• Tripod diameter : 1.75 inch
• Accessory tray : Included
• Power requirement : 12 V DC / 2 A
• Polarity : Centre positive

Package Contents

• Sky-Watcher HAC125DX MiniGraph astrograph
• Tube rings
• 45 mm dovetail bar
• 1.25-inch adapter
• M42 x 0.75 adapter
• Dew shield
• EQ-AL55i Pro SynScan Wi-Fi GoTo equatorial mount
• 1.75-inch stainless-steel tripod
• Accessory tray

Not Included

• Imaging camera
• SynScan hand controller
• External 12 V DC / 2 A power supply