Sky-Watcher EQ8-RH Pro without Tripod

The EQ8-RH mount by Sky-Watcher represents a significant improvement over their previous models and is currently the most powerful mount available from the company. It has been specifically designed to handle a load capacity of up to 50 kilograms, making it suitable for mounting and accurately guiding large astrographs with diameters of up to 16 inches. These capabilities were once exclusive to the most prestigious equatorial mounts found in renowned observatories worldwide.

One of the key considerations for professional astrophotography mounts is precision tracking. The EQ8-RH achieves this by incorporating top-of-the-line components available in the market. It utilizes hybrid stepper motors that drive the worm gears of the declination and right ascension axes through intermediate belt gears. This configuration allows for optimal utilization of the motors' impressive resolving power, boasting a step size of 0.9°, while effectively eliminating vibrations.

The standout feature that sets the EQ8-RH apart from its predecessor, the EQ8R, is the addition of a precise encoder on the right ascension axis. Developed by Reinshaw, a company renowned for its cutting-edge solutions, this encoder system ensures impeccable tracking accuracy. It is worth noting that Reinshaw's encoders are utilized in various high-precision applications, including robots used in neurosurgical operations. With the encoder in place, both management and correction of periodic errors can be performed with surgical precision.

Included in the package is the advanced SynScan V5 controller, a well-known controller used in top-tier mounts such as the EQ6 and HEQ5. This controller enables users to access advanced tracking and correction functions, as well as the GOTO system. The extensive database contained within the SynScan V5 controller encompasses over 42,000 celestial objects, enhancing the overall experience for astronomers.

Key Features of the Sky-Watcher EQ8-RH Mount:

Hybrid stepper motors providing precise drive for declination and right ascension axes via a vibration-reducing intermediate belt transmission.

Ultra-precise Reinshaw encoder integrated into the right ascension axis, ensuring flawless tracking accuracy.

Control of the mount facilitated by the SynScan V5 controller, included in the set, featuring a comprehensive database of celestial objects.

Permanent periodic error control (PPEC) based on direct reading of the worm gear position.

Technical Specifications:

• Power Supply: 11 - 16 V, 3 A
• Mount Weight: 25.8 kg
• Counterweight Axle Weight: 2.6 kg
• Counterweight Weight: 2 x 10 kg
• Counterweight Axle Diameter: 31.5 mm
• Mounting Capacity: 50 kg
• Optical Tube Mounting: Losmandy
• Hand Controller: SynScan V5 Remote Control
• Right Ascension Gear: Worm Gear, 435:1 Ratio
• Declination Gear: Worm Gear, 435:1 Ratio
• Intermediate Gear: Belt in the Declination and Right Ascension Axes
• Height Adjustment: 10 - 65°
• Horizontal Adjustment: ± 10°
• Polar Finder: Optional, External
• Polar Axis Alignment: Programmatically or with the aid of the polar finder
• Encoder: Reinshaw Encoder on the Right Ascension Axis
• Encoder Resolution: 11,840,000 Pulses/Revolution, 0.11"
• Periodic Error Correction: Permanent (PPEC), 200 segments
• Home Position: Reset on Power Up
• Right Ascension Axis Limit: Mechanical
• Output Connectors: RJ10, RJ12 (ST-4), RJ45, 3 x 2.1 mm Power Plug, 4 x USB 3.0
• Input Connectors: USB-B, RJ10, RJ12 (ST-4), RJ45, 2.1 mm Power Plug
• SLR Shutter Control: Yes, Snap Socket
• Motors: Hybrid Stepper Motors, 0.9°/Step, 64 Microsteps
• Stepper Motor Resolution: 44,544,000 Pulses/Revolution, 0.03"
• Tracking Accuracy: 0.11"
• Guiding Accuracy: Less than 5' RMS
• Tracking Speeds: Star, Star + PEC, Solar, Lunar
• Autoguiding Speeds: 0.125x, 0.25x, 0.5x, 0.75x, 1x
• Maximum Travel Speed: 3.7°/s
• Tracking Modes: EQ Mode
• Surface Finish: Anodized, Black

Kit Components:

• Sky-Watcher EQ8-RH Mount Head
• SynScan V5 Controller
• Controller Cable
• Power Cable with Cigarette Lighter Plug
• Cable for Controlling Canon SLR Shutter
• Counterweight Axle
• Counterweights

Warranty:

24 months

Note on EQ8, EQ8-R, EQ8-RH Versions:

The EQ8 serves as the base model, followed by the improved versions EQ8-R and EQ8-RH, collectively referred to as the "R" series, as they share common manuals. The key distinction of the "R" series lies in the Cable Management System, which incorporates a built-in USB hub and power hub within the mount. This design allows most of the cables to be routed inside the mount housing, minimizing the risk of damage and facilitating easier replacement.

Moving on, the EQ8 featured two encoders, one in the declination axis and one in the right ascension axis. These encoders supported the Freedom Find function, which allowed users to manually adjust the mount without losing its alignment. According to the EQ8 manual, "The EQ8 mount is equipped with auxiliary encoders on both the RA axis and Dec. axis. Therefore, the mount can keep tracking its current position even when a user unlocks the clutches and rotates the mount in the RA axis and Dec. axis manually. With this feature, a user can manually operate the mount anytime without worrying about losing the mount's alignment status. When the user wants to operate the mount with the SynScan hand control again, no alignment is required, and all that is needed is to re-lock the clutches."

Regarding the R series, the following differences are observed. The EQ8-R model lacks any encoders, while the EQ8-RH incorporates a Reinshaw encoder on the right ascension axis. Unlike the Freedom Find function, the Reinshaw encoder in the EQ8-RH focuses on minimizing mechanical periodic errors during astrophotography tracking. The EQ8-RH is equipped with a Renishaw's high-resolution incremental encoder on its RA axis. This encoder aids in reducing or eliminating the influence of mechanical periodic errors while tracking celestial objects for astrophotography.

Another distinction lies in the use of a belt-driven intermediate gear. The EQ8 only had one belt gear on the right ascension axis to limit backlash, while the EQ8-R and EQ8-RH feature belt-driven systems on both axes. This implementation results in minimal backlash and significantly reduces periodic errors, ensuring smoother and more precise tracking.

In summary:

• EQ8: Original version with two encoders, Freedom Find function, and a single belt gear.
• EQ8-R: Improved version with Cable Management System, no encoders, and dual belt-driven transmissions.
• EQ8-RH: Enhanced version with Cable Management System, Reinshaw encoder, and dual belt-driven transmissions.

References:

[1] Sky-Watcher EQ8-RH Mount Head Only with Counterweights - Sky-Watcher USA

[2] Sky-Watcher EQ8-RH Review - Phil Hart

[3] Sky-Watcher EQ8 Manual

[4] Sky-Watcher EQ8-R V2 User Manual

[5] EQ8 GoTo Mount - Sky-Watcher Australia

[6] Sky-Watcher EQ8-RH Mount Head Only with Counterweights - Sky-Watcher USA