Sky-Watcher EQ8-Rh Mount with Pier Tripod

A 50 kg Payload Capacity

It provides a 50 kg (110 lb) payload capacity, rated specifically for astrophotography and excluding the two included 10 kg counterweights. There is no list of compatible telescopes: add up the tube, camera, guide scope and accessories and compare the total with the rating.

The mount head weighs 25.8 kg (56.9 lb) and the steel pier tripod 29.4 kg (64.8 lb).

A 435:1 Worm Drive with a 0.11" Renishaw Encoder

The EQ8-Rh has a 435:1 worm drive transmission paired with 0.9° hybrid stepper motors. With 256 microsteps per step, this gives a drive resolution of approximately 0.03 arc-seconds.

It is available on the EQ8-RH only: the mount carries a Renishaw high-resolution incremental encoder on the Right Ascension axis. This component provides a resolution of approximately 0.11 arc-seconds (11,840,000 counts per revolution). This encoder helps reduce or eliminate the influence of mechanical periodic error while the mount tracks an object.

Counterweights and Balancing

The EQ8-Rh includes a 2.6 kg counterweight rod and two 10 kg counterweights. Balancing reduces stress on the motor drive system and ensures smooth, accurate operation.

Following the manual's procedure, you first balance the R.A. axis by loosening the R.A. clutch and rotating the axis until the counterweight rod is parallel to the ground. You then slide the counterweights along the rod until the mount remains stationary without support. After tightening the R.A. clutch, you balance the Declination axis by loosening the Dec. clutch and sliding the telescope's dovetail bar within the saddle until the optical tube stays put.

Achieving Alignment from 15° to 65° Latitude

The EQ8-Rh has a latitude adjustment range of 15° to 65°. Altitude is set with the latitude jackscrew and azimuth with two knobs over a ±10° range. The manual describes three polar alignment methods.

The SynScan hand controller shows the polar alignment error after a 2-star alignment, and its polar alignment routine guides the adjustments. For camera-based polar alignment, Sky-Watcher points to the free PHD2 and SharpCap software. An optional polar scope can also be installed for direct visual alignment with Polaris or Octans.

SynScan V5: Navigating a 42,000+ Object Database

The included SynScan V5 hand controller holds a database of over 42,000 objects, including the Messier, NGC, IC, and SAO catalogs, as well as double stars, variable stars, and planets. After a proper alignment procedure, the system's pointing accuracy is rated for up to 5 arc-minutes (RMS).

The SynScan system guides you through 1-Star, 2-Star, or 3-Star alignment routines. It can also display the position of Polaris in a polar scope reticle and reporting the calculated polar alignment error after a multi-star alignment.

ASCOM & App Control via USB and Optional Wi-Fi

The mount's control panel features a built-in USB port that provides a direct USB-to-serial connection for computer control. All of Sky-Watcher's control options support the ASCOM platform.

For mobile and wireless control, you can connect an optional SynScan Wi-Fi dongle to the hand controller port. This enables you to control the mount using the free SynScan Pro app, for iOS, Android or Windows. On Windows and Android the app also works over the built-in USB port.

200-Segment PPEC, Autoguiding, and Camera Control

It supports a 200-segment Permanent Periodic Error Correction (PPEC) function. Thanks to an index on the R.A. worm, the controller can permanently store a PEC training curve. After running a training routine once (either manually or with an autoguider), you can enable PEC at the start of any subsequent session to improve tracking, which is beneficial for short-focal-length astrophotography.

• Auto-Guiding: A standard ST-4 autoguide port works with any autoguider with an ST-4 type interface, with selectable guide speeds from 0.125x to 1x sidereal rate.
• Auto-Home: Two home position sensors enable the Auto-Home function, allowing the mount to return to a precise, repeatable home position after power-on when commanded by the SynScan controller.
• Camera Control: A built-in SNAP port and an included shutter release cable for Canon EOS cameras enable automated batch exposures. You can program up to 8 groups of exposure times and frame counts directly into the SynScan hand controller.

The 29.4 kg Pier Tripod and D-Style Saddle

The steel pier tripod weighs 29.4 kg (64.8 lb). The pier's height is adjustable from 800 mm to 1100 mm.

The tripod can be placed directly on level ground or on its three included adjustable stands, which feature large leveling screws. At the top, the EQ8-Rh is fitted with a D-style saddle with three knobs that are tightened alternately.

Powering the EQ8-Rh: DC 11-16V at 55W Minimum

The EQ8-Rh requires a DC power source supplying 11V to 16V with a minimum output of 55W. A higher voltage within this range is preferred for optimal motor performance. The control panel's LED provides a quick status check on the input voltage: it shines steadily for normal voltage, flashes slowly when voltage is low, and flashes rapidly when voltage is critically low, when continuing may damage the battery and the motor controller.

Do not use an unregulated AC-to-DC adapter. Sky-Watcher's 13.7V/4A AC-to-DC switching supply is highly recommended; a voltage outside 11V to 16V may permanently damage the motor controller or the hand controller.

First Night Setup: Assembling the EQ8-Rh and Pier Tripod

First, fully expand the pier tripod legs on level ground. For safety, the manual recommends placing one or both counterweights on the ground under the central post so that no one can put a foot under the post. After loosening the central post clamp, you can adjust the pier to the desired height and secure it.

Next, with the azimuth adjustment knobs loosened, you lift the 25.8 kg mount head and align it with the dowel on the tripod top, securing it with the azimuth locking screws and the primary locking knob. The counterweight rod is then screwed into the mount, followed by the counterweights. Finally, with the R.A. axis locked and the counterweight rod pointing down, you can safely install your telescope onto the D-style saddle and proceed with balancing the entire assembly.

Weights and Dimensions for Transport and Setup

Without a telescope, the parts below add up to 77.8 kg (171.5 lb).

• Mount Head Weight: 25.8 kg (56.9 lb)
• Pier Tripod Weight: 29.4 kg (64.8 lb)
• Counterweights: 2 x 10 kg (22 lb) each
• Counterweight Rod: 2.6 kg (5.7 lb)