EQ5 PRO mount

The Sky-Watcher EQ5 PRO German Equatorial Mount's Mechanical System . . .

  • Body: The rugged equatorial body of the EQ5 PRO mount is die-cast and machined from virgin aluminum and powder coated in classic scientific instrument white for long life. Large polar and declination castings provide stable thrust bearing surfaces with tight tolerances. Sealed ball-bearings are used on load-bearing surfaces in both right ascension and declination for smooth tracking with payloads up to 25 pounds. To make a casual polar alignment for visual use quick and easy, there's a latitude scale and fine adjustment controls in both altitude and azimuth. All drive gears, motors, and electronics are built into the equatorial body or into a separate motor-controller box.

  • Manual slow motion controls: Manual slow motion controls with thumb-locks are provided in RA and Dec to allow swift manual orientation of the optical tube assembly. Once roughly centered on an object, precision motorized RA and Dec centering and astrophotographic guiding movements are then controlled by push-buttons on the computer hand control.

  • Setting circles: Manual analog setting-circles are provided in both right ascension and declination axes for locating sky objects by their celestial coordinates as a backup for the digital RA and Dec readouts on the computer hand control.

  • Dovetail saddle: A Vixen-style dovetail slot is built into the top of the mount head. This accepts any optical tube using a Vixen-style dovetail slide bar and mounting rings. It allows the optical tube and dovetail to be quickly and precisely moved fore and aft on the mount to balance the optical tube as accessories are added or removed. This eliminates the need for an extra counterweight to balance a camera or other accessories in declination. Setup and takedown times are exceptionally fast, as a single large hand-tighten knob holds the optical tube dovetail bar in place. A second lock knob prevents the tube from sliding off the mount should the hand-tighten knob loosen.

  • Counterweight(s) and counterweight shaft: The counterweight shaft is machined from solid stainless steel. The number and weight(s) of the counterweights provided with a complete Sky-Watcher telescope/EQ5 Pro mount package will vary, depending on the weight of the optical tube being used. When the mount is purchased by itself, one 11 pound (5 kg) counterweight is provided. It is made of cast iron, powder coated instrument white for long life. It will balance equipment payloads up to approximately 15 pounds in weight (6.8 kg). Adding an optional second counterweight will let you balance instrument payloads up to 25 pounds (11.36 kg). The counterweight(s) lock in place with a single hand-tighten knob each, making it easy to rebalance the mount in right ascension if you change optical tubes or add heavy accessories.

  • Tripod: The all-metal tripod uses 1.75" diameter tubular steel legs with excellent damping characteristics. The mount for scopes 10" in aperture and larger uses 2" diameter steel legs. The tripod head is rigid cast aluminum. A spreader-bar with a tension-lock locks the legs open to insure optimum rigidity. The large circular central area of the spreader-bar is drilled to form a convenient accessory tray that holds eyepieces to keep them up out of the dew-soaked grass.

  • Polar Alignment Scope: A polar alignment scope (with diopter adjustment to match the scope to your eyesight) is installed in the center of the RA axis. A transparent etched glass reticle in the polar scope displays the regions around the celestial poles. For the northern hemisphere, the reticle shows the stars that make up the constellations of Cassiopeia and Ursa Major (the Big Dipper), and the position of Polaris, the North Star. Simply use the micrometric elevation and azimuth controls built into the mount to line up the actual stars of Cassiopeia, the Big Dipper, and Polaris as seen through the polar scope with their positions as shown on the reticle. This automatically centers the polar axis of the mount on the North Celestial Pole to achieve precise polar alignment for critical astrophotography. The reticle also shows the constellation Octans, whose star Sigma Octantis visually defines the position of the south celestial pole. This allows you to use the polar alignment scope in both northern and southern hemispheres.

The Sky-Watcher EQ5 PRO's Motor Drive System . . .

  • Motors and drive system: The computerized go-to EQ5 PRO German equatorial mount has built-in DC-powered high torque stepper motors for slewing and tracking. They turn dual-axis bronze worms that drive 72mm (2.83") diameter 144-tooth right ascension and declination gears. Stepper resolution is a tiny 0.28764 arc-seconds per step, yielding a very smooth and visually step-free tracking motion, even at very high magnifications. Tight tolerances and precise machining of both drive trains assure minimal backlash. When equatorially aligned, the mount will both slew to celestial objects under computer control and then very precisely track them in right ascension once they have been located. Snap-on covers keep the motor drives free from dust and debris.

  • Motor control system: The mount's stepper motors are controlled by an advanced Allegro DMOS IC driver using a dual full-bridge micro-stepping PWM (pulse width modulation) system to power the motors. The controller provides guiding speeds for astrophotography of 0.25x, 0.5x, 0.75x, and 1x sidereal. Available slewing speeds include 1.25x, 1.5x, 1.75x, 2x, 8x, 16x, 32x, 64x, 400x, 500x, 600x, 800x sidereal, or 3.4° per second. Pre-set lunar, solar, and sidereal tracking rates are available at the touch of a switch.

  • Power requirements: A car battery cord is supplied to power the EQ5 PRO. The cord has a male cigarette lighter plug on one end, with a tip positive 2.1mm mini plug on the other. This lets you operate the mount from the cigarette lighter of your car, from an optional rechargeable 12V battery pack, or from an optional user-supplied 12VDC power supply capable of providing 2000mA. The mount draws this high level of power only when accelerating briefly to slew heavy loads from a standing start. Power consumption during normal tracking is less than 750mA. The 7 amp hour capacity Celestron Power Tank #4512V and 17 amp hour capacity Celestron Power Tank #4517V rechargeable 12V batteries are recommended to power the EQ5 PRO in the field. The 17 amp hour model will operate the mount all night long without danger of running out of power.
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