Knowledge Base

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.

The NexStar computer hand control supplied with the Celestron CGEM telescopes is powered by the CGEM mount itself. No extra batteries or power supplies are needed. The

The NexStar computer has a built-in database of more than 40,000 stars and objects it can find and track for you. These include the complete RNGC, Messier, Caldwell, IC, and Abell catalogs; selected SAO stars; the planets, the Moon, and others. The custom database lists of all the most famous deep-sky objects by name and catalog number; the most beautiful double, triple and quadruple stars; selected variable stars; non-planetary solar system objects; and asterisms. You can also store and edit the right ascension and declination of 400 additional user-defined objects of your own choosing, such as the comet and asteroid coordinates published monthly in Astronomy and Sky & Telescope magazines. The computer control can find any of those objects with only a few keystrokes, and track them with high accuracy for visual or photographic applications. There is enhanced information on over 200 of the most note-worthy objects.

All of the database and mount operation information is displayed on a double line, 16-character, liquid crystal display on the NexStar hand control. There are 19 fiber optic backlit LED buttons to make it easy for you to control the NexStar computer without affecting your dark-adapted vision. An RS-232 communication port on the hand control allows you to operate your telescope remotely via a personal computer using the supplied RS-232 cable and NexRemote software CD-ROM.

The NexStar hand control provides a constant digital r. a. and dec readout of your scope's position on the sky. This provides much greater accuracy than conventional manual setting circles for star-hopping or locating objects by their celestial coordinates alone, should you want to observe the old-fashioned way without using the computer to find objects for you.

The software built into the CGEM NexStar hand control includes mount calibration, database filter limits, hibernate, five alignment procedures, user-defined slew limits, a new "All-Star" polar alignment routine that uses any bright star for a quick and accurate polar alignment, and more. Built-in adjustable backlash compensation permits precise corrections during astrophotography and when observing visually at high powers. A high precision pointing subroutine in the computer lets you point accurately at objects that you want to photograph that are too dim to be seen though the scope.

The software includes permanent programmable periodic error correction (PEC) to correct for the minor periodic tracking errors inherent to all worm drives that might otherwise mar your long exposure photographs. The NexStar computer retains the PEC corrections when it is powered down. The hand control and motor control software is flash-upgradeable to allow you to download the latest product updates over the Internet to keep your NexStar computer control always at the cutting edge of technology.

Five different alignment methods are built into the NexStar computer - 2-star align, quick align, 1-star align, last alignment, and solar system align - allowing you to choose a level of computer accuracy in automatically finding objects with which you are comfortable. Alignment is easily accomplished in only a few short minutes. You can be observing in less than 15 minutes after you first take your CGEM-mounted scope outdoors.

In addition, the NexStar computer hand control is GPS-compatible (using an optional inexpensive CN16 GPS module) for full GPS (Global Positioning System) satellite accuracy. Adding GPS to the computer is something no competitively-priced mount can do. Once the scope is approximately polar aligned, the 16-channel CN16 GPS system uses signals from government satellites to calculate the scope's location on earth with an accuracy measured in meters. The system also calculates the current time based on the split second accuracy of the GPS time signals. After the CN16 quickly completes these calculations and enters the information into the computer control for you automatically, the computer can then orient the scope with the sky, slew to a pair of guide stars, ask you to confirm that the stars are in the center of the field (and center them if they're not precisely aligned), and then start finding and tracking over 40,000 objects for you at your command. With the CGEM go-to mount and the CN16, orienting your scope in time and space on earth and aligning it on the sky becomes almost as easy a task as simply turning the mount on.

The German equatorial mount has long been the favored choice of astronomy buffs
and astrophotographers because of its stability and portability. It is more stable
because the center of gravity is directly over the center of its base, and more
portable because it can be broken down into smaller component parts than a fork-mount
telescope for easy storage and transportation.

For astrophotography, the German equatorial mount offers easier balancing; unlimited
space at the rear of the telescope tube to mount a long camera equipment train that
can't bump into the drive base, as is the case with many fork-mounted scopes; and
whole sky access that many fork-mounted scopes can't achieve.

The Celestron CGEM - a Sky & Telescope
Hot Product for 2010 - is a newly-designed heavy-duty computerized
go-to German equatorial mount. The ergonomically designed CGEM has a fresh, attractive,
bold appearance. It has a 40 pound payload capacity. This allows it to carry Celestron
SCT optical tubes up to 11" in aperture, plus a full load of imaging accessories,
as well as virtually any other optical tube and accessory payload less than 40 pounds
in weight. The Sky & Telescope Hot Product citation said the CGEM mount offers
"unquestionable value when it comes to Go To performance for astrophotographers
and observers."

The CGEM mount head contains dual-axis slewing/tracking motors on each axis for
go-to computer control. Steel worm gears and 90mm diameter brass worm wheels assure
long-term reliability and high accuracy performance. The use of low cog DC Servo
motors with integrated optical positioning encoders offers smooth, quiet operation
and precision slewing and tracking. The motor armatures are skewed to minimize cogging
for precise jitter-free low speed tracking. The motor drives and their wiring are
all internal, keeping them snag-free and free from dust and debris.

The mount requires 1.5 amp 12 VDC power to operate. The maximum 1.5 amp power draw
happens only briefly when accelerating to the high speed slewing mode from a standing
start. Normal power draw with a well-balanced payload is generally less than half
the maximum draw. The mount comes with a car battery cord to operate from the cigarette
lighter plug of your car or from a rechargeable 12V battery pack. The 17 amp hour
capacity Celestron Power Tank #4517V is recommended and will operate the mount all
night long without danger of running out of power.

To make a casual polar alignment for visual use quick and easy, there's a latitude
scale with large ergonomically-friendly altitude and azimuth adjustment knobs. If
serious long exposure astrophotography is in your plans, an optional polar finder
is available to increase the accuracy of your alignment.

The supplied 17 pound counterweight (one comes with the 8" CGEM800; two come with
the 9.25" CGEM925 and 11" CGEM1100) is locked in place on the steel counterweight
shaft with a single hand-tighten knob, making it easy to rebalance your scope in
right ascension if you add heavy photographic accessories. If needed, optional counterweights
are available to balance very heavy loads.

For observing or imaging objects near the meridian (the imaginary line passing directly
overhead from North to South), the CGEM is designed to track well past the meridian
for uninterrupted imaging through the most ideal part of the sky.

There are nine motor drive speeds: 0.5x and 1x sidereal for guiding; 4x, 8x, 16x,
and 64x for centering; and 1°, 2°, and a fast 5° per second for slewing. Preset
tracking rates include sidereal, solar, and lunar. Equatorial tracking modes are
available for both northern and southern hemispheres.

An autoguider port is located on the electronic pier for long exposure astrophotography.
The autoguider port can use a six-pin RJ-12 modular jack ST-4 compatible CCD autoguider
to automatically control the drive motors during long exposure astrophotography.

The CGEM mount's adjustable height tripod has 2" diameter stainless steel legs with
a metal center leg brace for rigidity to provide excellent damping characteristics.
The center leg brace is drilled to form a convenient accessory tray that holds 1.25"
and 2" eyepiece to keep them up out of the dew-soaked grass.

Optical tubes are installed on the CGEM mount using a slot on the mount head that
accepts a Celestron CGE-style or Losmandy D-plate dovetail slide bar. This allows
the optical tube to be quickly and precisely balanced fore and aft on the mount
in declination, eliminating the need for an extra counterweight to balance a camera
or other accessories. Setup and takedown times are exceptionally fast, as a single
large hand-tighten knob holds the optical tube in place. A second lock knob prevents
the tube from sliding off the mount should the hand-tighten knob loosen.

The CGEM mount weighs 75 pounds. The equatorial head is the heaviest component,
at 41 pounds. The tripod weighs 17 pounds, as does the supplied counterweight(s)
- one comes with the 8" CGEM800; two come with both the 9.25" CGEM925 and the 11"
CGEM1100.

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

• Body: The rugged equatorial body of the manual version of the EQ5 PRO 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. Right ascension and declination slow motion control gears are built into the equatorial body.
  

• Manual slow motion controls: Precisely-geared manual slow motion controls are provided in RA and Dec. Thumb-locks disengage the slow motion controls to allow swift manual orientation of the optical tube assembly. Once roughly centered on an object, the thumb-locks are re-engaged and precision centering and tracking is then controlled by deluxe spring-steel cable control knobs.
  

• Setting circles: Manual analog setting-circles are provided in both right ascension and declination axes for locating sky objects by their celestial coordinates.
  

• 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 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 manual mount package will vary, depending on the weight of the optical tube being used. When the mount is purchased by itself, the two 11 pound (5 kg) counterweights are provided. They are made of cast iron, powder coated white for long life. Use one or both, depending on the weight of the optical tube you are balancing. Using both will let you balance payloads up to 25 pounds (11.36 kg), with no additional counterweights needed. The counterweights 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.
  

• Optional go-to motor drive system: The EQ5 PRO manual mount is upgradeable at a later date to a fully-computerized go-to drive by adding an optional Sky-Watcher SynScan motor control system.

The Sky-Watcher EQ5 PRO's SynScan Computer Control System . . .

• Computer hand control: The computerized Sky-Watcher go-to EQ5 PRO mount uses the revolutionary SynScan computer controller. In addition to fully computerized go-to operation, SynScan also allows you to use the mount manually, using the computer to control the movement of the mount as you search the skies on your own, star-hopping from object to object. The SynScan's hand control plugs into the EQ5 PRO's motor-control panel. Unlike other controllers, the easy-to-read, 2-line, 16-character backlit LCD display of the SynScan controller will display clearly in temperatures as cold as approximately 10 degrees below zero Fahrenheit. There are 19 fiber optic red-backlit positive-contact pushbuttons (not failure-prone membrane-type buttons) to make it easy for you to control the computer without affecting your dark-adapted vision. An RS-232 communication port on the hand control allows you to operate the telescope remotely via a personal computer using any ASCOM-compliant software program. A serial PC connector/hand-controller phone-jack plug computer interface cable is included.
  

• Built-in programs: Several different alignment methods are built into the SynScan computer, allowing you to choose the level of computer accuracy in automatically finding objects with which you are comfortable. One, two, and (more accurate) three star computer-guided alignment methods are easily accomplished in only a few short minutes. You can be observing in less than 15 minutes after you first take the scope outdoors, including telescope assembly time. The EQ5 PRO mount is compatible with operations in both the Northern and Southern hemispheres. There is a GPS upgrade option to facilitate entering ultra-precise time, date, and location. There is an auto-guider port for hands-free guiding of the mount during astrophotography. Backlash compensation is provided in both RA and Dec to keep the slewing and tracking response prompt and uniform.
  

• Periodic error correction: The SynScan firm-wear includes a programming algorithm for periodic error correction. The PEC circuit eliminates the unavoidable small tracking errors in right ascension that are common to all worm-gear drive systems, no matter what size the telescope or what its cost. Such errors are only of concern during long exposure deep space astrophotography. Visual observing is not affected by periodic drive errors.
  

• Computer database: The SynScan computer includes a celestial database of over 30,000 objects, including all the crowd pleasers like the planets, the Moon, Messier objects, and interesting double stars. In addition, the library includes many objects for advanced study in the CNGC, IC, and Caldwell catalogs, plus other specialized lists. There is also the provision for adding 25 user-defined celestial favorites.

Features of this Telescope's Optical System . . .

• Advanced Coma-Free catadioptric designed to emulate the optical performance of a Ritchey-Chrétien telescope: The traditional two-mirror Ritchey-Chrétien (R-C) design uses two large hyperbolic primary and secondary mirrors to produce images that are free from coma over a wide field. Because of this wide coma-free field and a relatively fast focal ratio, the Ritchey-Chrétien design is particularly well suited to astrophotography. The R-C is the design of choice for most of the major professional observatory telescopes built in the last half-century. For example, the Hubble Space Telescope and the twin 10-meter Keck telescopes in Hawaii are Ritchey-Chrétiens.
  
      However, because of the complexity of fabricating and testing a large aperture hyperbolic mirror (just ask the people who built the initially-flawed, but not discovered until it was in space, Hubble Space Telescope), traditional large aperture two-mirror Ritchey-Chrétiens are very expensive to manufacture and purchase, too expensive for many amateur astronomers.
  
      To emulate the coma-free performance of a true R-C telescope, while keeping the cost very much within reason, each Meade Advanced Coma-Free (ACF) catadioptric optical system uses a full aperture aspheric corrector lens in conjunction with a simple spherical primary mirror. This creates a two-element primary mirror system that performs like an R-C's single hyperbolic primary mirror from the optical point of view of the system's secondary mirror. The hyperbolic secondary mirror itself is mounted directly on the rear of the corrector lens, rather than in the traditional R-C's conventional spider vane assembly. This eliminates the image-degrading diffraction spikes of the secondary mirror support structure visible in commercial R-C scope images. The result is R-C-class coma-free wide-field performance, at only a fraction the cost of most true R-C systems.
  
      The corrector-modified design would itself be expensive to fabricate were it not for Meade's more than a quarter-century of experience making Schmidt-Cassegrain correctors, which are in the same optical family as the corrector needed for the coma-free design of the ACF scopes. An additional benefit of the full aperture corrector in the ACF design is slightly better correction for astigmatism than the traditional R-C design.
  
      In addition, the ACF design, due to its front corrector plate, is a closed tube design. This keeps the primary optical components protected from dust, moisture and other contaminants that might fall on the optical surfaces of the primary and secondary mirrors as can happen with the traditional open-tube R-C design.
  
      While the ACF scopes may not be traditional R-C designs, their performance is R-C-like in all important characteristics. A review in Sky & Telescope magazine of the ground-breaking predecessor of the Meade ACF optics said the bottom line is that the optics do "indeed perform like a Ritchey-Chrétien." Another such review, in Astronomy magazine said, "This scope delivers Ritchey-Chrétien-like performance at a fraction of the cost."
  
  • Low thermal expansion mirrors: The primary and secondary mirrors are made of low thermal expansion Pyrex to limit any possible focal length change as the temperature drops. This reduces the possibility of the focus changing during critical through-the-scope CCD imaging.
    

  • Oversized primary mirrors: The diameter of the primary mirror of each ACF scope is larger than the diameter of the corrector lens at the front of its optical tube that admits the light. For example, the primary mirror of the 8" scope is actually 8.25" in diameter, compared to the 8" diameter of the corrector lens. Oversizing the primary mirror in this way gives you a wider fully-illuminated field than a conventional catadioptric scope whose corrector and primary mirror are the same size. The result is a gain of 5% to 8% more off-axis light available to your eye or camera, depending on the telescope model.
    

  • Fully multicoated UHTC (Ultra High Transmission Coatings) optics: The primary and secondary mirrors are vacuum-coated with aluminum, enhanced with multiple layers of titanium dioxide and silicon dioxide for increased reflectivity. A final layer of durable silicon monoxide (quartz) assures long life.
    
        A series of anti-reflective coatings of aluminum oxide, titanium dioxide, and magnesium fluoride are vacuum-deposited on both sides of the full aperture corrector plate. These antireflection multicoatings provide a high 99.8% light transmission per surface, versus a per-surface transmission of 98.7% for standard single-layer coatings. Overall light throughput (the amount of light collected by the objective lens that actually reaches your eye or camera) is approximately 89% at the focal plane.
    
        UHTC multicoatings provide a 15% increase in light throughput compared with standard single-layer coatings. . For example, they effectively add the equivalent of a little more than four-tenths of an inch of extra light-gathering aperture to the performance of the 6" optical system - but with no increase in actual size or weight. The UHTC multicoatings also improve contrast, for lunar and planetary images that appear sharper and more crisply defined.
    

  • Fully baffled optics: A cylindrical baffle around the secondary mirror, in combination with the cylindrical baffle tube projecting from the center of the primary mirror, prevents stray off-axis light from reaching the image plane. In addition, a series of field stops machined into the inner surface of the central baffle tube effectively eliminates undesirable light which might reflect from the inside surface of the tube. The result of these baffle systems is improved contrast in lunar, planetary, and deep space observing alike.

The German equatorial mount has long been the favored choice of astronomy buffs
and astrophotographers because of its stability and portability. It is more stable
because the center of gravity is directly over the center of its base, and more
portable because it can be broken down into smaller component parts than a fork-mount
telescope for easy storage and transportation.

For astrophotography, the German equatorial mount offers easier balancing; unlimited
space at the rear of the telescope tube to mount a long camera equipment train that
can't bump into the drive base, as is the case with many fork-mounted scopes; and
whole sky access that many fork-mounted scopes can't achieve.

The Celestron CGE PRO - a Sky & Telescope
Hot Product for 2010 - is a newly-designed high payload capacity/high
precision go-to German equatorial mount that epitomizes all of these German equatorial
mount virtues. The CGE PRO has a full 90 pound payload capacity. This allows it
to carry Celestron SCT optical tubes up to 14" in aperture, with as much as 45 pounds
of imaging accessories attached, as well as virtually any other optical tube and
accessory payload weighing up to 90 pounds. The mount is capable of operating over
a latitude range of 10º to 65º in both northern and southern hemispheres. The Sky
& Telescope Hot Product citation said the CGE PRO mount offers "unquestionable
value when it comes to Go To performance for astrophotographers and observers."

The mount's heavy duty right ascension and declination shafts are precision-machined
from 1.57" diameter steel tubing with a stout 0.40" wall thickness. Each shaft is
supported by two preloaded 2.68" O.D. tapered roller bearings. There is a four-point
right ascension and declination clutch system for no-slip pointing precision.

The CGE PRO mount head contains 12VDC slewing/tracking motors with integrated optical
encoders on each axis for go-to computer control. Steel worm gears and brass worm
wheels assure long-term reliability and high accuracy performance. Each precision-made
steel worm gear is 0.75" diameter and is preloaded with two 0.87" OD ball bearings
to minimize run-out (a source of periodic error). The precision-made 255 tooth brass
worm wheel is a full 6" in diameter.

The use of low cog DC Servo motors with integrated optical positioning encoders
offers smooth, quiet operation and precision slewing and tracking. The seven slot
motor armatures are skewed to minimize cogging for precise jitter-free low speed
tracking. The declination worm is spring loaded to minimize backlash for smoother
and easier guiding.

Drive accuracy (periodic error) is a very good +/- 9 arc seconds or better. This
can be further improved by training the permanent periodic error correction circuit
built into the mount's computer hand control to reduce the periodic error inherent
in all telescope worm gear drives.

There are nine motor drive speeds: 0.5x and 1x sidereal for guiding; 4x, 8x, 16x,
and 64x for centering; and 0.5°, 2°, and a fast 5.5° per second for slewing. Preset
tracking rates include sidereal, solar, and lunar. Equatorial tracking modes are
available for both northern and southern hemispheres.

The mount requires 2.5 amp 12 VDC power to operate. The maximum 2.5 amp power draw
happens only briefly when accelerating to the high speed slewing mode from a standing
start. Normal power draw with a well-balanced payload is generally considerably
less than half the maximum draw. The mount comes with a car battery cord to operate
from the cigarette lighter plug of your car or from a rechargeable 12VDC battery
pack. The 17 amp hour capacity Celestron Power Tank #4517V is recommended and will
operate the mount all night long without danger of running out of power.

Specially designed power management electronics deliver constant regulated power
to the motor so that it is capable of driving the mount even when your scope not
perfectly balanced. This allows the CGE Pro to have the payload capacity of that
of much larger (and expensive) mounts without sacrificing smooth tracking motion
and pointing accuracy across the entire sky.

To make a casual no-tool polar alignment for visual use quick and easy, there's
a latitude scale with large ergonomically-friendly altitude and azimuth adjustment
knobs. If serious long exposure astrophotography is in your plans, special All-Star
Polar Alignment software allows you to choose any bright alignment star for a software-assisted
alignment of the mount's polar axis, even if you can't see the North Star.

The CGE Pro mount alone comes with one 22 pound counterweight. When the mount is
supplied as part of a complete telescope package, one counterweight comes with the
9¼" CGE 925 PRO; two come with the 11" CGE 1100 PRO, and three come with the 14"
CGE 1400 PRO and CGE 1400 PRO Fastar. The counterweight is locked in place on the
5 pound steel counterweight shaft with a single hand-tighten knob, making it easy
to rebalance your scope in right ascension if you add heavy photographic accessories.
If needed, optional counterweights are available to balance very heavy loads.

For observing or imaging objects near the meridian (the imaginary line passing directly
overhead from North to South), the CGE PRO is designed to track a full 20° past
the meridian for uninterrupted imaging through the most ideal part of the sky.

An autoguider port, PC port, and auxiliary ports are located on the mount's electronic
pier for long exposure astrophotography. The autoguider port can use a six-pin RJ-12
modular jack ST-4 compatible CCD autoguider to automatically control the drive motors
during long exposure astrophotography. An RS-232 communication port on hand control
allows you to control the mount via a personal computer using the supplied NexRemote
telescope control software.

The CGE PRO mount's adjustable height Super HD tripod has 2.75" diameter stainless
steel legs. It adjusts over a 38" to 55" height range. The height adjustment leg
locks are on the inside of the tripod legs to keep them from snagging on clothing
in the dark. The tripod uses a dual leg support for maximum rigidity, with an upper
leg brace to provide an outward preload and a lower leg brace providing inward tension.
The upper leg brace forms a convenient tray that holds eyepieces and accessories
to keep them up out of the dew-soaked grass.

Optical tubes are installed on the CGE PRO mount using a slot on the mount head
that accepts a Celestron CGE-style or Losmandy D-plate dovetail slide bar. This
allows the optical tube to be quickly and precisely balanced fore and aft on the
mount in declination, eliminating the need for an extra counterweight to balance
a camera or other accessories. Setup and takedown times are exceptionally fast,
as a single large hand-tighten knob holds the optical tube in place. A second lock
knob prevents the tube from sliding off the mount should the hand-tighten knob loosen.

The CGE PRO mount weighs a stout 154 pounds. The equatorial head is the heaviest
component, at 75 pounds. The tripod and electronic pier weigh a combined 52 pounds.
The supplied counterweight weighs 22 pounds, while the thread-in counterweight shaft
weighs 5 pounds. With a deadweight lift of 75 pounds to install the equatorial head
on the tripod, it might be prudent to have a second person assist you in assembling
your CGE Pro mount.