In addition to being fully computerized with a database of over 40,000 celestial objects, the Celestron CGE Pro German Equatorial Mount 91529 has been completely redesigned to offer numerous design advantages for the Astrophotographer: Increased Payload Capacity that is able to hold our 14" SCT telescope more securely as well as larger optical tubes up to a maximum instrument capacity of 90 lbs (not including counterweights). All-Star Polar Alignment on this Telescope Mount from Celestron allows you to choose any bright alignment star for a software assisted alignment of the mount's polar axis that will have you ready for imaging even if you can't see the North Star. The Celestron CGE German Equatorial Mounting System has larger hand knobs for both Altitude and Azimuth adjustments. The Celestron CGE Mount features extended tracking past the Meridian of up to 20 degrees of uninterrupted imaging through the best part of the sky. Improved gearing and motors provide faster slew speeds than ever before with a maximum slew rate of over 5°/per second. Redesigned electronics on this Celestron Telescope Mount delivers constant regulated power to the motors making them capable of driving the telescope even when not perfectly balanced. This allows the Celestron CGE Pro Mount 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. The hallmark of any telescope mount is its ability to find, center and track celestial objects with the highest degree of accuracy. With just a standard hand control alignment, the CGE Pro has the ability to center a star in your eyepiece or CCD chip to within 5 arc minutes. Using NexStar's advanced pointing features such as Calibration Stars, Sync and Precise GoTo, further improves the pointing accuracy to as low as 1 arc minute in the desired region of the sky. With larger .75" pitch diameter worm gear and 6" pitch diameter worm wheel, precision made cut-steel gears in gearboxes, and seven slot-skewed armature motors, the CGE Pro delivers smooth +/- 5 arc second tracking accuracy typical unguided periodic error, which can be further reduced with PPEC. Celestron's NexStar hand control has built-in compensation features essential for accurately placing small objects on the center of your CCD chip or high power eyepiece. Aligning on multiple Calibration Stars creates a model of the opto-mechanical inaccuracies inherent in all equatorial mounts. This model is stored within the hand control and is used to compensate for these inaccuracies, thus improving your pointing precision each time you slew your telescope.) Celestron's NexStar hand control has built-in mount modeling features essential for accurately placing small objects on the center of your CCD chip or high power eyepiece. Aligning on multiple Calibration Stars creates a mathematical model of the opto-mechanical inaccuracies inherent in all equatorial mounts. This model is stored within the hand control and is used to compensate for these inaccuracies, thus improving your pointing precision each time you slew your telescope. And of course, the CGE Pro is also fully T-Point compatible (available from Software Bisque) for ultra precise pointing across the entire sky. In addition to these improvements, the Celestron line of German Equatorial mounts has long been recognized for features preferred by visual observers and astrophotographer alike. Among them include: Portability - Set up and transportation of the CGE Pro telescopes is made easy by separating the mount into smaller, easy-to-carry components. Unlike fork arm mounted telescopes, the CGE's optical tubes can be quickly removed from their mounts making even the CGE Pro1400 easily assembled in minutes. Stability - Recognized for superior stability, German Equatorial mounts place the center of gravity directly over the tripod or pier and can be easily polar aligned without the use of an optional equatorial wedge. This proven design reduces the "tuning fork" vibration that can be associated with undersized fork mounts. Balance - CGE Pro Equatorial mounts can easily be balanced in both axes. Simply sliding the counterweight for Right Ascension and moving the optical tube along its dovetail mounting for Declination, accomplish balancing the weight of camera equipment and other visual accessories. This means that no additional weight needs to be added to balance the telescope when additional accessories are added. Clearance - CGE Pro mounts support their tubes at a single contact point allowing the tube to move freely around its polar axis without making contact with the telescope's mount. Software features allow the user to set the mounts slew limits to guaranty safe motion. This is particularly useful when adding photographic and CCD instruments that extend from the rear of the telescopes. All CGE mounted telescopes are compatible with Celestron's SkySync GPS accessory. Combine the GPS and built-in real time clock, and these telescopes will keep track and remember their exact location and time without having to enter the information into the hand control. CGE PRO Tracking Data The following graphs display R.A. worm gear tracking accuracy of the CGE Pro Equatorial mount in 4 conditions: Figure 1 – Raw unguided tracking that isolates the periodic error; Figure 2 – Tracking with Permanent Periodic Error Correction (PPEC) enabled; Figure 3 – Guided tracking with an autoguider; and Figure 4 – Guided tracking with an autoguider and PPEC enabled. Data was acquired from Celestron’s engineering team using an EdgeHD 800 optical tube and NexImage camera at f/10. This data represents the typical performance of a CGE Pro under average seeing conditions from urban skies in Torrance, CA. Figure 2 has a cubic fit applied to the graph, and Figures 1, 3 and 4 have linear drift removed (to better show repeatable error). All Figures show 22 minutes of tracking, which covers 4 full rotations of the CGE Pro R.A. worm gear. Figure 1. This graph displays the R.A. worm gear tracking accuracy for a typical CGE Pro equatorial mount. The graph shows 4 periods of the worm gear which yields about +/-7 arc seconds of periodic error. The minimal periodic error is both very predictable and gradual, allowing short unguided images to be taken, or much longer exposures with extremely accurate tracking when used with an autoguider. Figure 2. With the CGE Pro’s Permanent Periodic Error Correction (PPEC) enabled, most of the periodic error is eliminated, leaving behind lesser tracking errors caused by atmospheric turbulence, wind, and opto-mechanical flexure. PPEC brings the CGE Pro’s R.A. tracking accuracy to about +/-2 arc seconds, allowing even longer unguided exposures (for uses like Hyperstar imaging). Figure 3. Autoguiding with the CGE Pro provides consistent tracking accuracy to within +/-2 arc seconds under average seeing conditions. Autoguiding provides an easy way to sustain long-exposure astro-images without excessive tracking error or drift. Figure 4. With autoguiding and PPEC enabled, we can take full advantage of the CGE Pro’s stability and tracking accuracy. Even under average seeing conditions, PPEC + autoguiding easily yields tracking accuracy of less than +/-2 arc seconds. Note that tracking errors of the mount have dropped so far below the noise floor set by the seeing conditions that they cannot be quantitatively distinguished from zero. The Celestron Pro CGE telescope Mount provides the best tracking accuracy, resulting in sharp, round stars in your astro-images.