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Celestron CGEM II 800 EdgeHD Telescope
Celestron CGEM II 800 EdgeHD Telescope
Celestron CGEM II 800 EdgeHD Telescope
Celestron CGEM II 800 EdgeHD Telescope

Celestron CGEM II 800 EdgeHD Telescope

by Celestron
SKU CEL-12017
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$3,599.00
$3,599.00 - $3,599.00
$3,599.00
$3,099.00
$3,099.00 - $3,099.00
$3,099.00
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  • 8-inch (203mm) EdgeHD Optical Tube
  • CGEM II German Equatorial Mount
  • StarBright XLT Optical Coatings
  • 40,000+ Object NexStar+ Database
  • 40 lb (18 kg) Payload Capacity
  • All-Star Polar Alignment
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  • Description
  • FAQ
  • Specifications
  • In the Box
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  • Warranty

  • The Celestron CGEM II 800 EdgeHD Telescope: Precision Visuals and Imaging Foundation

    The Celestron CGEM II 800 EdgeHD Telescope combines an advanced 8-inch aplanatic optical system with a robust, computerized German equatorial mount, creating a versatile platform for both demanding visual observers and serious astrophotographers. This instrument is engineered to deliver sharp, coma-free images across the entire field of view, making it an ideal choice for capturing wide-field deep-sky objects or resolving fine planetary details.

    EdgeHD Optics: Flat Fields and Pinpoint Stars

    At the heart of this system is the 8-inch EdgeHD optical tube, a sophisticated aplanatic Schmidt-Cassegrain design. Unlike traditional Schmidt-Cassegrains, the EdgeHD incorporates a dual-lens field corrector within the baffle tube, which works to eliminate both field curvature and off-axis coma. The practical result is that stars appear as pinpoint dots from the center of your view all the way to the very edge, even when using wide-field eyepieces or large camera sensors.

    This flat-field performance is crucial for astrophotography, as it ensures uniform star quality across the entire frame, minimizing the need for extensive post-processing corrections. Visually, it provides a more immersive experience, where the entire expanse of an open cluster or the arms of a spiral galaxy remain sharp and detailed, rather than blurring towards the periphery.

    StarBright XLT Coatings: Maximizing Light Throughput

    The EdgeHD optical system is further enhanced by Celestron's proprietary StarBright XLT optical coatings. These multi-layer coatings are applied to every optical surface, including the primary mirror, secondary mirror, and corrector plate, to maximize light transmission across the visual spectrum. This meticulous coating process means more photons reach your eye or camera sensor, resulting in brighter images and improved contrast.

    The benefit is particularly noticeable on faint deep-sky objects, where subtle details and nebulosity become more apparent. For planetary observers, the enhanced contrast helps to bring out the delicate banding on Jupiter or the intricate crater details on the Moon, even under challenging seeing conditions.

    Precise Mirror Focusing with Integrated Clutches

    The internal mirror focusing system of the EdgeHD 800 allows for smooth, precise adjustments to achieve critical focus. To address the common issue of mirror shift (or "image shift") during long-exposure imaging, this optical tube features integrated mirror clutches. Once focus is achieved, these clutches securely lock the primary mirror in place, preventing any unwanted movement that could degrade image quality.

    This locking mechanism provides peace of mind for astrophotographers, ensuring that focus remains stable throughout extended imaging sessions. For visual observers, it means less time re-focusing and more time enjoying stable, sharp views, particularly at high magnifications.

    Optical Tube Ventilation for Rapid Cool Down

    Achieving thermal equilibrium between your telescope's optics and the ambient air is essential for sharp viewing. The EdgeHD 800 incorporates integrated tube vents located on the rear cell of the optical tube. These vents, equipped with 95-micron mesh filters to prevent dust intrusion, allow warm air to exit the optical tube, drawing in cooler ambient air.

    This active ventilation significantly reduces the time required for the telescope to cool down to ambient temperature, minimizing tube currents and boundary layer effects that can degrade image quality. For observers with limited observing time, this means getting to optimal performance faster and enjoying clearer, steadier views.

    The CGEM II Mount: Stable Tracking and GoTo Accuracy

    Supporting the 8-inch EdgeHD optical tube is the Celestron CGEM II German Equatorial Mount, designed to provide a stable and accurate tracking platform with a substantial 40 lb (18 kg) payload capacity. Its robust construction, including heavy-duty DC servo motors and steel worm gears, ensures smooth, precise motion across both axes, which is critical for long-exposure astrophotography and high-magnification visual observing.

    The CGEM II's tracking accuracy minimizes star trailing in images and keeps celestial objects centered in the eyepiece, even at the highest powers. Its impressive payload capacity means you can comfortably add accessories like guide scopes, cameras, and filter wheels without compromising stability or tracking performance.

    Intuitive NexStar+ Control and All-Star Polar Alignment

    Navigating the night sky is simplified with the included NexStar+ hand controller. With a database of over 40,000 celestial objects, the GoTo system accurately points the telescope to your chosen target with the press of a button. Beyond simple pointing, the CGEM II features Celestron's All-Star Polar Alignment procedure.

    This innovative software routine allows you to achieve precise polar alignment even if your view of the celestial pole is obstructed, using any bright star in the sky. For astrophotographers, this means less time spent on setup and more time capturing stunning images, knowing your mount is accurately aligned for optimal tracking.

    Permanent Periodic Error Correction for Astrophotography

    For those serious about deep-sky astrophotography, the CGEM II mount incorporates Permanent Periodic Error Correction (PPEC). This feature allows you to train out the subtle, repeatable mechanical inaccuracies inherent in any worm gear system. Once recorded, the mount continuously applies these corrections, significantly reducing periodic error.

    The result is smoother tracking and much rounder stars in long-exposure images, allowing for longer unguided sub-exposures under favorable conditions. This capability helps bridge the gap between entry-level and advanced astrophotography mounts, providing a solid foundation for capturing high-quality celestial images.

    The 800 EdgeHD Experience: Views from the CGEM II

    The 8-inch EdgeHD on a CGEM II mount opens up a universe of possibilities. On a crisp, dark night, point the system at the Andromeda Galaxy (M31). The wide true field of view, combined with the aplanatic optics, allows you to frame the entire galaxy, revealing its bright core and extended spiral arms against a backdrop of pinpoint stars, all sharp to the very edge of your eyepiece or sensor. The CGEM II's tracking keeps M31 steadily centered, allowing for extended visual study or long photographic exposures.

    When turned to Jupiter, the 8-inch aperture gathers enough light to resolve the Great Red Spot, intricate cloud bands, and the subtle dance of its Galilean moons. The stable CGEM II mount and precise focusing system allow you to push magnifications to the limits of atmospheric seeing, revealing fine details that would be lost on lesser instruments. While an 8-inch aperture can be affected by turbulent seeing, under steady conditions, this telescope delivers exceptional resolution and contrast for both planetary and deep-sky targets.

    Comparative Perspective: Choosing Your Celestron EdgeHD

    The Celestron CGEM II 800 EdgeHD sits as a powerful, mid-range option within Celestron's EdgeHD and GoTo mount families.

    When compared to larger EdgeHD models like the 9.25-inch or 11-inch, the 800 EdgeHD maintains a more manageable size and weight, making it easier to transport and set up for individual observers. The CGEM II mount is perfectly matched to the 800 EdgeHD's weight, offering excellent stability and tracking without the need for a heavier, more complex mount like the CGX or CGX-L, which are often required for the larger EdgeHD optical tubes. This balance of aperture, performance, and portability makes the 800 EdgeHD a compelling choice for a wide range of observers and imagers.

  • What makes EdgeHD optics different from a standard Schmidt-Cassegrain?

    EdgeHD optics incorporate a built-in field corrector that eliminates both field curvature and off-axis coma, ensuring stars appear sharp and pinpoint across the entire field of view, especially beneficial for astrophotography with large sensors.

    What is the payload capacity of the CGEM II mount?

    The Celestron CGEM II mount has a maximum payload capacity of 40 pounds (18 kg), allowing it to comfortably support the 800 EdgeHD optical tube and additional accessories like cameras, guide scopes, and filter wheels.

    Can I use this telescope for astrophotography?

    Yes, the CGEM II 800 EdgeHD is highly capable for astrophotography. Its aplanatic optics provide a flat, coma-free field, and the CGEM II mount offers precise tracking, Permanent Periodic Error Correction (PPEC), and All-Star Polar Alignment for long-exposure imaging.

    How does the mirror locking system benefit observing?

    The mirror locking system prevents mirror shift (image shift) once focus is achieved. This ensures that your image remains stable and sharp, which is critical for high-magnification visual observations and essential for maintaining focus during long astrophotography exposures.

    Is the CGEM II 800 EdgeHD difficult to set up for a beginner?

    While an 8-inch telescope on an equatorial mount requires a learning curve, Celestron's NexStar+ hand controller and All-Star Polar Alignment make the GoTo and setup process intuitive. Many resources are available to guide new users through initial setup and operation.

    What accessories are recommended for this telescope?

    Consider a focal reducer (like the Celestron .7x EdgeHD reducer) to achieve a faster focal ratio for wide-field imaging, a dew shield to prevent dew formation on the corrector plate, and a power tank for extended field operation.

  • Optical Design EdgeHD Aplanatic SCT
    Aperture 8 inches (203mm)
    Focal Length 2032mm
    Focal Ratio f/10
    Optical Coatings StarBright XLT
    Mount Type CGEM II Computerized German Equatorial
    Payload Capacity 40 lbs (18 kg)
    Tracking Speeds Sidereal, Solar, Lunar
    Slew Speeds 9 slew speeds, max 5°/sec
    GoTo Database 40,000+ objects
    Polar Alignment All-Star Polar Alignment
    Periodic Error Correction Permanent Periodic Error Correction (PPEC)
    Tripod 2" Stainless Steel Legs
    Optical Tube Weight 14 lbs (6.35 kg)
    Mount Head Weight 42 lbs (19 kg)
    Tripod Weight 20 lbs (9 kg)
    • Celestron 800 EdgeHD Optical Tube

      Celestron 800 EdgeHD Optical Tube

      × 1

    • Celestron CGEM II Mount Head

      CGEM II Mount Head

      × 1

    • Celestron Heavy Duty Steel Tripod

      Heavy-Duty Steel Tripod

      × 1

    • Celestron NexStar+ Hand Controller

      NexStar+ Hand Controller

      × 1

    • Celestron 9x50 Finderscope

      9x50 Finderscope

      × 1

    • Celestron 23mm Luminos Eyepiece

      23mm Luminos Eyepiece

      × 1

    • Celestron 2-inch Star Diagonal

      2-inch Star Diagonal

      × 1

    • Celestron 1.25-inch Visual Back

      1.25-inch Visual Back

      × 1

    • Celestron DC Power Cable

      DC Power Cable (Car Battery Adapter)

      × 1

  • Celestron 2-Year Limited Warranty