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Celestron C9.25 OTA - CGE Dovetail
Celestron C9.25 OTA - CGE Dovetail
Celestron C9.25 OTA - CGE Dovetail
Celestron C9.25 OTA - CGE Dovetail

Celestron C9.25 OTA - CGE Dovetail

by Celestron
SKU CEL-91027-XLT
$2,000.00 - $2,000.00
$2,000.00
$2,000.00 - $2,000.00
$2,000.00
Price Match Policy!
  • 235mm (9.25") Schmidt-Cassegrain Optical Tube
  • 2350mm Focal Length (f/10)
  • StarBright XLT Optical Coatings
  • Fastar-Compatible for f/2 Imaging
  • 20 lb Optical Tube Weight
  • CGE-Style Dovetail Bar
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Celestron C9.25 Optical Tube Assembly (CGE Dovetail)

    The Celestron C9.25 Optical Tube Assembly delivers the perfect balance of aperture and portability with its 235mm (9.25") primary mirror and 2350mm focal length. This f/10 system achieves a Dawes resolution of 0.49 arc seconds and gathers 1127x more light than the human eye, revealing intricate detail on planets and faint deep-sky objects. Weighing just 20 lbs and measuring 22" in length, the C9.25 provides a significant astronomical advantage in a manageable package.

    The 9.25" Aperture Advantage: 0.49 Arc Second Resolution

    The C9.25's unique 235mm aperture is a significant step up from 8-inch designs, translating directly to higher resolution and brighter images. With a theoretical Dawes limit of 0.49 arc seconds, you can resolve tighter double stars and finer detail in planetary cloud bands. This optical power allows you to push magnification up to 555x on steady nights and reach a limiting stellar magnitude of 14.4, pulling in faint galaxies and globular cluster cores that smaller apertures struggle with.

    StarBright XLT Coatings for 1127x Light Gathering

    Every glass surface in the C9.25 is treated with Celestron's premium StarBright XLT coatings, a sophisticated system of multi-layer mirror and anti-reflective coatings that maximize light transmission. These coatings ensure that the maximum number of photons from your target reach the eyepiece, boosting the OTA's 1127x light-gathering power. The result is visibly higher contrast that makes planetary features pop and reveals faint, extended nebulosity against a dark sky background.

    Fastar-Ready: Transform to an f/2 Imaging Platform

    For the astrophotographer, the C9.25 offers a critical advantage: it is Fastar-compatible. By replacing the secondary mirror with a third-party lens assembly, you can place a camera at the front of the telescope, transforming it into an incredibly fast f/2 imaging system. This configuration reduces exposure times by a factor of 25 compared to imaging at the native f/10, allowing you to capture high-quality images of large nebulae and galaxies in just seconds.

    A Portable 20 lb OTA with CGE Dovetail Mounting

    Despite its impressive aperture, the Celestron C9.25 remains highly portable. The aluminum optical tube weighs only 20 lbs and is just 22" long, making it easy for a single person to lift and mount. It comes equipped with a CGE-style dovetail bar, the larger and more rigid standard, ensuring a secure connection to a wide range of medium-to-heavy-duty German equatorial mounts capable of supporting its weight.

    C9.25 vs. C8: The "Goldilocks" Schmidt-Cassegrain

    For astronomers deciding between Celestron's iconic SCTs, the C9.25 often represents the ideal middle ground. While the 8" SCT is lighter, the C9.25 provides a substantial performance upgrade without the demanding weight and mounting requirements of an 11" model.

    • Celestron C8 Advantage: At just 12.5 lbs, the C8 is the ultimate in portability and can be carried by lighter, less expensive mounts.
    • Celestron C9.25 Advantage: The C9.25's larger 235mm aperture collects 33% more light than an 8" (203mm) mirror. This translates to significantly brighter images of faint objects and higher resolving power, making it a more capable instrument for both visual observation and astrophotography.

  • What kind of mount is required for the Celestron C9.25 OTA?

    The C9.25 weighs 20 lbs and comes with a CGE-style (3-inch) dovetail bar. You will need a German equatorial mount with a CGE or dual Losmandy/CGE saddle plate and a payload capacity of at least 30 lbs for visual use, or 40 lbs for stable astrophotography.

    How does the C9.25's 36% central obstruction affect views?

    The 36% obstruction by diameter is typical for a Schmidt-Cassegrain design and results in a slight reduction in peak contrast compared to an unobstructed refractor of the same aperture. However, the C9.25's large aperture and StarBright XLT coatings still deliver exceptionally bright, high-resolution images that far surpass what a smaller refractor can show, especially on deep-sky objects.

    What accessories do I need to use the C9.25's Fastar capability?

    To image at f/2, you will need a Fastar lens assembly (sold by third-party manufacturers like Starizona or Celestron) and a compatible astronomy camera with a small, round body that fits in the front of the telescope without blocking too much of the aperture.

    Can the C9.25 clearly resolve the Cassini Division in Saturn's rings?

    Absolutely. The C9.25's 0.49 arc second Dawes resolution is more than sufficient to cleanly resolve the Cassini Division on any night with average seeing conditions. On a night of steady seeing, you can expect to see cloud bands on both Saturn and Jupiter, and potentially even the Great Red Spot.

    Is the C9.25 a good choice for imaging small galaxies like the Whirlpool Galaxy (M51)?

    Yes, the C9.25 is an excellent instrument for galaxy imaging. Its long focal length of 2350mm provides the ideal image scale to capture detail in smaller targets like the Whirlpool Galaxy (M51) or the Sombrero Galaxy (M104) without requiring aggressive Barlow lenses or power-mates.

    Why is the C9.25 often called the "Goldilocks" telescope?

    The C9.25 earns this title because it offers a near-perfect compromise between performance and portability. It provides a 33% increase in light-gathering power over an 8" SCT, making a visible difference at the eyepiece, while still weighing only 20 lbs—making it far more manageable than a much heavier 11" SCT.

  • Optical Design Schmidt-Cassegrain
    Aperture 235mm (9.25")
    Focal Length 2350mm (93")
    Focal Ratio f/10
    Optical Coatings StarBright XLT
    Highest Useful Magnification 555x
    Lowest Useful Magnification 34x
    Limiting Stellar Magnitude 14.4
    Resolution (Rayleigh) 0.59 arc seconds
    Resolution (Dawes) 0.49 arc seconds
    Light Gathering Power 1127x (Compared to human eye)
    Secondary Mirror Obstruction 85mm (3.35")
    Obstruction by Diameter 36%
    Obstruction by Area 13%
    Optical Tube Length 559mm (22")
    Optical Tube Weight 20 lbs (9.07 kg)
    Dovetail CGE Dovetail Bar
    Included Eyepiece 25mm (94x Magnification)
    Finderscope 6x30
    Star Diagonal 1.25"

    • 9.25" Schmidt-Cassegrain OTA

      × 1

    • 25mm Eyepiece (1.25")

      × 1

    • 6x30 Finderscope

      × 1

    • 1.25" Star Diagonal

      × 1

    • Front and Rear Dust Caps

      × 1

  • Celestron 2-Year Telescope Warranty