Celestron CGX 800 RASA Telescope

The 8" RASA: f/2.0 Speed for Deep-Sky Imaging in Seconds

The core of this imaging system is the 8" RASA's incredibly fast f/2.0 focal ratio. This optical speed allows your camera to gather immense amounts of light in a fraction of the time required by f/7 or f/10 systems, enabling you to capture deep, high-signal images with sub-exposures so short that autoguiding often becomes unnecessary. The optical design is corrected over a wide 400-800 nm spectral range, ensuring tight, chromatic-aberration-free stars from broadband imaging.

This speed transforms the imaging process. Instead of waiting minutes for a single frame, you can stack dozens of short exposures to build a deep, clean master image. Combined with live-stacking software, this setup delivers a near-real-time viewing experience, revealing detail in faint nebulae and galaxies that surpasses what can be seen visually through much larger telescopes.

Engineered for Imaging: A 22mm Flat Field and Ultra-Stable Focuser

Designed exclusively for astrophotography, the 8" RASA delivers a flat, coma-free 22mm image circle optimized for today's smaller-format CMOS and mirrorless cameras. Stars remain pinpoints across the field, with a spot size of less than 4.6 μm RMS. The system maintains 93% illumination at 11mm off-axis, preventing significant vignetting on your target sensor.

To eliminate image shift, Celestron developed the Ultra-Stable Focusing System, which uses a precision linear ball bearing to support the primary mirror. This design prevents the lateral movement that can ruin an exposure during focusing or slewing. Additional imaging-centric features include an integrated air-cooling system to speed thermal stabilization and a removable 46mm optical window that can be replaced with a custom Light Pollution Imaging Filter to maintain peak optical performance.

CGX Mount: 55 lb Capacity and a Vibration-Free Foundation

The CGX mount provides the rigid, high-precision foundation the RASA demands. Its 55 lb instrument capacity handles the 17 lb optical tube with ease, leaving ample margin for a camera, filter wheel, and other accessories without compromising stability. The heavy-duty tripod is built with 2" diameter steel legs, creating an exceptionally wide and stable footprint that damps vibrations quickly.

The mount head is engineered to hold the payload closer to the Right Ascension axis, reducing torque and improving tracking stability. With a latitude adjustment range of 3° to 65°, the CGX is a capable platform for imagers from the equator to high northern or southern latitudes.

Precision Tracking: DC Servo Motors and the 40,000-Object NexStar+ System

At the heart of the CGX are low-cog DC servo motors with integrated optical encoders. This system delivers smooth, quiet operation with the accuracy needed for unguided short-exposure imaging. A belt-and-pulley system minimizes backlash, ensuring immediate response when guiding or slewing. The built-in Periodic Error Correction allows you to train the mount to compensate for the worm gear's minor mechanical imperfections, further tightening your tracking for longer exposures.

The included NexStar+ hand control puts a database of over 40,000 celestial objects at your fingertips. For more advanced control, the included CPWI Telescope Control Software allows you to operate the mount from a PC, offering a graphical planetarium interface and advanced alignment modeling for unmatched pointing accuracy.

RASA 8" vs. RASA 11": Portability Meets Wide-Field Power

The 8" RASA offers the core benefits of the RASA design in a significantly more portable package than its larger sibling, the RASA 11.

• Weight and Portability: The 8" RASA OTA weighs just 17 lbs, making it easy to transport and set up at a dark-sky site. The RASA 11 OTA, by comparison, is over 40 lbs, requiring a more substantial mount and effort to manage.
• Image Circle and Camera Compatibility: The 8" RASA is optimized with a 22mm image circle for smaller CMOS and mirrorless cameras. The RASA 11 offers a much larger image circle suitable for full-frame and large-format CCD cameras.
• Mount Requirements: The lightweight 8" RASA is perfectly matched to the 55 lb capacity of the CGX mount. The larger RASA 11 requires a mount in the CGX-L or CGE Pro class. For imagers seeking an affordable and transportable entry into ultra-fast, wide-field astrophotography, the 8" RASA is the clear choice.