Celestron CGEM II 8" Rowe-Ackermann Schmidt Astrograph Telescope

The Celestron 8” Rowe-Ackermann Schmidt Astrograph (RASA) with CGEM II EQ Mount is an imaging-focused telescope package designed to make wide-field deep-sky astrophotography more accessible. Add a compatible camera, and you have a complete imaging platform built around Celestron’s exceptionally fast f/2.0 RASA optical system and a computerized equatorial mount.

RASA Performance Made for Everyone

The 8” RASA is designed to capture wide-field deep-sky images in seconds, making it particularly well suited to modern color astronomical CMOS cameras, smaller CCD cameras, and mirrorless cameras. Its exceptionally fast f/2.0 focal ratio allows the system to gather light rapidly, while its patented optical design is engineered to produce sharp, detailed astronomical images. The fast optical system can also reduce the demands placed on your imaging setup. In many cases, the RASA can allow you to skip the autoguider completely, simplifying the equipment required for imaging while maintaining the ability to capture detailed deep-sky photographs. At just 17 pounds, the 8” RASA is designed with portability in mind. Its manageable weight makes it easier to transport the astrograph to remote dark-sky locations, allowing you to take advantage of darker observing environments without having to work with a substantially heavier imaging telescope.

The RASA’s imaging-specific optical design delivers a flat field without optical aberrations, helping produce razor-sharp stars across a wide field of view. This combination of wide-field coverage and sharp imaging makes the 8” RASA particularly suited to deep-sky astronomical photography. Compared with longer-focal-length imaging instruments, the RASA is designed to capture deep-sky images while avoiding some of the challenges associated with longer focal lengths. Its combination of fast optics, wide-field imaging, portability, and simplified guiding requirements provides an imaging-focused alternative to more demanding long-focal-length systems. The 8” RASA also incorporates several practical design features shared with the RASA 11, including an integrated air-cooling system, internal filter mount, and sturdy CGE dovetail mounting bar. These features complement the astrograph's imaging-focused design and help create a purpose-built platform for deep-sky photography. The CGEM II EQ mount completes the package, providing the equatorial mounting platform for the 8” RASA. Together, the RASA optical system and CGEM II create a dedicated setup for astronomers who want to pursue wide-field deep-sky imaging with a fast, portable astrograph.

Important: The 8” RASA is designed purely for imaging and cannot be used for visual observation. Its prime-focus focal plane is located at the front of the optical system, so it cannot accommodate a traditional eyepiece.

Features

• Flat field free of optical aberrations like field curvature, coma, astigmatism and chromatic aberration across an entire APS-C sensor.
• Unlike the larger RASAs that work with DSLR and large CCD cameras, the 8” model was designed with color astronomical CMOS cameras, smaller CCD cameras, and mirrorless cameras in mind. The telescope does not work with standard DSLR cameras.
• Ultra-Stable Focus System – precision linear ball bearing virtually eliminates image shift.
• Internal filter mount – seamlessly accommodates a Light Pollution Imaging Filter into the optical path.
• Performs over a wider spectral range than most telescopes, from 400 - 800 nm, so more of the light passing through the astrograph is in sharp focus.
• The CGEM II, with its 40 lbs load capacity, is the latest update to the venerable CGEM mount and provides a sturdy and rigid platform for the fully-loaded RASA 8.
• The drive system, consisting of low cog DC Servo motors with integrated optical encoders, steel worm gears supported by precision sealed bearings, and brass worm wheels, ensures smooth and accurate slewing and tracking.
• Proven NexStar+ computerized telescope control technology supports functions to address imagers’ needs, such as All-Star Polar Alignment, Permanent Periodic Error Correction (PPEC), and adjustable tracking through meridian.