Celestron Advanced VX RASA 6"

The Celestron Advanced VX RASA 6: A Portable 152mm Imaging System

This system is engineered for astrophotographers who demand speed, a wide field, and portability. The 6" RASA optical tube weighs only 8.4 lbs, making it an easy load for the robust Advanced VX mount and leaving plenty of the 30 lb capacity for your camera and accessories. The entire package, with a total weight of 55.4 lbs, is designed to be a grab-and-go solution, perfect for trips to dark-sky sites or for setting up quickly in your backyard.

The RASA 6" is an imaging-only telescope; it is not designed for visual use. Its purpose is to act as a powerful telephoto lens for your astronomy camera, capturing faint deep-sky objects with incredible efficiency. RASA technology has been relied on for space surveillance and satellite tracking since it debuted in 2014, and the RASA 6 collects more light and provides higher resolution than the refractors in its class.

RASA Optics: A 4-Element Flat-Field Schmidt Astrograph

The patented Rowe-Ackermann Schmidt Astrograph (RASA) optical design delivers professional-level performance. Light passes through a Schmidt corrector, reflects off a primary mirror, and then travels through a specialized three-element lens group made with rare-earth glass. The design gives a flat field for sharp stars from edge to edge, with spot sizes smaller than 1.5 μm RMS across the image circle.

All optical surfaces feature Celestron's StarBright XLT coatings, for maximum light transmission and field illumination, and the optics are designed for 400 to 700 nm. The system achieves a Dawes resolution of 0.76 arc seconds and gathers 472 times more light than the naked eye. The central obstruction is 77mm, off-axis illumination is 91% at 8mm off-axis, and the RASA design provides better overall performance and field illumination than a Schmidt-Cassegrain in the Fastar-style configuration.

f/2.2 Speed and 3.76° Field: Capturing the Sky in Minutes

The defining feature of the RASA is its incredible f/2.2 focal ratio. It dramatically shortens exposure times, so faint objects can be imaged in short exposures. With a sensitive camera and live-stacking software on your laptop, bright, detailed images appear on screen in just a few short exposures, for an almost real-time imaging experience.

Paired with a 335mm focal length, the RASA 6" covers a 3.76° field on a 22mm sensor diagonal while delivering sub-arcsecond resolution, in Celestron's words.

A 22mm Usable Field and 17.5mm Back Focus

The RASA 6" is optimized for cameras with sensors up to a 22mm diagonal, which corresponds to its usable field of 3.76°. The manual says the design is optimized for sensors up to 16mm diagonal and still performs well up to 22mm, with reduced field illumination in the corners. Because the camera sits in front of the optics, cylindrical cameras under 75mm outer diameter work best, and many astronomical and "HyperStar-compatible" CMOS cameras are well suited.

The system is engineered for a precise back focus of 17.5mm, measured from the top flat surface of the included camera adapter. Missing it may degrade performance at the edges of the sensor, particularly with larger sensors. The included adapter makes it easy to attach any camera with standard M42 T-threads, and optional M42 extension rings place the sensor correctly if your camera's backfocus is shorter than 17.5mm; cameras with sensors recessed more than 17.5mm are not compatible. Due to their large obstruction and long backfocus, DSLR cameras are not compatible.

Imaging Features: 12V Cooling, Focuser, and Integrated Filter Drawer

Designed for the modern imager, the RASA 6" includes practical features to streamline your workflow. A 12V DC MagLev fan actively cools the primary mirror, helping the optics reach thermal equilibrium with the ambient air for the sharpest possible images. The fan pulls air through mesh-covered vents, keeping the internal optics dust-free.

Focusing is achieved with a standard Schmidt-Cassegrain style focuser that moves the primary mirror. An integrated filter drawer located in the optical path accepts both 2" and 1.25" filters, allowing you to easily switch between light pollution, narrowband, or color filters. The system includes a removable 2" clear filter, which maintains the optical system's f/2.2 performance when no other filter is in use. When you swap in an imaging filter, no extra glass is added to the light path, preserving image quality.

Advanced VX Mount: A 30 lb Capacity GoTo German Equatorial Platform

The Advanced VX (AVX) mount is a stable and reliable platform for the RASA 6" astrograph. With an instrument load capacity of 30 lbs, it easily supports the 8.4 lb optical tube along with a camera, autoguider, and other accessories. The mount head weighs 17 lbs and is supported by a sturdy tripod with 2" diameter stainless steel legs.

DC servo motors provide smooth and accurate tracking, with nine slew speeds up to 4° per second. The mount features permanently programmable Periodic Error Correction (PPEC), and its latitude adjusts from 7° to 77°.

NexStar+ and CPWI: A 40,000+ Object Database with Advanced Mount Modeling

Control of the Advanced VX mount is handled by the included NexStar+ hand control, giving you access to a database of over 40,000 objects. For more powerful control from a PC, the system includes Celestron's PWI (CPWI) Telescope Control Software. Co-developed with PlaneWave Instruments, CPWI provides a graphical planetarium interface and features PointXP advanced mount modeling, allowing you to add over 100 points to your alignment model for exceptional pointing accuracy.

The mount is equipped with an autoguide port, two AUX ports for accessories, and a USB port on the hand control for direct connection to your computer. CPWI integrates with ASCOM, so a wide range of third-party applications can control the mount, and it can save and reload your alignment and park the scope.

A Complete 55.4 lb Grab-and-Go Kit with All-Star Polar Alignment

This system is designed for quick setup and alignment. The mount features Celestron’s All-Star Polar Alignment procedure, which allows you to use any bright star to achieve an accurate polar alignment, even if you don't have a clear view of Polaris. This gets you imaging faster and with greater tracking precision.

The ultra-fast f/2.2 optics significantly reduce the demands on tracking precision. Because it allows much shorter sub-exposures, you will not need an autoguider in many instances. The entire kit, weighing 55.4 lbs, breaks down into manageable components for easy transport and setup at your favorite dark-sky location.

Solar Warning: Never look directly at the Sun with the naked eye or with an optic (unless you have the proper solar filter). Permanent and irreversible eye damage may result. Never use your optic to project an image of the Sun onto any surface. Internal heat build-up can damage the optic and any accessories attached to it. Never leave your optic unsupervised. Make sure an adult who is familiar with the correct operating procedures is with your optic at all times, especially when children are present.