Celestron

8” ROWE-ACKERMANN SCHMIDT ASTROGRAPH (RASA8)

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Your Price: $1,981.05
SKU:
91073
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Product Overview

Capture spectacular wide-field deep sky images in seconds with Celestron’s new portable astrograph, the 8” Rowe-Ackermann Schmidt Astrograph (RASA). This incredibly fast f/2.0 system is the perfect companion to today’s color astronomical CMOS cameras, smaller CCD cameras, and mirrorless cameras. Thanks to its fast focal ratio and patented optical design, you can produce sharp, detailed images and, in many cases, skip the autoguider completely. Weighing in at just 17 pounds, it’s easy to transport your 8” RASA to the most remote dark sky locations.

RASA Performance Made for Everyone

The 8” RASA is an imaging telescope that delivers a flat field without optical aberrations for razor sharp stars across a wide field of view. It can capture stunning deep-sky astronomical images without the challenges typically presented by longer focal length instruments at a fraction of the cost of those systems.

The latest addition to the RASA family, this 8” version is a much more portable and affordable version of the heralded RASA 11, which was introduced to much acclaim in 2014. With the 8” RASA joining the lineup, a wider range of astroimagers can enjoy the benefits of the RASA design. It has many of the same thoughtfully designed features as its “big brother” RASA 11, including the integrated air-cooling system, internal filter mount, and sturdy CGE dovetail mounting bar.

Purely designed for imaging, the 8” RASA cannot be used visually. The prime focus focal plane is located at the front of the optical system, so it cannot accommodate a traditional eyepiece.

Shorter Exposure Times and Virtual “Real-Time” Observing

Since it is an F/2.0 optical system, imagers can use shorter exposure times to capture detail in faint objects. When combined with sensitive cameras and the proper “live stacking” software, the 8” RASA can provide an almost real-time observing experience. View images on a computer instantly that are brighter and more detailed than can be seen in much bigger telescopes with the naked eye.

Because shorter exposure times are possible, your equatorial mount won’t need to accurately track over extended periods. The 8” RASA’s relatively short 400mm focal length also lessens equatorial tracking demands. In many cases, autoguiding will not be required. Weighing only 17 lb, this optical tube pairs perfectly with a wide variety of mounts.

Ultra-Stable Focus System

With the launch of the 8” RASA, Celestron is unveiling a new focuser design that mitigates lateral movement of the primary mirror when focusing, slewing, or tracking with the astrograph. Focusing is easier, more accurate, and more stable than ever. The key to the Ultra-Stable Focus System is two sets of precision bearings that are precisely aligned and tested during assembly to ensure optimal results.

Built for Today’s Latest Cameras

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. It is optimized for sensors with up to a 22mm diagonal, but still performs well with larger (up to 32mm diagonal) sensors. As such, it works well with APS-C sized sensors used in many mirrorless cameras.

Camera adapters to connect C-mount cameras and cameras which mount with M42 threads are included. Celestron offers optional adapters to connect your 8” RASA to Sony or Canon mirrorless cameras.

Specifications

OPTICAL TUBE INFO:
Optical DesignRowe-Ackermann Schmidt Astrograph
Aperture203 mm (8")
Focal Length400 mm (15.74")
Focal Ratiof/2.0
Central obstruction diameter93 mm (3.66") (46% of aperture diameter)
Light Gathering Power (Compared to human eye)843x
Resolution (Rayleigh)0.68 arc seconds
Resolution (Dawes)0.57 arc seconds
Image Circle22 mm (.86") Ø, 3.15°
Useable field32 mm (1.26") Ø, 4.6°, only minimal performance loss at edge of FOV
Wavelength range390 - 800 nm
Spot size< 4.6 µm RMS across image circle
Optical CoatingsStarBright XLT
Off-axis Illumination93% at 11 mm (.43") off-axis
Optical Window46 mm (1.81") Ø
Back focus with included camera adapter25 mm (.98")
Back focus from top of threaded collar29 mm (1.14")
Optical TubeAluminum
Optical Tube Length628 mm (24.7") length, 235 mm (9.3") diameter
FocuserUltra-Stable Focusing System
FinderscopeNot included
Optical Tube Weight17 lbs (7.7 kg)
Other FeaturesAir-cooling system, integrated filter mount
Included itemsM42 camera adapter, C-thread camera adapter, fan battery pack
DovetailCGE Dovetail Bar

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