Description

• Flat field free of optical aberrations like field curvature, coma, astigmatism and chromatic aberration across an entire APS-C sensor.
• NEW Ultra-Stable Focus System – six precision sealed ball bearings virtually eliminate image shift.
• Integrated air cooling system –12V DC MagLev fan reduces cooldown time and provides optimal air flow while filtering out dust.
• Internal filter mount – seamlessly accommodates a Light Pollution Imaging Filter into the optical path.
• CGE dovetail mounting rail.
• Performs over a wider spectral range than most telescopes, from 390-800 nm, so more of the light passing through the astrograph is in sharp focus.

• Description

  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.

  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.

   

  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 Design		Rowe-Ackermann Schmidt Astrograph
  Aperture		203 mm (8 )
  Focal Length		400 mm (15.74 )
  Focal Ratio		f 2.0
  Central obstruction diameter		93 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 Circle		22 mm (.86 ) Ø, 3.15°
  Useable field		32 mm (1.26 ) Ø, 4.6°, only minimal performance loss at edge of FOV
  Wavelength range		390 – 800 nm
  Spot size		< 4.6 μm RMS across image circle
  Optical Coatings		StarBright XLT
  Off-axis Illumination		93% at 11 mm (.43 ) off-axis
  Optical Window		46 mm (1.81 ) Ø
  Back focus with included camera adapter		25 mm (.98 )
  Back focus from top of threaded collar		29 mm (1.14 )
  Optical Tube		Aluminum
  Optical Tube Length		628 mm (24.7 ) length, 235 mm (9.3 ) diameter
  Focuser		Ultra-Stable Focusing System
  Finderscope		Not included
  Optical Tube Weight		17 lbs (7.7 kg)
  Other Features		Air-cooling system, integrated filter mount
  Included items		M42 camera adapter, C-thread camera adapter, fan battery pack
  Dovetail		CGE Dovetail Bar

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