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12020 8" ROWE-ACKERMAN SCHMIDT ASTROGRAPH WITH CGEM MOUNT

$4,149.95
SKU:
12020
Weight:
58.0000 LBS
Shipping:
Calculated at checkout
Quantity:

Product Description

CGEM II 800 ROWE-ACKERMAN SCHMIDT ASTROGRAPH TELESCOPE

 
  • 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.
  • Internal filter mount – seamlessly accommodates a Light Pollution Imaging Filter into the optical path.
  • 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.
  • The CGEM II, with its 40 lb. 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.

INCLUDES THESE CELESTRON TECHNOLOGIES

 

COMPATIBLE WITH

This kit combines the 8” Rowe-Ackermann Schmidt Astrograph (RASA) with the CGEM II EQ mount. Simply add a camera and this package offers everything you need to take spectacular images of wide-field deep sky objects.

 

RASA Performance Made for Everyone

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.

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.

 

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. The telescope does not work with standard DSLR cameras. It is optimized for sensors with up to a 22mm diagonal, but performs well with sensors up to 32mm diagonal. The APS-C sized sensors used in many mirrorless cameras are a good choice. 42mm full frame sensors will also work, but performance will be poor at the edges of the sensor and field illumination will be reduced. Additionally, we do not recommend pairing RASA 8 with any camera body more than 4” in diameter. See the chart below to determine if your camera is compatible with RASA 8.

 

CameraCompatible with RASA 8?Adapter required
Astronomical CMOS/CCD camera with C-mount Yes C-mount adapter (included)
Astronomical CMOS/CCD camera with M42-thread mount Yes M42 adapter (included) with M42 extension tubes (not included)
Astronomical CMOS/CCD camera with other mount Yes Custom camera adapter
Canon mirrorless with APS-C sensor Yes

Canon mirrorless adapter

(sold separately)

Sony mirrorless with APS-C sensor Yes

Sony mirrorless adapter

(sold separately)

Canon mirrorless with full frame (42mm) sensor Yes, but not optimized across the full sensor

Canon mirrorless adapter

(sold separately)

Sony mirrorless with full frame (42mm) sensor Yes, but not optimized across the full sensor

Sony mirrorless adapter

(sold separately)

DSLR No --

 

Unique Optical Design

RASA’s optical design is patented (US 2016/0299331 A1). The design consists of a Schmidt corrector, primary mirror, lens group, and optical window. The lens group contains 4 elements and utilizes rare-earth elements. Unlike many telescopes that only perform well over the visible spectrum (400-700nm), the 8” RASA’s optics are designed to perform over a wider spectral range, from 390-800nm. This allows more of the light emitted from the astronomical object to be sharply focused in the image.

With many imaging systems, adding an extra piece of flat glass such as a filter does not change optical performance. However, that is not the case with super-fast optical systems like the RASA. Our engineers addressed this by designing the RASA with a removeable optical window, so you can maintain peak optical performance if a filter is added or if a camera has its own optical window. Celestron offers a Light Pollution Imaging Filter designed specifically for the 8” RASA, which mounts in place of the optical window.

All refractive optical surfaces are coated with StarBright XLT coatings, while the primary mirror uses enhanced aluminum coatings. This maintains high light transmission through the entire optical system.

When compared with “Hyperstar SCT” systems, the RASA 8 provides better optical performance and field illumination.

CGEM II: An Excellent Platform for RASA

CGEM II is a sturdy equatorial mount capable of rigidly supporting the 8” RASA. Its 40-lb. load capacity can handle the 17-lb. optical tube with ease, leaving lots of capacity to spare for your camera and any accessories. The heavy-duty adjustable height tripod has 2” diameter steel tripod legs with graduated markings that make it easy to extend the legs to the same height. The 8” RASA connects directly to the CGEM II with its CGE dovetail mounting bar.

The mount is packed with functionality and conveniences that make imaging with the 8” RASA easy. The fully computerized mount will automatically “GoTo” any of the 40,000+ astronomical objects selected from the NexStar+ hand controller’s database and automatically track the object as it appears to move across the night sky.

Designed with imaging in mind, the CGEM II motor drive system accurately tracks during an exposure. At the heart of the system are low cog DC servo motors with integrated optical encoders. The low cog design helps the motors run smoothly, while the integrated optical encoders provide accuracy. The motors turn steel worm gears, which are supported by precision bearings, against brass worm wheels. These components also help to make the motor drive system operate smoothly and accurately.

 In summary, the CGEM II and RASA 8 work well together to attain stunning imaging results with minimal hassle. It’s the perfect kit for those who want to take the next step into deep-sky astroimaging.

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