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Celestron 11" f/2.2 Rowe-Ackermann Schmidt Astrograph Telescope (OTA only)  - The Imaging Flagship from Celestron
Celestron 11" f/2.2 Rowe-Ackermann Schmidt Astrograph Telescope (OTA only)

Celestron 11" f/2.2 Rowe-Ackermann Schmidt Astrograph Telescope (OTA only) - The Imaging Flagship from Celestron

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Your Price: CAD4,669.00
Retail Price:CAD4,749.00

Your Savings:CAD80.00(2%)

Usually ships in 5-7 business days
Part Number:91075

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Camera Adapters and Imaging Accessories
Imaging Cameras/Autoguider
Barlow Lenses
Eyepiece and Filter Kits
Filters
Miscellaneous
“I don’t get it. What do you look through?”

This might be the most common question people ask when you unpack your new Celestron Rowe-Ackermann Schmidt Astrograph (RASA). It’s not only missing something that comes with virtually every telescope ever produced . . . an eyepiece . . . it doesn’t even have a place to put an eyepiece. That’s because the 620mm focal length f/2.22 Celestron 11” RASA is strictly a deep space imaging scope and cannot be used visually.

But what an imaging scope! It has a huge 70mm image circle that can handle full frame DSLRs and the largest sensor size CCD cameras with minimal vignetting. It provides a proven Schmidt corrector optical system with a built-in 4-element rare earth corrector lens that keeps the images free of coma, field curvature, and false color. The optical quality and spot size across the entire image circle are unprecedented for an astrograph in this price range – or even that of a much more expensive instrument.

Its fast, wide field, f/2.22 optics give you two huge advantages over traditional f/10 catadioptric imaging scopes (even those using an optional f/6.3 or f/7 focal reducer). Those advantages? Better apparent tracking due to the image scale, plus shorter exposure times due to the speed of the optics. That means you can create better-looking deep space images in a fraction of the time it used to take, even without using an autoguider.

The Celestron RASA concept was to modernize the Celestron Schmidt camera, an instrument that had a loyal following, as its very fast focal ratio allowed amateur astrophotographers to produce wide field deep space images in the 1970s. Schmidt cameras could produce great images, but they wre and imaging scope only a really hard-core astrophotographer could love.

Those Schmidt cameras used a single frame of 35mm film, cut from a roll of film. You flexed the chip of film in total darkness (being careful not to touch the emulsion side) to fit snugly into a curved holder that matched the camera’s curved focal plane, then loaded it into the camera by feel inside a black cloth bag to avoid image-spoiling stray light. You manually guided your scope during the entire exposure, keeping your eye glued to the crosshairs of an illuminated reticle eyepiece so your stars wouldn’t turn into elongated squiggles. Finally, after a sometimes multiple hour single exposure, you tediously processed the small chip of film in your own darkroom before you could even begin to see if you had captured a usable image.
 
 

The 11" f/2.2 Rowe-Ackermann Schmidt Astrograph Telescope from Celestron is specifically designed for astrophotography and astroimaging with a large 11" aperture and fast f/2.2 focal ratio. The OTA is being offered by itself without a mount, and comes with a Celestron CGEM-style dovetail plate for use on compatible mounts and tripods. Using the improved StarBright XLT multi-coating system, light transmission is increased throughout the entire optical path with anti-reflection multicoated lenses, highly reflective multicoated mirrors, and 4-element rare-earth glass.

A 70mm imaging circle is made to cover today's large DSLR and CCD imaging sensors to capture full-frame shots. Its fast focal ratio reduces exposure times without sacrificing image quality, and gives the user more time for multiple shots of the same object for layering or with different filters, or to change subjects completely. A custom-designed 10:1 linear brass focuser enables very precise focusing to clearly resolve topographic details on the Moon, virtually remove comas and corona from distant stars, and reveal details of most other celestial objects in between. Since this OTA is designed as an imaging scope, a 42mm T-thread camera adapter and 48mm camera adapter are provided. Other adapters are available if required.

Optical Performance
  • 11" diameter aperture
  • 620mm focal length
  • Fast f/2.2 focal ratio
  • Proprietary StarBright XLT fully multicoated optical system
  • 4-element rare-earth glass for true color rendition without aberrations across the entire field of view
  • 70mm image circle captures pinpoint stars on today's large CCD and DSLR imaging chips
StarBright XLT Coating System
  • Multi-layer mirror coatings made from layers of aluminum, SiO2 (quartz), TiO2 (titanium dioxide), and Si02 (silicon dioxide)
  • Reflectivity is flat across the light spectrum, for both astrophotography/astroimaging and visual observation
  • Multi-layer anti-reflective coatings made from layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide)
  • High-transmission water white glass corrector lens with 97.4% light transmission
Use and Handling
  • Linear brass focuser-bearing reduces image shift
  • Dual-speed 10:1 FeatherTouch micro focus knob provides precise focusing
  • Heavy duty CGEM dovetail plate
Construction Details
  • 42mm T-thread and M48 camera adapters included for attachment to CCD and DSLR cameras
  • 12VDC MagLev fan reduces cool-down time and provides airflow
 
Optical Design
Rowe-Ackermann Schmidt
Aperture
11" (27.9 cm)
Focal Length
620 mm
Focal Ratio
f/2.2
Back Focus
2.2" (5.5 cm), from front lens assembly
Eyepiece Barrel Diameter
N/A
Diagonal
None
Finderscope
None
Tripod
None
Mount Type
CGEM dovetail plate
Power Requirement
12 VDC for fan operation
Length
33" (83.8 cm)
Weight
35 lb (15.9 kg)
 
Celestron 11" f/2.2 Rowe-Ackermann Schmidt Astrograph Telescope (OTA only)
  • 42mm T-Adapter
  • 48mm Camera Adapter
  • Limited Two-Year Warranty

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