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Celestron 11" Rowe-Ackermann Schmidt Astrograph (RASA) Telescope

£3,925.00
SKU 91075

Availability: Immediate Dispatch

  • Rowe-Ackermann 11-inch f/2.2 optical design
  • Rare-earth glass for images free of false color, coma, and field curvature
  • 43.3 mm optimised image circle with pinpoint stars to the far corners of even the largest astroimaging sensors
  • 52 mm usable field for larger format sensors.
  • Custom engineered linear brass focuser bearing reduces image shift
  • Dual-speed 10:1 FeatherTouch Micro Focus Knob for precise focusing
  • Quiet, high-output 12V MagLev fan reduces cooldown time and blocks dust
  • Common camera adapters (T-thread and M48) included for easy attachment to popular CCD and DSLR cameras
Description

The Rowe-Ackermann Schmidt Astrograph builds on the legacy of Celestron’s Schmidt Camera, which allowed astrophotographers to produce images on film in the 1970s. This fast, wide-field f/2.2 astrographic system offers two huge advantages over traditional f/10 astroimaging: better apparent tracking and shorter exposures. That means you’ll create better-looking astroimages in a fraction of the time, even without the use of an autoguider. Celestron’s new Rowe-Ackermann Schmidt Astrograph will allow you to capture impressive deep-sky astroimages easier than ever before and it makes the perfect companion to today’s top DSLR or astronomical CCD cameras. 

Today, with CCD sensor sizes as large as film—or larger—the Schmidt Astrograph offers a 43.3 mm optimised image circle to capture pinpoint stars on the largest imaging chips. (Note: We previously published 70 mm which is actually the aperture of the last lens in the telescope. The optical design has not changed). Combine this large image circle with a focal length of just 620 mm and you have an instrument suitable for wide-field imaging, creating huge mosaics of the night sky, surveying, and even comet hunting.

Optical Performance
The Rowe-Ackermann Schmidt Astrograph features newly designed optics with 4-element rare-earth glass for images free of false colour and aberrations like coma and field curvature.

Celestron RASA Ray Diagram

The optical quality and spot size across the entire image circle is unprecedented for an astrograph in this price range—or even that of a much more expensive instrument. The design also provides minimal vignetting.


Advanced Features
Advanced features like a custom engineered linear brass focuser bearing and FeatherTouch Micro Focus Knob allow you to make the fine adjustments you need to capture the perfect shot. Meanwhile, a12V MagLev fan reduces cool-down time and provides optimal airflow through the dust filtered optical tube.

Rear of the RASA showing the fan and the Feathertouch focuser

Engineered as a complete astroimaging system, every component of the Rowe-Ackermann Schmidt Astrograph is optimised for peak performance with DSLR and astronomical CCD cameras. Down to the thickness of the glass used in the included fully-multicoated optical window or an optional imaging filter, every component of the system has been taken into careful consideration to work together seamlessly.

Specifications
OPTICAL TUBE INFO:
Optical Design Rowe-Ackermann Schmidt Astrograph
Aperture 279mm (11")
Focal Length 620mm (24.4")
Focal Ratio f/2.2
Central obstruction diameter 114mm (4.48") (41% of aperture diameter)
Light Gathering Power (Compared to human eye) 1588x
Resolution (Rayleigh) 0.49 arc seconds
Resolution (Dawes) 0.41 arc seconds
Image Circle 43.3mm (1.7") Ø , 4.0°
Useable field 52mm (2.04") Ø , 4.8° only minimal performance loss at edge of FOV
Wavelength range 400 - 700 nm
Spot size < 4.4 μm RMS across FOV
Optical Coatings StarBright XLT
Off-axis Illumination 83% at 21mm (.82") off-axis
Optical Window 68mm (2.67") Ø
Back focus with included camera adapter 55mm (2.16")
Back focus from top of threaded collar 72.8mm (2.86")
Optical Tube Aluminum
Optical Tube Length 838.2mm (33")
Optical Tube Diameter 330.2mm (13")
Focuser FeatherTouch microfocuser, coarse and fine focus
Finderscope Not included
Optical Tube Weight 43 lbs (19.5 kg)
Other Features Ventilation fan, dual dovetail mounting bars, mirror support clutches
Included items 42mm (1.65") T-thread camera adapter, 48mm (1.89") camera adapter, fan battery pack
Dovetail CGE Dovetail Bar

 

Gallery

Heart Nebula with RASA 11"

Spider Nebula with RASA 11"

Propeller Nebula with RASA 11"
M8, M20 and NGC6559 with RASA 11"
Orion Nebula with RASA 11"
Videos

Downloads

11" Rowe-Ackermann Schmidt Astrograph Manual

Whitepaper RASA

Camera Adapter requirements