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Coma-free images from a standard SCT!
The Starizona SCT Corrector was named one of Sky & Telescope's Hot Products for 2012!
The Starizona SCT Corrector is a focal reducer and field flattener for standard Schmidt-Cassegrain telescopes. It converts the telescope from f/10 to f/7.5, resulting in a wider field and faster imaging. f/7.5 is nearly 1.8 times faster than f/10!
The field is optimized for a 35mm image circle. Spot sizes are up to 5 times smaller than the native telescope, and coma is completely eliminated. The result is much sharper stars across a large, flat field of view. A standard 2" mounting allows a variety of telescope attachment options.
The SCT Corrector has 90mm (3.5") of mechanical backfocus, accommodating a large variety of cameras and filter wheels. Spacers are required to set the exact backfocus distance and are available separately for a variety of cameras (see below).
Features
- 0.75x Focal Reduction
- 35mm Optimized Image Circle
- 2" Diameter
- 90mm Backfocus
- Threaded for 2" (48mm) Filters
- Fully Multi-Coated Optics
- Made in USA
Example Specifications (11" SCT)
- Focal Ratio: f/7.5
- Focal Length: 2100mm
- Corrected Field: 56 arcminutes
RMS Spot Size Comparison (11" SCT)
Above: A plot of the spot size across the field for an 11" SCT without the corrector (black) and with the corrector (blue). On-axis performance is equal, but even slightly off-axis, the spot size of an uncorrected SCT grows rapidly due to field curvature and coma. The corrected telescope has a very flat field with small spots all the way across the image.
Above: Comparison of the upper left corner of images from a Celestron 11" SCT and Canon EOS 7D camera. Each image is a 100% crop of the upper left corner of the frame. The pictures were taken through the same scope within minutes of each other using 5-second exposures at ISO1600. Compare the elongated comatic stars in the left image at f/10 to the perfectly round, smaller stars in the right image with the SCT Corrector in place.
Spot Diagram Comparison
Shown below are spot diagrams for a Celestron 11" SCT at the native f/10 focal ratio, with a standard Celestron f/6.3 focal reducer, and with the Starizona f/7.5 SCT Corrector.
Available Camera Adapters
- Atik
- Canon EOS
- Nikon
- QSI 500 Series
- SBIG ST-Series
- Starlight Xpress
- Custom adapters available--please contact us
Dimensions (without camera adapter)
- Diameter: 2.00" (50.8mm)
- Length: 1.85" (47mm) + 0.20" (5mm) thread
- Weight: 7.7 oz (218g)
Note that since the SCT Corrector is designed to correct the coma inherent in standard Schmidt-Cassegrain telescopes, it will not work properly with Celestron EdgeHD or Meade ACF optical systems.
 View the instruction manual for this product
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