M101 taken by Justin P. with a C11 and the Large Format Corrector
Starizona's SCT Corrector has been an incredibly popular focal reducer and coma corrector, giving astrophotographers with standard Schmidt-Cassegrain telescopes an improved optical system and wider field of view, with increased photographic speed. Starizona now offers a large-format version, the SCT Corrector LF, designed to cover full-frame (35mm format) sensors.
The SCT Corrector LF is designed for Celestron 11" and 14" standard SCTs. Designed to thread directly onto the large 3.29" threads on the rear cell of C11 and C14 telescopes, the larger optical elements of the SCT Corrector LF minimize the vignetting over large sensors. Remaining vignetting over a large field is minimal and limited only by the telescope baffles, which are designed for a slower focal ratio; but this vignetting is easily removed by using flat field images. Sharpness is excellent over a 42mm diagonal, with spots sizes up to 9x smaller than the native telescope! The focal ratio is reduced to f/7.2 on the C14 and f/7 on the C11, for a speed increase of 2.1x and 1.9x, respectively.
The SCT Corrector LF is designed to increase the available backfocus compared to Starizona's standard SCT Corrector. Backfocus is 146, accommodating a variety of accessories. The rear threads on the SCT Corrector LF are the same 3.29" threads as on the rear cell of the C11 and C14 telescopes, so standard accessories are easily attached.
Above: Spots sizes compared for a native C14 at f/11 versus a C14 at f/7.5 with the SCT Corrector LF. Each small square in the diagram is 40 microns. The RMS spot size at the edge of the field for the native C14 is 106 microns and the SCT Corrector LF is just 13 microns!
- Focal Ratio: f/7
- Focal Length: 1960mm
- Focal Ratio: f/7.2
- Focal Length: 2560mm
- Image Circle: 42mm
- Mechanical Backfocus: 146mm from top of mounting threads
- Maximum Diameter: 3.5"
- Overall Length: 2.7" (length added from normal mounting threads is 2.3")
- Mounting Thread: Standard C11/14 3.29"-16tpi thread
- Weight: 1.6 lbs (730g)
- Fully AR coated optics
- Made in USA