This telecompressor was designed specifically for systems with well corrected optics and flat fields such as can be obtained from apochromatic refractors and the new coma free and correctly named LX400-ACF telescopes. The speed of a f/8 telescope would be increased to f/5.6 with this reducer and the optics would still be nearly diffraction limited. This four-element system also maintains the parfocality of the telescope since these types of telescope have more limited focus compared to SCTs. The image field is highly corrected to 18mm diameter so that large format CCD cameras can be used. The performance of this reducer would be impaired if used with a SCT type telescope.
The Ultra WideField 0.7XL is a new coupler from Optec and is designed specifically to speed up the focal ratios of highly corrected telescope systems. This design assumes that the image formed by the telescope is reasonably flat and aberration free. If so, the resulting image will also be highly corrected and nearly parfocal with the original image. Optimized for an f/8, the Ultra WideField 0.7XL will work for any focal ratio in the range of f/5.6 to f/20. The field is highly corrected up to 18mm in diameter and would work well even with larger fields with only slight degradation near the corners.
Like the other reducers in the NextGEN series, all surface have a broadband multilayer coating optimized for the 450 - 650 nm pass band of the optic. Filter mounted in front as with the IFW are compatible. In fast systems, it is always better optically to mount the filters in front of any reducer optic to keep the incoming rays closer to being normal (collimated) to the filter surface.
The Ultra WideField 0.7XL has been redesigned and improved in late 2006 and now has a much longer back focus distance and uses the same mounting plate adapters as the 0.33X and 0.50X models. This allows use of this reducer with SBIG cameras having the CFW-8/10 filter wheels mounted.
|Name||Optec - NextGEN UltraWidefield 0.7X Parfocal Telecompressor Kit.|