For CCD imaging with the 35mm-size imaging chip of the STL-series cameras, this fully multicoated 8 oz. four-lens system increases the diffraction-limited field of an f/4.5 system by 36x in area and reduces the field edge coma by 75%-95%. The Paracorr essentially makes an f/4 scope perform like an f/8 in terms of image quality, while still keeping the shorter exposure times and wider field of the faster f/4 focal ratio (actually f/4.6 with the 1.15x focal length/focal ratio gain factored in). Stars at the edge of the field change from comet-shaped comatic flares to points of light, so that stars look virtually the same anywhere in the negative. Faint stars at the edge of the field do not fuzz out to invisibility due to coma and field curvature, but show as tightly focused points of light as much as six times smaller than their size without the Paracorr.

The Paracorr STL-series Photographic has wide threads that attach directly to the body of SBIG STL-series cameras at the optimum flange distance. Large internal lenses minimize vignetting on large CCD chips while achieving the flat and sharp fields the Paracorr is famous for with fast Newtonians. The Paracorr’s 2” barrel fits all standard 2” focusers.