Sorry its the VC200L that I was referring to details below
Vixen's unique catadioptric design features a high precision sixth order aspherical primary mirror, a convex secondary mirror and triplet corrector lens. VISAC is an abbreviation for Vixen's Six-Order Aspherical Cassegrain. The primary mirror is held by a retaining ring, instead of hooks to decrease flare and enhance contrast. The VC 200L is an 8" f/9.0 highly corrected, highly specialized telescope for astro imaging. The VISAC provides high-definition star images to the edge of a wide viewing field and offers exceptionally outstanding performance in astrophotography.Even at the edge of the 35mm film format (larger CCD chips) stars are sharp ( smaller than 15 micrometers) This is smaller than the resolution of fine quality CCD cameras, which means that the telescope does not limit the image quality.With its elaborate aspherical optical design it achieves an excellent image correction throughout the large illuminated field. (42mm diameter fully illuminated)
http://www.vixenoptics.com/reflectors/VC200L.jpg