BCelestron Advanced VX 11" Schmidt-Cassegrain Telescope ReviewbP PP Celestron Advanced VX 11" Schmidt-Cassegrain Telescope P11” (2800mm) f10 Schmidt-Cassegrain includes StarBright XLT coatings for better light transmissionP41 more light gathering than a 9.25” telescopeP9x50 optical finderscope for locating alignment starsPInteger gear ratios and permanently programmable Periodic Error Correction eliminates recurring track errors from the worm gear.