Celestron 11' Rowe-Ackermann Schmidt Astrograph RASA Optical Tube, Version 2

Fast, wide-field 11' f/2.2 optical design with rare-earth glass for images free of false color, coma, and field curvature Large 43.3mm optimized image circle maintains pinpoint stars to the far corners of even the largest astroimaging sensors, while the usable field extends even further to 52mm for larger format sensors New Ultra-Stable Focus System (USFS) minimizes focus shift and mirror flop Integrated air-cooling system features a quiet, high-output 12V Mag Lev fan and vents with mesh filters to prevent dust ingress Common camera adapters (T-thread and M48) included for easy attachment to popular CCD and DSLR cameras