The celestron nexstar 127 slt computerised telescope has a high quality 127 mm maksutov cassegrain and fully computerised altazimuth mount the nexstar 127 slt is powered by 8 aa user supplied batteries or an optional ac adapter 18778 the internal battery compartment provides power to the high precision servo motors for rigid low vibration performance while eliminating cord wrap issues associated with external battery packs with the nexstars ergonomically designed hand control the us