Sky watcher explorer 150pds 150mm 6 f750 parabolic dual speed newtonian reflector optical tube assembly the new sky watcher explorer 150pds range of newtonian reflector incorporates the same superb mirror set as the explorer 150p black diamond series but with two significant advantages a dual speed 101 ratio focuser is now included for excellent focusing precision also the tube length has been slightly shortened to optimise performance for prime focus photographyeven better performanc