151PHQ is a long-focal-ratio, flatfield astrograph newly launched after 130PHQ and also the biggest refractor of Sharpstar products till now. Instead of buying extra flatteners, calculating the backfocus of the flattener, or making a tedious connection to match the distance, astrophotographers can simply equip it with any possible imaging devices, make the target stay at the focus, and then the whole optical system is perfect for imaging.