Skywatcher offers a wide range of Newtonian telescopes under the brand name Explorer. The telescopes are available individually or in combination with a variety of mounts.
BD as in “black diamond”: the Explorer BD series of telescopes are very popular with amateur astronomers because they offer high-quality parabolic optics at a very reasonable price. Many amateur astronomers started with an Explorer BD, and many have remained true to their Newtonian to this day.
The Explorer PDS offer the same mirror optics, but are optimised for astrophotography: a more favourable focal position, thinner secondary mirror and an eyepiece with focus adjustment.