This Hugh Eyepiece Lens is, One Piece of BK-7 Optical Crown...Not Cheap.I recommend--Used for a Dobson..Wide-angle Low powered Scope...Bigger the scope, the Better !!
This Lens is a Symmetrical( Both curves are Same (Identically Curved).Pretty Clean, tho..a few scratches on One side..(But is not affected)..For Lower Powered Research (Nebula, Galaxies, Infinity)!!
Power you use depends on what Size Optical Telescope you use..Withthis Eyepiece, powers vary from the Size of your Scope..Scope== Size& Your 'Scope'...
Filed under: Eyepieces & Accessories