The altair lightwave 6mm planetary long eye relief eyepiece delivers high power with a short focal length telescope such as a small refractor so its ideal for high power planetary or lunar observing the 7 element 4 group computer optimised design a very smooth polish and fully multi coated optics deliver exceptional contrast and clarity the 55 apparent field of view is flat and well corrected 20mm of long eye relief means you can position your eye 20mm from the eyepiece rear lens mak