Pentax SMC XW40-R Eyepiece (2 Inch)

The new Pentax SMC XW40-R is a long focal length eyepiece which is ideal for Nebula and Star Cluster observations. All SMC Pentax XW series eyepieces feature an extra wide 70 degree apparent angle of view and an extra long 20mm eye relief to deliver an exciting wide perspective image. The high performance XW-series optics incorporates high refraction, extra low dispersion lanthanum glass elements to produce a well balanced image with minimal aberrations. It is particularly designed to reduce the disturbing blackout effect by effectively compensating the spherical aberration of the pupil. All lens surfaces that come in contact with air are treated with the original multi layer coating, while all laminated surfaces are treated with the innovative partial coating, to offer the light transmission efficiency of more than 90 percent (an astonishing 96 percent at 550nm) over the visible light spectrum.