Lenses are coated with an anti-reflective material to ensure that as little light as possible is reflected away, thus more gets to your eye. Good lenses are at least "fully coated," with a single layer of magnesium fluoride applied to each air-to-glass lens surface. Multiple layers of coatings are even more effective; the term "multi-coated" means one or more lens surfaces have multiple coatings. "Fully multi-coated" is superior because all lens surfaces are multiple-layer coated. Mirror star diagonals are coated with a reflective material similar to telescope mirrors in order to reflect the light into the eyepiece. Standard aluminum coatings reflect between 88%-92%, and enhanced aluminum reflects 97%. Dielectric coatings use a different process to deposit a coating that reflects 99% of the light. In addition to the higher reflectivity, Dielectric coatings are much more durable than aluminum coatings, so they last longer and can be cleaned with less risk of damage.

"Diffraction Limited" means that the limits of image detail are determined by the physical properties of light, and not by optical defects in the telescope.

Instead of a single thumb screw locking the eyepiece in place, a brass ring compressed by a thumb screw secures the eyepiece. This spreads clamping force over a larger area of the eyepiece's barrel, which provides a better connection. The compression ring also prevents the tip of the thumb screw from producing unsightly scratches and divots on the eyepiece barrel.