Your telescope's focuser is used to compensate for your near- or far-sightedness; DIOPTRX compensates for your astigmatism. These units attach and lock onto the tops of over 20 long eye-relief Tele Vue eyepieces to achieve the sharpest full-field viewing possible.
DIOPTRX models are available in ¼ to 3½ diopter (¼ steps from ¼ to 2½ diopters, then ½ diopter steps to 3½-diopters), and are rotatable for tuning to the best orientation. A series of engraved letters on the barrel helps to monitor orientation. Simply choose the DIOPTRX model that matches your eyeglass prescription for astigmatism. All lenses are multi-coated glass in anodized aluminum housings with rubber eyeguards.
Benefits of using Dioptrx over eyeglasses
- You're more likely to see a sharper, higher contrast image, because:
- The Dioptrx is always completely aligned to the eyepiece optics, eliminating aberrations from a decentered mismatch of eyeglass power and astigmatic axis.
- Dioptrx can be rotated to exactly compensate for the astigmatic axis angle in real time, since both head angle and age can vary your eyesight astigmatic angle.
- Dioptrx likely has better multi-coatings than eyeglasses, and certainly is better in transmission and reflection reduction than uncoated eyeglass.
- Dioptrx is more likely to be cleaner than eyeglasses, which may have scratches and smudges from constant use and wear and tear.
- Dioptrx allows seeing your normal maximum contrast that eyeglasses can diminish (remove your eyeglasses and see how contrast improves in normal vision).
- You're more likely to see the full field in 100° Ethos eyepieces because your eyeglasses are more limiting in "effective eye-relief".