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:
1. You're more likely to see a sharper, higher contrast image, because:
A. The Dioptrx is always completely aligned to the eyepiece optics, eliminating aberrations from a decentered mismatch of eyeglass power and astigmatic axis.
B. 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.
C. Dioptrx likely has better multi-coatings than eyeglasses, and certainly is better in transmission and reflection reduction than uncoated eyeglass.
D. Dioptrx is more likely to be cleaner than eyeglasses, which may have scratches and smudges from constant use and wear and tear.
E. Dioptrx allows seeing your normal maximum contrast that eyeglasses can diminish (remove your eyeglasses and see how contrast improves in normal vision).
2. You're more likely to see the full field in 100° Ethos eyepieces because your eyeglasses are more limiting in "effective eye-relief".
How to Choose DIOPTRX™ Models
Your prescription may look like this, with different numbers.
Simply choose DIOPTRX™ to match the cylinder (astigmatism) value of your preferred viewing eye. In the example above, you would choose 0.5 diopter model for your right eye and 1.5 diopter model for your left eye.
Ignore spherical and axis values. Ignore all ± signs. Pupil Size vs. Astigmatism Maximum pupil size decreases with age and this decrease the visibility of astigmatims. Consult the following charts.
Eye Pupil Size vs. Age
Exit Pupil Size vs. Astigmatism Visibility
Long Eye-Relief Tele Vue Eyepieces that accept DIOPTRX™:
William Optics EyepiecesVixen Eyepieces and Barlow LensesCelestron Eyepieces & Barlow LensesBaader Eyepieces & Barlow LensesSky-Watcher and OVL Eyepieces and Barlow LensesExplore Scientific EyepiecesMeade Eyepieces and BarlowsOrion USA Eyepieces & Barlow LensesPentax Super-Wide Angle EyepiecesAPM Eyepieces and BarlowsVernonscope Eyepieces and Barlows
Lunt and Coronado Solar EyepiecesZoom EyepiecesSpecialist EyepiecesReticle EyepiecesRonchi Eyepieces
BinoviewersEyepiece and Accessory SetsEyepiece Bags and Cases2-1¼ AdaptersEyepiece ClampsRings and ExtendersEyepiece Accessories