Tele Vue Dioptrx (Specify Strength)

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).

At Texas Star Party and RTMC Astronomy Expo in May and Cherry Springs Star Party in June (all 2005), I had the pleasure of evaluating over 100 subjects using our DIOPTRX™ astigmatism correctors to evaluate both the absolute performance and performance relative to their eyeglasses. I used a Tele Vue 60 with 60° diagonal and 32mm Plössl (5.3mm exit pupil) to view our DIOPTRX™ test chart. In a few cases, I was able to confirm the performance at night using a 35mm Panoptic and 12mm Nagler Type-4 on our TV NP-127 to view star clusters. Most subjects did not have their eyeglass prescriptions or know their eyesight astigmatism, but I have enough experience now to guess at a reasonable starting point in trying DIOPTRX™. Since we had 10 models in ¼ diopter steps of astigmatism from ¼ diopter to 2½ diopters, it was easy for subjects to find their optimum values.

Following are some general conclusions:

1. DIOPTRX™ always works at least  as good as eyeglasses and mostly better.

2. People who dislike using glasses and have astigmatism are most pleased.

3. Some people are lucky enough to have no astigmatism and will not benefit from DIOPTRX™.

4. I found many people using progressive eyeglasses, which by definition are horrendous for observing with telescopes or binoculars.

5. Many people do not realize that they don't need their eyeglasses if they are near or farsighted and don't have astigmatism.

6. Critical observers easily detect as little as ¼ diopter of astigmatism.

7. DIOPTRX™ units can be stacked (one person had 5 diopters) to accommodate more than 2½ diopters astigmatism.

8. It is easy (and analogous to focusing) to "dial in" rotation of DIOPTRX™ for optimum correction. It is virtually intuitive.

9. DIOPTRX™ units are very effective in binoviewers.

10. Night tests seem to confirm no discrepancies with our daytime tests.

11. Sharper stars and detection of fainter stars are clear benefits.

12. Choosing DIOPTRX™ values based on eyeglass prescription is generally effective.

 I was very gratified by the instant and positive unprompted reactions.

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.

Maximum pupil size decreases with age and this decrease the visibility of astigmatism. Consult the following charts.

Eye Pupil Size vs. Age

Exit Pupil Size vs. Astigmatism Visibility