Instadjust for Nagler Type 4 and Radian Eyepieces
Instadjust was developed for maximizing contrast while aiding proper eye position
for non spectacle wearers. It is essential because without wearing spectacles it is possible
to get too close to the eyepiece, resulting in vignetting where the edge field rays can
miss the pupil of the observer's eye.
The push-pull, click-stop adjustment permits fast positioning and maximum suppression
of environmental stray light.the pictures below shows a radian eyepiece with the instadjust
in position for spectacle wearers and for non-spectacle wearers.
Another unique development is the pupil guide. It helps those without spectacles,
especially novices, to stay centered on the exit pupil. The pupil guide is included
with all radian and nagler type 4 eyepieces and fits under the soft fold-down
rubber eyeguard.
Tele Vue have produced a new ring to replace the originals if required.
The new ring simply threads on in place of the original name-ring. You can tell the difference by noting the smooth black finish inside the older ring, since it lacks the internal friction strip of the new style.
The push-pull, click-stop adjustment permits fast positioning and maximum suppression
of environmental stray light.the pictures below shows a radian eyepiece with the instadjust
in position for spectacle wearers and for non-spectacle wearers.
Another unique development is the pupil guide. It helps those without spectacles,
especially novices, to stay centered on the exit pupil. The pupil guide is included
with all radian and nagler type 4 eyepieces and fits under the soft fold-down
rubber eyeguard.
Changing the Instadjust Tension on the Radians
- With the eyepiece standing upright on a table, unscrew the engraved name ring from the Instadjust housing.
- Hold the chrome barrel and slide the Instadjust housing up and off the eyepiece. Be careful that the spring wire within the housing doesn't fall out and hit the eyelens.
- With the housing clear of the eyepiece, remove the spring wire from its groove. A toothpick may help you extract it.
- To tighten the Instadjust tension, squeeze the diameter of the wire slightly smaller. To loosen the Instadjust tension, stretch the diameter slightly larger. Small amounts make a big difference in feel.
- Place the wire back in the groove in the Instadjust housing. It will float.
- Reinstalling the housing isn't difficult, but takes some finesse. Slide the housing over the eyepiece. Tilt the housing slightly to try to catch the two ends of the wire under the top lip of the eyepiece. Then, at 180 degrees around from the open end of the spring wire, press the wire into the groove while gently pushing the housing down. Once you get it in the top position, you should be able to slide the Instadjust down the eyepiece barrel freely.
- Thread on the name ring, which acts as the stop.
Instadjust on the Naglers
Recent Type 4 Naglers (12mm, 17mm, and 22mm), have been fitted with a new type "name-ring" with an internal friction strip to tighten and further smooth the Instadjust motion. (Some users found the original motion too loose.)Tele Vue have produced a new ring to replace the originals if required.
The new ring simply threads on in place of the original name-ring. You can tell the difference by noting the smooth black finish inside the older ring, since it lacks the internal friction strip of the new style.