Explore Scientific 120° 9mm Waterproof Eyepiece

Explore Scientific 120° 9mm Waterproof Eyepiece


Out of stock

Explore Scientific 9mm 120° Series Argon-Purged Waterproof Eyepiece; EMD Coatings; 2″; 12.5mm of eye relief; Weighs 21.2 ozs./ 1.3 lbs.

Out of stock



Pushing the boundaries of eyepiece design, Explore Scientific spent years developing the 120-degree eyepiece, adding to it the bonus of an Argon purged interior space ensuring that your investment is immune to the outside environment and your eyepiece never falls victim to a damp night.

Like all Explore Scientific eyepieces, the lens elements of the 120-degree eyepiece are meticulously cleaned and aligned before being installed in their precision machined lens barrels.

Each lens and lens grouping have EMD (Enhanced Multilayer Deposition) Coatings and are edge-blackened to eliminate light scatter and maintain image contrast.

Contrast is further enhanced with baffles that mask and deflect unwanted stray light.

These eyepieces with their enormous apparent field of view give the ultimate panoramic experience and with such a wide field, your eye can truly relax and bring in even the faintest details.

Each 120-degree Series Argon-Purged Waterproof eyepiece is internally sealed and purged with inert, dry Argon gas to prevent internal fogging, to halt the intrusion of fine particulates and fungus, and to maximize the life of the internal coatings. Waterproof eyepieces are easier to clean, and there is no risk of cleaning solution migrating from the top of the lens and seeping around edges to be trapped in between elements.

To make sure, every 120-degree eyepiece is tested by submerging them down to 1 meter of water for 30 minutes. After announcing Explore Scientific’s line of telescopes at the Astronomical League Conference in the summer of 2008, they decided to focus on extreme performance, ultra-wide angle eyepiece designs as well. Explore wanted to offer ultra-wide angle designs in popular formats at lower prices. Now more astronomers could experience the benefits of the amazing panoramic views these eyepieces provide.

Each and every Explore Scientific eyepiece is inspected both at the factory and again at their USA facility in California to ensure the highest degree of quality. Final visual and cosmetic inspections where the assembly integrity, cleanliness, and optical performance (including a test for visual image edge consistency) before shipping them to OSI.

The Explore Scientific 9mm 120° Series™ eyepiece really is in a class by itself. The 120° apparent field of view is unlike anything you have experienced before. Normally, when we look through hyper wide field eyepieces, we see a huge swath of the night sky at low magnification. With the 9mm 120°, however, you see even more universal real estate, but you also see the main attraction, whether it is a nebulae, a galaxy, or a star cluster, close up and personal. In our opinion, it is the best of both worlds.

With such a wide field, you will also notice that objects stay in the field of view for a long time. This is especially noticeable when your telescope does not have a drive, like a Dobsonian or a refractor on a grab and go mount like the Explore Scientific Twilight I. Another great benefit of hyper-wide eyepieces is the ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.


There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

  • Explore Scientific 9 mm 120 Degree Eyepiece
Description9mm 120° Series Argon-Purged Waterproof Eyepiece
Item NumberEPWP12009-01
Focal Length9mm
Weight21.2oz; 602g
Barrel Size2.00”
Eye Relief12.5mm
Field Stop Diameter:15.7mm