An amazing hyper-wide 120° field w/Sharp images & good transmission from EMD coatings, Argon purging to preserve the seals--waterproof for years to come. 9mm FL, 2"

• 9MM FOCAL LENGTH
• 120° APPARENT FIELD
• 12 ELEMENTS
• FLIP-UP RUBBER EYECUP
• COMFORTABLE EYE RELIEF
• RUBBER GRIP RING ON BARREL
• THREADED FOR FILTERS
• WATERPROOF
• DRY ARGON PURGED (LONGER SEAL LIFE)
• FULLY MULTI-COATED W/EMD COATINGS

NOTE; NOT COMPATIBLE WITH CELESTRON LUMINOS 2" BARLOW.  LENSES MAY TOUCH UNLESS BARREL EXTENSION IS ADDED TO EYEPIECE BARREL
The world's widest apparent field eyepiece for astronomy, the new 9mm 120° Series Argon-Purged Waterproof Eyepiece, has been extensively field tested by amateur astronomers at star parties in Canada and the USA, and is now in the production stage. What we learned during these tests was that about half of the viewers could see the entire boundary of the field stop at once, while the other half could only see stars as far to the edges that their eyes would permit without seeing a boundary.

Either way we felt we had reached our goal to produce a highly corrected to the edge of the field, maximum hyper-wide eyepiece. We also found an opportunity to fine-tune the contrast performance as we started production, which has set our expected delivery to August 2012 for the first units.

The new 12-element 9mm Explore Scientific deep sky eyepiece has a hyperwide apparent field of view that’s an immense 120° across! It’s the widest field of view available in any commercial eyepiece. An astronomy first from Explore Scientific, the 120° apparent field of this new 9mm Explore Scientific shows more than twice the sky area of an 82° eyepiece and even a whopping 44% larger area than a 100° eyepiece.

The 9mm was field-tested for the first time at Starfest in Canada, August 2011, and at several other major star parties since then. Hundreds of experienced astronomers who waited in line at these star parties to get a chance to view through the hyperwide 120° Explore Scientific 9mm were stunned by the full-immersion observing experience. Even when compared with a 9mm 100° field eyepiece, the difference was “quite palpable," to quote one experienced observer. The telescope seemed to truly disappear in the 120° field, bringing them face to face with the Universe in an intimate and personal way never before possible. It’s an awe-inspiring observing experience you can repeat for yourself every night you go out with your scope.

This deep sky eyepiece, the first of its kind for astronomy, is designed specifically and exclusively for deep sky observing. During the day, lateral color is clearly visible. However, put the eyepiece in a scope at night, its natural habitat, and the lateral color completely disappears, showing only a highly corrected field of pinpoint stars across its entire 120° apparent field of view. The views of globular clusters, compact open clusters, nebulas, and galaxies are breathtaking. You can use the field of view calculator below to see just how much sky the Explore Scientific can reveal with your telescope.

This 2" Explore Scientific 120° eyepiece is O-ring sealed and argon-purged to be 100% waterproof. Internally sealing the eyepiece and purging it with inert, dry argon gas (which has lower permeability through the eyepiece's polymer seals than nitrogen) prevents internal fogging in the eyepiece when observing at sub-freezing temperatures. For observers in dusty climates, sealing keeps wind-blown dust and fine particulates from getting into the eyepiece body. For observers in very humid climates, sealing prevents the growth of fungus on the internal lens elements. For all observers, complete sealing maximizes the life of the internal optical coatings and makes the eyepiece easier to clean, as there is no risk of cleaning solution migrating from the top of the lens and seeping around edges to be trapped in between elements.

The 9mm Explore Scientific eyepiece, has high contrast and full field sharpness – with well-controlled astigmatism, field curvature, and nighttime lateral color. Its twelve element/eight group optical system (using lenses of dense crown, light crown, dense flint, and lanthanum rare earth optical glasses with 15-layer multicoatings on all air/glass surfaces) is designed for maximum field/high power deep space use with telescopes having focal ratios down to f/4 and below.

There is a soft rolldown eyecup to shield your eye from ambient light (from a neighbor’s security light, for example) and improve the image contrast. The eye relief is a comfortable 13mm.

The 9mm Explore Scientific fits 2" focusers only. A shallow tapered groove is machined into the 2" chrome barrel to engage your focuser thumbscrew or compression ring. This helps prevent the eyepiece from falling should the thumbscrew accidentally loosen while observing. The sides of the groove are slanted to avoid catching on your focuser's compression ring when removing the eyepiece from your scope.

This individually serial numbered Explore Scientific product is backed by a limited one year warranty, which will be extended to an Explore Scientific STAR lifetime transferrable limited warranty when the product warranty card is registered with Explore Scientific within 60 days of purchase.