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Explore Scientific 20mm 100° field waterproof 2" eyepiece |
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Explore Scientific 20mm 100° field waterproof 2" eyepiece
Eyepiece is nitrogen-purged and waterproof preserving the internal elements to
remain as pristine as the day they were assembled.
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 The
new 20mm Explore Scientific 100° field 2" eyepiece is O-ring sealed and
nitrogen-purged to be 100% waterproof. To insure a perfect seal,
Explore Scientific tests every eyepiece in one meter of water for 30
minutes before shipping. Internally sealing the eyepiece and purging
it with inert, dry nitrogen gas 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 20mm Explore
Scientific eyepiece, has high contrast, comfortable eye relief, and
full field sharpness – with well-controlled astigmatism, field
curvature, and lateral color. Its nine element optical system (using
lenses of dense crown, light crown, dense flint, and lanthanum rare
earth optical glasses) is designed for maximum field/medium power deep
space use with telescopes having focal ratios down as low as f/4. It is
exceptionally effective on nebulas with fast f/ratio reflectors, such as
Dobsonians, as it gives both an immense field and a bright exit pupil
(almost 4.5mm with the typical f/4.5 Dob). Its very wide field also
makes it convenient for moderate power lunar and globular cluster
observing with Dobsonians, as you have much longer to observe before the
planet drifts out of the field and the scope has to be repositioned
than you do with a 60° or 70° (or even 82°) field eyepiece. In addition
to Dobs, the new 20mm Explore Scientific Explore Scientific is marvelous
for observing open clusters, nebulas, galaxy clusters, and globular
clusters with any telescope capable of using a 2" eyepiece. The
100° apparent field of this new 20mm Explore Scientific eyepiece is
nearly 50% larger in area than an 82° field eyepiece. You could get
a similar true field with a longer focal length (but narrower apparent
field) conventional eyepiece, but the 20mm Explore Scientific Explore
Scientific has the benefits of the higher power and darker sky
backgrounds that are inherent in its shorter focal length. You can use
the field of view calculator below to see just how much sky the Explore
Scientific can reveal with your telescope. 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. With an
eye relief of 14.5mm, the 20mm Explore Scientific would normally
somewhat vignette the field of view for eyeglass wearers. However, since
the 100° field is so wide that you can’t see the full field without
having to move your head from side to side to take it all in anyway,
vignetting in the conventional sense is not a problem. The 20mm
Explore Scientific fits 2" focusers only. A safety groove is machined
into the 2" chrome barrel to engage your focuser thumbscrew. This helps
prevent the eyepiece from falling should the thumbscrew accidentally
loosen while observing. Using advanced computer design, combinations of low
dispersion and high refractive index optical glasses, and durable
multilayer deposition coatings, Explore Scientific 100° Series™
hyper-wide field eyepieces are optimized to produce high contrast, high
resolution, and superior flat field characteristics, and yes they are
indeed ruggedized and waterproof to withstand the outdoor environment.
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Most amateur astronomy is done outdoors, often with a group of
people eager to get to look through the telescope. Eyepieces are often
subjected to dew, humidity, pollens, dirt, dust, fingerprints, eye
makeup, you name it...
Waterproof eyepieces are built for the outdoor environment and
are worry-free as they keep the internal optics pristine. And cleaning
them to the very edges of the glass is a breeze! Watch us at the
Northeast Astronomy Forum as we demonstrate how to clean Explore Scientific Nitrogen Purged Waterproof Eyepieces |
The visual effect of these eyepieces with
their long eye-relief and their 100° apparent field is an extreme
full-immersion experience. You have to try it understand the visual
impact that these eyepieces produce.
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The development of the Explore Scientific 14mm 100° Series
Nitrogen-Purged Waterproof™ Eyepiece was a collaborative effort of
astronomers and engineers who tested our prototypes again and again, in
the field and in the factory to make refinements to produce the final
production eyepiece.
Here we see the first prototype being assembled in the Kunming facility.
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Inspiration for ultra-wide field eyepiece designs came from several designers. Wright H. Scidmore [1] patented
important ultra-wide angle eyepiece designs (one with long eye-relief)
in the ‘60s for the U.S. government. His influence can be seen in many
eyepiece designs on the market today with eyepieces of 68 to 80 degrees
apparent field and more. Carl Zeiss [2]
made eyepieces of 110 and 120 degrees apparent field for use in U-boat
periscopes before World War II. These are but two notable designers who
developed ultra-wide field eyepieces over the decades. |
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Like all Explore Scientific eyepieces, the lens elements of the 100°
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.
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These eyepieces with their huge
apparent field of view not only gave the observer a panoramic visual
experience, but they relax the eye so the observer could pay attention
to subtle details for extended periods. These ultra-wide angle eyepieces
played a critical role in the military for aiming at targets, and their
long eye-relief counterparts helped reduce eye injury from recoil.
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Each 100° Series Nitrogen-Purged Waterproof eyepiece is internally
sealed and purged with inert, dry nitrogen gas to prevent internal
fogging, to halt the intrusion of fine particulates and fungus, and to
maximize the life of the internal coatings. To make sure, every 100° eyepiece is tested by submerging them down to 1 meter of water for 30 minutes.
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Years later such eyepiece designs
transformed the visual experience for amateur astronomers, as they
started using military surplus cannon sight eyepieces on their backyard
telescopes. Al Nagler with his company Tele Vue introduced his Nagler 82
Degree eyepieces[3] (and later introduced the 100 degree Ethos eyepieces), and then other commercial telescope companies such as
Meade Instruments, Pentax, Celestron, and others made ultra-wide field
eyepieces specifically for use in amateur telescopes. Since extreme
performance eyepieces are expensive to make, they come with a relatively
high price tag over standard eyepieces.
After announcing Explore Scientific’s
line of telescopes at the Astronomical League Conference in the summer
of 2008, we decided to focus on extreme performance, ultra-wide angle
eyepiece designs as well. We 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.
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Each and every Explore Scientific eyepiece is inspected both at the factory and again at our facilities.
Here we are making final visual and cosmetic inspections where we check
for assembly integrity, cleanliness, and optical performance (including
a test for visual image edge consistancy) before shipping them to our
customers.
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Developing our new eyepieces we wanted
to take a fresh perspective and address several points. Our goal was to
produce an ultra-wide angle design that provides pride of ownership at a
great value:
Focus on Value - We invite direct comparison to any eyepieces on the market in their category.
Protection from the Outdoors
- By making the eyepiece body nitrogen-purged and waterproof eyepiece
internal elements will remain as pristine as the day they were
assembled. The sealed, dry environment is impervious to internal fogging
and contaminants such as fungus growing in between the lens elements.
Our waterproof eyepiece is 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 insure a perfect seal we
test every eyepiece in one meter of water for 30 minutes.
Creating an Identity
- We look at purchasing fine optical equipment as an investment, and it
should be treated as such. With a unique serial number on each
eyepiece we can track when a product was made, and the owner can
document their equipment for insurance and warranty purposes.
Providing Peace of Mind -
Explore Scientific stands behind our products with a free 5 Year
Transferrable Limited Warranty upon registration of the product. Want to
trade or sell your eyepiece? You’ll get more value if its remaining
warranty can be transferred to the new owner.
[1] Ref: W.H. Scidmore, Wide-angle eyepiece, USP 3390935 (1965), and USP 3384434 (1968)
[2]
Ref: A New Telescope Eyepiece with Extremely Large Field of View by
Horst Kohler, Oberkochen from Optik, Journal for Light and Electron
Optics Special Reprint, Optik 17 (1960), pp500-509
[3] Ref: The eyepiece that changed observing, Astronomy Magazine (Dec, 2005)
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Free Extended Warranty!
Buy an eyepiece for yourself or give it as a gift, then submit the
registration form to receive a free extended five year warranty in the
USA! |
All Explore Scientific telescopes and telescope accessories
are covered under our standard U.S.A. One Year Limited Warranty against
defects with proof of purchase, but you can extend this limited warranty
to five years by simply filling out the product registration and submitting it in within 60 days.
This program is also available to the person who receives your gift
of an Explore Scientific eyepiece. You don't need to give them the
purchase receipt, just remind them to fill out the registration, and
we'll take care of the rest.
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