Explore Scientific 5.5mm 100º Eyepiece - 2"

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Explore Scientific 5.5mm 100º Eyepiece - 2"
Item # ES-EPWP10055-01
  • The Explore Scientific 5.5mm is the newest addition to the popular line of 100º waterproof eyepieces.

  • The 5.5mm eyepiece has a 2" barrel and comes with a folding eyecup for comfort and the minimizing of stray light reflections.

  • Nitrogen purging creates a waterproof design that keeps dew from seeping into the elements...and cleaning is easy!



Go Hyper-Wide & Experience the Vastness of Space Like Never Before

The Explore Scientific 100° Series™ eyepieces are hyper-wide class oculars that can transform your visual astronomy experience. You may be startled at the amazingly wide expanse of inky black sky you behold the first time you bring your eye to a 100° Series eyepiece, and after awhile, you may even forget that you have an eyepiece between you and the universe! With an apparent field of view that is close to the maximum for hyper-wide eyepiece design, objects are not only easier to locate, but for non-driven telescopes the object will stay in the field of view for a very long time before any adjustments need to be made.

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.

Explore Scientific 100° Eyepiece Highlights

Optimized Optical Design  Explore 100° Series hyper-wide eyepieces are optimized through each design, fabrication, and testing process to produce flat-field images that have high contrast and resolution.

Exotic Glass Combinations for Optimum Results  Eyepieces are constructed of 8 or 9 lens elements (depending on the focal length) that are fabricated from combinations of Dense Crown, Light Crown, Dense Flint, and Lanthanum optical glass.

Durable Coatings & Finishing Touches  Each element in your Explore Scientific 100° eyepiece is fully multi-coated, resulting in bright, sharp images, and every element has blackened edges to reduce internal reflections and increase contrast.

Waterproof, Fog-Proof Housing The internal optics of all 100° Series eyepieces are housed in a gas-purged, waterproof barrel that keeps them as pristine as the day they were manufactured. Cleaning is much easier, and there is no need to worry about water or fluid becoming trapped in between elements due to rain, spills, heavy dew, or getting over-enthusiastic with lens cleaning fluid.

Hyper-Wide Field Experience  The 100° experience is different than that of more conventional eyepieces. A hyper-wide field of view means you can see more of the night sky at once, allowing you to observe larger or closer objects in their entirety, or to easily use inverted vision to capture faint photons of light. Also, those using Dobsonians or other instruments without a motor drive will enjoy watching an object drift more slowly across the field of view. Manually moving your telescope to compensate for the rotation of the Earth will be required much less frequently, and that's a good thing. 

Tapered 2" Barrel for Extra Security  The insert barrel of each eyepiece is double-tapered to allow smooth insertion to, and removal from, a telescope's eyepiece holder or diagonal, however the wide dimension of the taper helps prevent the eyepiece from falling out of the telescope should the set-screw holding it in place become loose. The 2" barrel is threaded to accept standard screw-on filters.

Optional Focal Extenders for Extra Magnification Explore Scientific makes a wide variety of eyepiece focal lengths, allowing a change in magnification for just about any observational study you can think of. However, if you would like to get "double duty" out of the eyepieces in your accessory case, while still retaining the eye relief of that eyepiece, use Explore Scientific Focal Extenders.

Explore Scientific 5.5mm 100º Eyepiece Specifications

  • Focal Length:  5.5mm
  • Barrel Sixze:  2"
  • Apparent Field of View:  100º
  • Eye Relief:  12.5mm
  • Waterproof:  Yes, Nitrogen-Purged
Additional Information

Additional Information

SKU ES-EPWP10055-01
UPC Code 812257014934
Manufacturer Explore Scientific
Optical Design Wide Angle
Barrel Size 2"
Warranty Lifetime Warranty
Eyepiece Field of View - Apparent 100º
Eyepiece Focal Length 5.5mm
Eyepiece Eye Relief 12.5mm
Eyepiece Manufacturer Series Explore Scientific 100º Waterproof
Special Feature Waterproof
Comes with Dust Caps? Yes
Comes with Eye Guard? Yes

Customer Reviews 1 item(s)

Initial Impression Very Good !
Haven't had a chance to use this new 5.5 mm Explore 100 deg eyepiece under ideal
condtions yet, but first impressions are very good. First light was under average seeing, and moonlit sky. Scope was a 12.5" Obsession Dob, 1600mm focal length, f/5, (approx 292x) with a variety of targets including several doubles and the Trapezium in M42. E & F stars in Trapezium were clearly visible, etc. In comparison to an Ethos 13mm (approx 138x with Paracorr), which serves as my reference eyepiece with this scope, the 5.5 Explore held its own very respectably considering the seeing conditions and higher power. Didn't notice any objectionable chromatic aberration, kidney beaning, flare, or other issues. I was concerned about edge sharpness, and I was pleased that stars were reasonably sharp to the edge of the field (no paracorr used with this focal length). No noticeable coma. Eye relief was not an issue for me (I don't wear glasses though). Considering the price (value for money), the convenience of having a high power eyepiece with a 2" barrel, and the impressive performance (at least during my first light experience), I think it merits a 4.5-5 star rating. Review by Santa_Fe_Ranger / (Posted on 3/12/2014)
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