About the Explore Scientific 20mm 100 Degree Series Waterproof Telescope Eyepiece - 2"...
The Explore Scientific 100 Degree Series Telescope 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 Degree 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 - like the Explore Scientific 100 Degree Series Telescope Eyepiece - 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 20mm 100 Degree Series Waterproof Telescope Eyepiece - 2" Features...
Optimized Optical Design: Explore 100 Degree 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 Degree 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 Degree 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 Degree 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 20mm 100 Degree Series Waterproof Telescope Eyepiece - 2" Specifications...
Focal Length: 20mm
Barrel Size: 2"
Field Stop Diameter: 34.8mm
Eye Relief: 14.5mm
Dimensions: L=156mm x W=70mm
Weight: 968 grams; 38.1 ozExplore Scientific Product Number: (EPWP10020-00]