Ethos 1.25" and 2" Telescope Eyepieces | Telescope.com: Tele Vue

Design

Design

Different eyepiece designs allow for a wide range of features, depending on the needs of the observer. Orthoscopic and Plossl designs can provide a great quality image with a standard field of view, but may be difficult to use at higher powers while wearing glasses due to the short eye-relief. Long eye-relief designs have more elements and can be more expensive, but work very well with glasses, even at higher powers. Wide angle designs provide a larger view of the sky at the same power as a standard eyepiece. More complex designs can combine all these attributes together in a single eyepiece.

Proprietary
Eye relief

Eye relief

The distance, measured in millimeters, between the observer's eye and the eyepiece lens in which the entire field of view remains visible. Eye relief varies with the optical design but generally increases with decreasing magnification. Long eye relief is advantageous for observers who wear glasses, as they don't have to put their eye directly on the eyepiece to see the entire field of view, nor do they have to remove their eyewear.

15.0mm
Coatings

Coatings

Lenses are coated with an antireflective material to ensure that as little light as possible is reflected away, so more gets to your eye. Good lenses are at least "fully coated," with a single layer of magnesium fluoride applied to each air-to-glass lens surface. Multiple layers of coatings are even more effective; the term "multi-coated" means one or more lens surfaces have multiple coatings. "Fully multi-coated" is even better, meaning that all lens surfaces are multiple-layer coated. Mirror star diagonals are coated with a reflective material similar to telescope mirrors in order to reflect the light into the eyepiece. Standard aluminum coatings reflect between 88%-92%, and enhanced aluminum reflects 97%. Dielectric coatings use a different process to deposit a coating that reflects 99% of the light. In addition to the higher reflectivity, Dielectric coatings are much more durable than aluminum coatings, so they last longer and can be cleaned with less risk of damage.

Fully multi-coated
Filter threads

Yes
Barrel security recess

Barrel security recess

The barrel security recess is a shallow groove or depression cut into the 1.25" or 2" barrel of the eyepiece. In the event the thumb screw holding the eyepiece in the focuser becomes slightly loose, the eyepiece will not fall out because the tip of the thumb screw will catch on the lip of the security groove.

Yes
Blackened lens edges

Blackened lens edges

Blackened lens edges in eyepieces and refractor lenses prevent unwanted light scatter inside the tube. This results in higher image contrast.

Yes
Rubber eyeguards

Yes
Body material

Aluminum
Case

No
Warranty

Limited lifetime

Design

Eye relief

Coatings

Barrel security recess

Blackened lens edges

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About Orion Telescopes & Binoculars

Design

Eye relief

Coatings

Barrel security recess

Blackened lens edges

Why Buy From Orion

Why Buy From Orion

Shop Our Catalogs

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About Orion Telescopes & Binoculars