Orion Edge-On Planetary Eyepiece Expansion Set

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
Barrel size:

1.25"
Apparent field of view:

Apparent field of view

The edge-to-edge angular diameter of the image displayed in a binocular as seen by the eyes of the observer. It is an inherent specification for a given binocular design. The "angular diameter" of an object is defined as the angle an object makes (subtends) as seen by an observer.

55.0°
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.

20.0mm
Coatings:

Coatings

Binocular lenses and prisms are often coated with anti-reflective material to minimize light loss as light travels through the multiple optical surfaces of a typical binocular. Coatings help maximize the amount of light transmitted through each glass surface of a binocular, so as much light as possible reaches the observer's eyes to provide a bright and sharp image.
Good lenses are at least "fully coated," with a single layer of magnesium fluoride coating applied to each air-to-glass lens surface. Multiple layers of coatings are even more effective; the term "multi-coated" means one or more air-to-glass lens surface has multiple coatings. "Fully multi-coated" optics are even better, meaning all lens surfaces have multiple layers of anti-reflective coatings applied for maximum light transmission and optimal image quality.

Fully multi-coated
Number of elements:

7
Filter threads:

Yes
Parfocal:

Parfocal

Parfocal refers to an attribute of an eyepiece set where little to no focusing is required when swapping out one eyepiece for another.

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.

No
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
Additional included accessories:
Other features:
Warranty:

Warranty

This warranty gives you specific legal rights. It is not intended to remove or restrict your other legal rights under applicable local consumer law; your state or national statutory consumer rights governing the sale of consumer goods remain fully applicable.

One year

Design

Apparent field of view

Eye relief

Coatings

Parfocal

Barrel security recess

Blackened lens edges

Warranty