3D Astronomy 1.25" L-O-A 3D Eyepiece Set for Binoviewers (Set of 2) - 21mm

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Our Product ID: E-3D-LOA3D21
Manufacturer SKU: E-3D-LOA3D21
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3D Astronomy 1.25" L-O-A 3D Eyepiece Set for Binoviewers (Set of 2) - 21mm

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Quick Overview

  • Each 1.25” eyepiece has a 21 mm focal length, 65-degree apparent field of view, and generous 18 mm of eye relief for comfortable observing during long sessions
  • Patent-pending design gives astonishing 3D views of nebulae, star clusters, galaxies, and double stars
  • Must be used with astronomical binoviewers (not included) or with binoculars that accommodate interchangeable eyepieces
  • Works best in dark skies (magnitude 5 or darker) with well-aligned telescope and binoviewer optics
  • Works with telescopes of virtually any aperture or focal ratio
  • Array eyepiece is easily adjustable to give a variable 3D perspective

Product Details


Groundbreaking eyepiece set and optical array creates an astonishing “3D” view of nebulae, galaxies, star clusters, and double stars with virtually any telescope equipped with binoviewers


The 3D Astronomy 21 mm L-O-A Eyepiece Set from 3D Astronomy is the result of a remarkable optical innovation that gives you an entirely new and dramatic visual observing experience. When used in a telescope equipped with binoviewers, or with astronomical binoculars that accommodate interchangeable eyepieces, the L-O-A Eyepiece Set renders an astonishing 3D view of nebulae, star clusters, galaxies, and double stars unlike anything available with standard eyepieces. After using the L-O-A eyepiece set, observers with decades of experience have remarked, “It’s like looking through a telescope for the first time,” and “I feel like a little kid again.”

Patent-Pending Optical Array Creates Dramatic 3D Effect

Each of the two eyepieces in this set has a focal length of 21 mm and an apparent field of view of 65 degrees. One is a standard high-quality astronomical eyepiece. The other has mounted on its field lens a tiny array of five glass mirrors. This is the “Lederman Optical Array” or L-O-A (patent pending). When used together in binoviewers, the two eyepieces create an apparent parallax between the images. This gives the perception of six layers of depth within the field of view, somewhat like the effect seen with 3D movie glasses. This renders for deep-sky objects a dramatic 3D appearance with high contrast and sharp detail. Dark lanes and bright knots in nebulae and galaxies appear more prominent. Open stars clusters appear to have depth and texture, and globular stars clusters appear as shimmering spheres of countless stars hovering in the field of view. While the 3D perspective is simulated and bears no relation to the actual physical distances between objects in the field of view, the visual effect is real, dramatic, and truly remarkable.

Variable 3D Perspective Adds Fun to Visual Observing

What’s more, you can adjust the 3D effect by rotating the array eyepiece in the binoviewer. The barrel is marked with an ‘N’ and an ‘F’. When the ‘N’ is facing towards you, an object in the center of the field of view appears nearer to you and in front of the background stars. When the eyepiece is rotated to ‘F’, an object appears farther away and behind the star field. You can turn the eyepiece continually between the two positions to vary the effect and achieve the best view.

As you adjust the array eyepiece, you’ll find yourself immersed in a breathtaking visual experience as you explore the range of perspectives available. You can also experiment with positioning an object at the center of the field of view, slightly off center, or near the edge to see how the continuous change in the 3D effect enhances the view. When they nearly fill the field, extended objects such as the Orion or Lagoon Nebulae can even appear tilted, with one edge apparently closer to you than the other, as if you were approaching the nebulae at an angle in a space ship.

Works With Virtually Any Telescope and Binoviewer

A generous eye relief of 18 mm in each eyepiece makes it easy to observe for long periods without vignetting or the kidney-bean effect. The eyepieces also have foldable eyeguards to keep out stray light. Each eyepiece is made from black anodized aluminum with a knurled ring to make for easy and secure handling. The ‘N’ on the array eyepiece is also conveniently raised so you can feel it in the dark as you adjust and explore the 3D effect.

The 3D Astronomy 1.25" L-O-A 3D Eyepiece Set produces the 3D effect with virtually any set of astronomical binoviewers (not included), and works with telescopes of any aperture and focal ratio, from small refractors to giant Dobsonians. The set also works in binoculars that can accommodate interchangeable 1.25" eyepieces including giant astronomical binoculars from Lunt and Oberwerk.

An Amazing View of Deep-Sky Objects in Dark Sky

Because a bright sky itself can come under the influence of the 3D effect, you get the best performance from the L-O-A 3D eyepiece set when observing under a dark sky in which you can see stars of magnitude 5 or fainter with your unaided eyes. You also need to keep your telescope optics and your binoviewer reasonably well aligned to get the full effect. The 3D Astronomy 1.25" L-O-A 3D Eyepiece Set works with deep-sky objects such as planetary and emission nebulae, open star clusters, globular star clusters, galaxies, and even double stars. The 3D effect does not work with the Moon, planets, or the Sun. However, you can purchase an optional third 21 mm non-L-O-A eyepiece (without the L-O-A mirror array) to match the other non-L-O-A eyepiece to view these objects.

Eyepiece Series L-O-A 3D Eyepiece
Focal Length 21mm
Barrel Size 1.25" (31.7mm)
Apparent Field of View (Mfg Specified) 65°
Eye Relief (Designed) 18mm
Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6)
Coatings Fully Multi-Coated
Lens Elements 5
Lens Groups 3
Blackened Lens Edges Yes
Barrel Type Smooth sided
Protective Plastic Storage Container Yes - Manufacturer Supplied
Protective Plastic Storage Container Size Replacement: Agena 42x60mm
End Caps 2
Rubber Eye Guard Yes
Warranty 1 year for eyepiece and array
Weight 3.6 oz each
Country of Manufacture USA