Explore Scientific 82° 14mm Waterproof Eyepiece - 1.25"

An 82° Immersive View at 14mm Focal Length

The defining feature of this eyepiece is its 82° apparent field of view. The 82° field naturally promotes relaxation at the eyepiece, so it is easier to observe for longer and details begin to materialize that may not be apparent at first glance.

This immersive effect is more than just an aesthetic improvement; it's a practical tool for observation. Explore Scientific adds that a wide field makes it easy to use averted vision, looking slightly to the side of a faint object so its light falls on a more sensitive part of your eye.

15.6mm Eye Relief for Viewing Comfort

Comfort is critical for serious observing, and the Explore Scientific 14mm eyepiece provides a generous 15.6mm of eye relief. This is the distance your eye must be from the top lens to see the entire 82° field of view. Whether you can see the whole field with glasses on depends on your glasses and eye position.

The 82° Series combines a super-wide apparent field with generous eye relief.

A 7-Element Design with EMD Coatings

The 14mm uses 7 lens elements in 4 groups. Advanced computer design and combinations of low dispersion and high refractive index glasses optimize the 82° Series for high contrast, high resolution and superior flat field characteristics.

It has durable EMD coatings and fully multi-coated optics.

• Flat Black Interior: All internal surfaces of the barrel are flat black to keep internal reflections to a minimum.
• Reduced Scatter: The lens edges are blackened to minimize scattering within the lenses.

Argon-Purged for All-Weather Reliability

Each 82° Series eyepiece is O-ring sealed and purged with an inert gas (argon) to create a waterproof environment.

Sealing keeps moisture out of the interior, so the internal surfaces do not fog; dew can still form on the outer lens.

The Standard 1.25-Inch Barrel and Physical Build

The Explore Scientific 82° 14mm eyepiece features a standard 1.25-inch barrel, for 1.25-inch focusers and diagonals. Explore Scientific assembles each eyepiece into precision machined metal lens barrels that maintain the alignment of the optical train for years of rugged use in the field. The body is 83mm long and 48mm wide.

• Lightweight Design: It weighs 256 g.

The 18.9mm Field Stop and True Field of View

The field stop is the physical aperture inside the eyepiece that defines the edge of the field of view. In the 14mm 82° eyepiece, the field stop is 18.9mm across. The size of the field stop, combined with your telescope's focal length, determines the true field of view (TFOV), the actual patch of sky you see.

You can calculate the TFOV in degrees using this formula: (Field Stop Diameter / Telescope Focal Length) * 57.3. For example, in a telescope with a 1200mm focal length, this eyepiece would yield a TFOV of (18.9mm / 1200mm) * 57.3 ≈ 0.9 degrees. That frames the Dumbbell Nebula (M27) or the Hercules Cluster (M13) with room around them.

Calculating Power with the 14mm Eyepiece

The 14mm focal length of this eyepiece provides medium-to-high magnification, making it a versatile workhorse for a wide range of celestial targets. To find the magnification it will produce with your telescope, simply divide your telescope's focal length by the eyepiece's focal length (14mm).

• With a short focal length refractor (e.g., 600mm): Magnification = 600mm / 14mm ≈ 43x. A wide view for open clusters.
• With a mid-sized Dobsonian (e.g., 1200mm): Magnification = 1200mm / 14mm ≈ 86x. A general-purpose deep-sky power.
• With a 2000mm telescope: Magnification = 2000mm / 14mm ≈ 143x, for globular clusters, planetary nebulae and the planets.

Ideal Targets for Medium-High Magnification

This power class suits globular clusters, planetary nebulae, the bright cloud structure near comet nuclei and initial observations of planets:

• Globular Star Clusters: At magnifications over 100x, bright globulars such as the Hercules Cluster (M13) and M5 begin to resolve in a medium or large telescope.
• Planetary Nebulae: The Ring Nebula (M57) shows its ring shape and the Dumbbell Nebula (M27) its two lobes.
• Bright Galaxies: Smaller galaxies such as the Whirlpool Galaxy (M51) and Bode's Galaxy (M81) fit with room around them.
• The Moon and Planets: Jupiter's cloud bands and Galilean moons, the rings of Saturn, and the larger craters and mountain ranges on the Moon.

Extending Magnification with Explore Scientific Focal Extenders

You can increase the versatility of the 14mm eyepiece by pairing it with an Explore Scientific Focal Extender. These Focal Extenders give 2X, 3X or 5X magnification increases while maintaining the eyepiece's native apparent field and eye relief.

The 1.25" models are the FE02-125, FE03-125 and FE05-125. Adding one to your collection effectively multiplies the number of magnifications at your disposal:

• With a 2x Focal Extender: The 14mm eyepiece performs like a 7mm eyepiece, doubling the magnification for planetary viewing or splitting tight double stars.
• With a 3x Focal Extender: It performs like a 4.7mm eyepiece, providing very high power for nights of excellent seeing.