Brightwell Classic 25 mm Plössl eyepiece

Specifications

Description

The Classic 25 mm is a four-element Plössl eyepiece with a 52-degree apparent field and a 1.25 in barrel. It is the kind of low-power eyepiece that many telescopes ship with, and it remains one of the most useful eyepieces in any collection.

A 25 mm eyepiece gives low magnification in most telescopes: 28x in a 700 mm refractor, 48x in a 1,200 mm Dobsonian, and 81x in a 2,032 mm Schmidt-Cassegrain. Low power means a wide true field and a bright image, which makes it the eyepiece to start with when you search for a target.

The Plössl design uses two pairs of cemented lenses facing each other. It gives sharp stars across most of the field in telescopes slower than about f/6, with some softening at the edge in faster Newtonians. The lenses are fully multi-coated, and the edges are blackened to reduce internal reflections.

With 17 mm of eye relief, the Classic 25 mm is comfortable for most observers, including many who wear glasses. The fold-down rubber eyecup blocks stray light when folded up and gives room for glasses when folded down. The barrel is threaded for standard 1.25 in filters.

The field stop of 22 mm sets the true field. In a 1,200 mm telescope, that gives a true field of about 1.05 degrees, enough to frame the full Moon with space around it or to fit the whole of M31's bright core.

Because it is simple and light, the Classic 25 mm also works well in a binocular viewer or as a finder eyepiece. It is a good companion to a 10 mm eyepiece and a Barlow lens for a first set of three magnifications.

About this configuration

All configurations of the Brightwell Classic 25 mm Plössl eyepiece share the same optical design; the options change the eyecup, the case, and the finish. This configuration comes without a case, which suits observers who keep their eyepieces in a shared foam box. No case is included, so the eyepiece ships in a simple box with its two dust caps fitted. With a twist-up eyecup, you can raise or lower the cup in steps to match your eye relief needs.

The titanium gray finish has a hard anodized layer that resists wear from repeated insertion into focusers. The optics in the 2024 edition match the other years; the changes concern the housing only. To find the magnification, divide the focal length of your telescope by the eyepiece focal length in the specifications.

What's in the box

• Eyepiece with fold-down rubber eyecup
• Top and bottom dust caps
• Plastic storage case

Compatibility notes

• Fits any 1.25 in focuser, diagonal, or Barlow lens.
• The barrel accepts standard 1.25 in filters (M28.5 x 0.6 thread).
• Sharp across most of the field at f/6 and slower; softer at the edge in faster Newtonians.