Halden Lowmoor 12 mm wide-field eyepiece, with hard case

Specifications

Description

The Lowmoor 12 mm is a five-element wide-field eyepiece with a 50-degree apparent field and a 1.25 in barrel. Its focal length falls in the 10 to 16 mm range, which places it between low-power and medium-power eyepieces. It suits a broad set of telescopes for general observing, from open clusters to large nebulae.

In an 800 mm refractor, a 12 mm eyepiece gives 67x. In a 1,200 mm Dobsonian it gives 100x, and in a 2,032 mm Schmidt-Cassegrain it gives 169x. In the 1,200 mm telescope, the 10 mm field stop sets a true field of about 0.48 degrees. That is enough to frame the core of a globular cluster with room around its edges, or the bright central region of a planetary nebula at a moderate scale.

The design uses five elements with fully multi-coated surfaces and blackened edges to reduce internal reflections. In telescopes slower than about f/6, stars remain sharp across the central two-thirds of the field. In faster systems you may notice some softening toward the edge, so judge the outer field in your own telescope before relying on it for wide mosaics. Its wide field and moderate magnification also make it useful for finding objects before you switch to a higher-power eyepiece.

The 15 mm of eye relief suits most observers, including those who wear glasses. The rubber eyecup folds down for eyeglass wearers and folds up to block stray light. The barrel is threaded for standard 1.25 in filters. At 150 grams, the eyepiece balances well on lightweight focusers. Keep the dust caps in place when it is not in use to protect the lens surfaces.

About this configuration

The Halden Lowmoor 12 mm wide-field eyepiece is offered in several configurations, and the notes below describe what this particular one adds. The hard foam-lined case protects the eyepiece from knocks during travel and stacks neatly with other cases. A hard case keeps the eyepiece safe in a busy accessory box at a star party or an outreach event. A winged eyeguard helps you hold your eye at the right position, which makes the edge of the field easier to see.

The silver anodized body is easy to find in a dark accessory case and wipes clean after dewy nights. The optics in the 2024 edition match the other years; the changes concern the housing only. The true field in your telescope is roughly the apparent field divided by the magnification you reach with this eyepiece.

What's in the box

• Eyepiece with fold-down rubber eyecup
• Top and bottom dust caps
• Padded storage pouch
• Hard foam-lined case
• Winged rubber eyeguard

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 the central field at f/6 and slower; softer at the edge in faster telescopes.