Quillon Halyard 5 mm wide-field eyepiece

Specifications

Description

The Halyard 5 mm is a five-element wide-field eyepiece with a 60-degree apparent field and a 1.25 in barrel. At this focal length it works as a high-power eyepiece for close double stars, planetary detail, and the dense cores of globular clusters. In a 1,200 mm telescope it gives 240x with a true field of about 0.24 degrees, and in a 2,032 mm Schmidt-Cassegrain it gives 406x with a true field of about 0.14 degrees. Start at lower power and centre the target before you switch to this eyepiece.

The 5.0 mm field stop sets the true field in every telescope. Because the apparent field is 60 degrees, the eyepiece keeps the image wide at high power, so you can hold a target near the centre of the view for longer. The five elements are fully multi-coated to reduce internal reflections in the high-power beam. Edge sharpness depends on the telescope, and faster reflectors will show more softening toward the edge than slower refractors.

The eye relief of 10 mm is short for an eyepiece of this design. Observers who wear glasses may need to remove them to see the full field, and the rubber eyecup gives limited support against the brow. The barrel is threaded for standard 1.25 in filters. Combined with a Barlow lens, this eyepiece reaches high magnifications, so check image steadiness before using the combination. At 95 g, the eyepiece balances well on a focuser and a diagonal of moderate weight.

About this configuration

The Quillon Halyard 5 mm wide-field eyepiece is offered in several configurations, and the notes below describe what this particular one adds. 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. The twist-up eyecup sets your eye at the right distance from the lens, with or without glasses.

The silver anodized body is easy to find in a dark accessory case and wipes clean after dewy nights. The 2023 edition uses the same lens design as later years, with small differences in the grip pattern. 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 rubber eyecup
• Top and bottom dust caps
• Padded storage pouch

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).
• Eye relief of 10 mm suits observers without glasses; glasses wearers may need to remove them.