Quillon Saltmarsh 5 mm planetary eyepiece, with hard case

Specifications

Description

The Saltmarsh 5 mm planetary eyepiece is a four-element design with a 50-degree apparent field and a 1.25 in barrel. At 5 mm it is one of the shortest focal lengths in the Quillon range, and it gives high magnification in most telescopes: 200x in a 1,000 mm refractor, 240x in a 1,200 mm Dobsonian, and 406x in a 2,032 mm Schmidt-Cassegrain. The 4.7 mm field stop sets a true field of about 13 arcminutes in a 1,200 mm telescope. That is enough to hold the full disk of Jupiter at its largest, a small planetary nebula, or a close double star with room to spare, but it is too narrow to frame the full Moon.

A planetary design at this focal length keeps its image sharp only when the telescope is slow enough to suit it. In telescopes slower than about f/8, stars stay small and round across most of the field. In faster instruments, the edge of the field shows some softening, and bright stars may show a faint color fringe. The lens surfaces are fully multi-coated to improve contrast, and the barrel interior is blackened to reduce scattered light from the telescope and from the eyepiece itself.

The 6 mm of eye relief means your eye must sit close to the top lens to see the full field, so the rubber eyeguard helps you hold a steady position. Observers who wear glasses may need to view with glasses removed to see the whole field. The 1.25 in barrel fits standard focusers, diagonals, and Barlow lenses, and it accepts 1.25 in filters. Pair it with a 10 mm or 15 mm eyepiece to cover a range of magnifications, and use a Barlow lens for higher power when seeing conditions allow.

About this configuration

All configurations of the Quillon Saltmarsh 5 mm planetary eyepiece share the same optical design; the options change the eyecup, the case, and the finish. 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 fold-down eyecup is simple and has no moving parts that can loosen in cold weather.

A color ring near the top of the body marks the focal length, which helps when you swap eyepieces in the dark. The 2023 edition uses the same lens design as later years, with small differences in the grip pattern. 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 rubber eyeguard
• Top and bottom dust caps
• Plastic storage case
• Hard foam-lined case

Compatibility notes

• Fits any 1.25 in focuser, diagonal, or Barlow lens.
• The barrel accepts standard 1.25 in filters.
• Sharp across most of the field at f/8 and slower; softer at the edge in faster telescopes.