Sky-Watcher Plossl SWA 6mm 58° 1.25″ eyepiece
Looking for an eyepiece that significantly boosts the performance of your telescope without coming at an astronomical price? The Sky-Watcher SWA-58 Plossl 6mm is exactly that choice - it offers a 58° apparent field of view, fully multi-coated FMC optics and a comfortable 16mm eye relief. Whether you want to explore the details of the lunar surface, observe Jupiter's cloud bands or split close double stars, this eyepiece delivers a precise, high-contrast image with minimal ghosting and flare.
Optical design
The SWA-58 series builds on the classic Plossl design but adds a fifth optical element arranged in three groups, which widens the field of view without sacrificing sharpness at its edges. All 5 lenses feature full multi-layer FMC anti-reflection coatings, maximising light transmission and effectively suppressing unwanted ghosts and reflections. The result is a bright, contrastive image with high colour fidelity across the entire field - a quality particularly appreciated by planetary and lunar observers. The 6.1mm field stop diameter matches the 6mm focal length and ensures a sufficiently bright beam even when used with medium-speed telescopes.
Comfort and compatibility
The retractable rubber eyecup allows you to adjust the eye distance so that the full field of view is used without distracting shadows - including observation through glasses, because the 16mm eye relief is exceptionally generous for the 6mm focal length class. The 58° wide-angle field of view gives observation a pleasant sense of space and significantly simplifies centring and tracking moving objects. The standard 1.25″ filter thread allows instant attachment of lunar, planetary or broadband filters without any adapters.
Recommended applications
With its 6mm focal length, this eyepiece is designed primarily for high magnifications. It is ideal for:
- Detailed study of the lunar surface
- Observation of planetary disks - Jupiter, Saturn and Mars at opposition
- Splitting close double stars
- Compact planetary nebulae and globular clusters in fast telescopes (f/5 and shorter)
The eyepiece works reliably in any telescope with a 1.25″ focuser, including binocular viewers - where its low price and optical quality are appreciated by anyone building a matched pair.
Available focal lengths in the SWA-58 series
The eyepiece is available in a wide range of focal lengths, making it possible to assemble a complete set for any telescope:
- 2.5 mm
- 3.2 mm
- 4 mm
- 5 mm
- 6 mm
- 7 mm
- 8 mm
- 9 mm
- 15 mm
- 20 mm
- 25 mm
Technical specifications
| Parameter |
Value |
| Focal length |
6 mm |
| Apparent field of view |
58° |
| Eye relief |
16 mm |
| Field stop diameter |
6.1 mm |
| Barrel diameter |
1.25″ |
| Optical elements |
5 lenses in 3 groups |
| Coatings |
FMC (fully multi-coated) |
| Filter thread |
Standard 1.25″ |
| Eyecup |
Retractable rubber |
Summary
The Sky-Watcher SWA-58 Plossl 6mm appeals to beginner astronomers looking for a quality upgrade over the eyepiece supplied with their telescope, as well as experienced amateurs who want to expand their kit without unnecessary expense. The combination of a solid optical construction with FMC coatings, comfortable 16mm eye relief and a standard filter thread makes it a versatile companion for planetary observation, double stars and compact deep-sky objects. The SWA-58 series from Sky-Watcher has earned a solid reputation over the years thanks to consistent quality and an excellent price-to-performance ratio - and this 6mm model is no exception.
