Pentax XW 3.5mm 70° 1.25″ Eyepiece
The Pentax XW 3.5mm is an eyepiece built for observers who demand uncompromising optical quality. Its short focal length, combined with a 70° apparent field of view, delivers detailed views of planetary discs, double stars and the lunar surface - all with a comfortable sense of space at the eyepiece. Lanthanum low-dispersion glass ensures high resolution, strongly suppresses chromatic aberration and minimises distortion across the entire field of view.
Precision optical design
The optical system uses eight lenses in five groups, developed with the help of extensive computer modelling. The result is a design that effectively controls internal reflections, maintains image brightness and preserves contrast even at high magnification. Every optical element carries Pentax SMC multi-coatings - a reference standard in the industry.
Weatherproof and versatile
The XW series meets JIS Class 4 weatherproofing, so the eyepiece handles damp nights, mist and light rain without any difficulty. The body features an M43x0.75 thread for direct camera attachment, making it equally useful for visual observation and astrophotography. A 20 mm eye relief ensures comfortable viewing for eyeglass wearers.
A professional-grade choice
The Pentax XW 3.5mm eyepiece matches the optical quality and build standard of premium manufacturers such as Tele Vue. It is the right choice for observers who want a long-term, reliable tool for demanding night-sky work.
Key specifications
| Parameter |
Value |
| Focal length |
3.5 mm |
| Apparent field of view |
70° |
| Barrel diameter |
1.25″ |
| Optical design |
8 lenses in 5 groups |
| Glass type |
Lanthanum low-dispersion glass |
| Coatings |
Pentax SMC (fully multi-coated) |
| Eye relief |
20 mm |
| Camera thread |
M43x0.75 |
| Weatherproofing |
JIS Class 4 |
Who is this eyepiece for?
- Observers focused on planetary detail and lunar surface features
- Double star enthusiasts who need high magnification with clean contrast
- Astrophotographers who want a single eyepiece for both visual work and camera use
- Eyeglass wearers who need generous eye relief
- Anyone looking for a premium eyepiece built to last for years
Why choose the Pentax XW 3.5mm?
Very few eyepieces combine this level of optical correction, practical weatherproofing and direct camera compatibility in a single unit. The Pentax XW 3.5mm is a long-term investment in your observing setup - one that will perform night after night, whatever the conditions.
