Sky-Watcher WA-66 9mm 66° 1.25″ wide angle eyepiece
Looking for an affordable eyepiece that gives you a truly wide view of the sky without sacrificing image quality? The Sky-Watcher WA-66 9mm is exactly that. It combines a proven 5-element optical design with a comfortable eye relief and a 66° apparent field of view - making it a great companion for both beginners taking their first steps in astronomy and regular visual observers.
Optics and build quality
The Sky-Watcher WA-66 wide angle eyepiece is built around a 5-element optical system with multi-layer anti-reflection coatings on all surfaces. This ensures high light transmission and minimises unwanted reflections and ghosting that would otherwise reduce image contrast. The entire eyepiece body is made of metal, and the lenses are made of glass - no plastic compromises here.
The lower part of the barrel has a standard filter thread for 1.25″ filters, so you can easily add a lunar filter, UHC filter or similar accessory without any additional adapters. The adjustable fold-down eyecup allows comfortable viewing both with and without glasses.
Field of view and image correction
The 66° apparent field of view places this eyepiece in the category of truly wide angle optics. Compared to classic Plossl eyepieces (typically 52°) or Erfle eyepieces (around 60°), the WA-66 offers a noticeably greater sense of space and makes it much easier to find and track objects.
Image correction is surprisingly good for telescopes with a focal ratio down to f/6 - stars remain sharp practically all the way to the edge of the field. On instruments with a shorter focal ratio, some minor aberrations may appear at the very edge, but this is a common characteristic of most eyepieces in this price range.
What can you observe with the 9mm focal length?
The 9mm focal length makes this a versatile eyepiece for medium magnification, suitable for observing the Moon, planets and deep-sky objects. The wide field of view makes it significantly easier to navigate the sky and locate faint deep-sky targets.
Who is this eyepiece for?
The Sky-Watcher WA-66 9mm is an ideal choice for:
- Beginner astronomers who want to upgrade beyond the standard eyepieces included with their telescope
- Experienced observers looking for a reliable eyepiece for the medium magnification range
- Anyone who needs a durable backup or travel eyepiece thanks to its solid metal construction and manageable weight
An eyepiece suitable for visual astronomy at a reasonable price - the Sky-Watcher WA-66 9mm is a solid, well-equipped optic that will not disappoint. Whether you are expanding your eyepiece collection or replacing a weaker eyepiece that came with your telescope, this is a choice worth considering.
Technical specifications
| Parameter |
Value |
| Focal length |
9mm |
| Apparent field of view |
66° |
| Barrel diameter |
1.25″ |
| Optical design |
5-element wide angle |
| Coatings |
Multi-layer anti-reflection on all surfaces |
| Body material |
Metal |
| Filter thread |
Standard 1.25″ |
| Eyecup |
Adjustable fold-down |
| Suitable for telescopes |
f/6 and slower (minor edge aberrations possible at f/5 and faster) |
