Focal Length: 7mm, 82° field of view
Supplier: The Widescreen Centre
Telephone: 020 7935 2580
The William Optics UWAN 7mm, we soon realised when we tested it, is a good little performer.
The model is outwardly similar to the Nirvana UWA-82° – apart from the William Optics swan logo on the rubber dust caps and branding on the etched barrel ring, they are almost identical – but comparing the reflection of a light bulb in each eyepiece’s optics to check for multicoatings revealed that the internal optics of these two eyepieces have a different specification.
Closer inspection indicated that different-sized lens elements have been selected.
Stars were sharp across the central field of view, and the view didn’t deteriorate until very close to the field stop.
There was no aberration of colour in the central field and we found the contrast to be good, which may have been down to the multicoatings.
This meant our views of the Pleiades star cluster revealed plenty of bright nebulosity against a dark background.
The UWAN has a 9mm-high twist-up eye shield that has a nice smooth action.
Extending the eye shield to full height doesn’t put any strain on the focuser, thus ensuring it doesn’t shift position.
To sum up, this high-quality compact eyepiece gives more expensive competitors a good run for their money.
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This review appeared in the February 2010 issue of Sky at Night Magazine