Astro-Tech 21mm UWA 82° 2″ Eyepiece

This Astro-Tech 21mm waterproof eyepiece is a substantial 2″ eyepiece that will give impressively sharp and contrasty wide field views of nebulas, compact open clusters, globular clusters, etc. with virtually any telescope that can use 2″ eyepieces

This 82° 21mm Astro-Tech UWA eyepiece is an excellent low/medium power ultra wide field eyepiece with an outstanding price.  

Many observers feel that a 82° field eyepiece like this Astro-Tech hits the “sweet spot” between the affordable, but “looking down a tube” view of conventional 45°-50° field eyepieces, and the full-immersion, but very expensive, observing experience of an ultra-wide field premium 82° or 100° eyepiece.

The optical designers used the latest computer design programs to optimize its performance. Its six element/four group design uses low dispersion and high refractive index lenses and full multicoatings for high contrast, high resolution, and flat field images across a very wide 82° field of view. The lens edges have been blackened to improve contrast.  The eyepieces are parfocal within the UWA series.

The 2″ 21mm Astro-Tech is designed for the serious deep space explorer – no matter what your telescope type. For example, the 21mm Astro-Tech will give you a .86 degree field at 95x with the 2000mm focal length of either a big 17.5″ f/4.5 Dobsonian or an 8″ f/10 Schmidt-Cassegrain. That’s over 1 and half lunar diameters and is ideal for observing emission and reflection nebulas and nebula remnants.

At 14mm, the eye relief is good, although eyeglass wearers will still see a minor vignetted image. This isn’t as much a problem as you might think, as the 82° field of view is so wide that even non-eyeglass wearers have trouble seeing the whole field at once. This is an eyepiece that shows you a “lost in space” view of space for a true full-immersion observing experience. With its unconstricted view, your eye relaxes, allowing you to easily use the “averted vision” technique to study faint details across a huge field of view.

The eyepiece has a soft fold-down rubber eyecup and comes with dust covers for both ends of the eyepiece.

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