This Astro-Tech 25mm Paradigm Dual ED is an excellent medium to low power eyepiece for encompassing open clusters, picking up detail in emission and reflection nebulas while still viewing them in their entirety, etc. This high quality 25mm focal length optical gem will visibly upgrade the performance of the usually only so-so 25/26mm eyepiece that typically comes standard with most telescopes. It is also a good choice to complement the 40mm eyepiece provided with some go-to Schmidt-Cassegrains. The 25mm Astro-Tech Paradigm is usable with any telescope type, under virtually any seeing conditions - from fair to superb. (Rain, snow, or fog might limit its usefulness, however.)
With a short focal length refractor it is a low power eyepiece well suited to scanning the crowded star clouds of Sagittarius, observing galaxy clusters, framing the more compact emission nebulas with the black of space, observing the nebulosity around the Pleiades, etc. With the 430mm focal length f/6 Astro-Tech AT72ED, its six lens/four group two ED lens optics provide a magnification of 17x, a field nearly seven times as wide as the full Moon, and a 4.16mm exit pupil that is ideal for rich field observing.
The 25mm Astro-Tech Paradigm is also a good choice for medium power observing with long focal length refractors, reflectors, and catadioptric scopes. On an 8" f/10 catadioptric, for example, it yields 80x, with a 0.75° field that is half again as wide as the full Moon. This is a very useful magnification for observing compact planetary nebulas and globular clusters, as well as lunar observing. Its high contrast makes observing small features along the lunar terminator a nightly delight as the terminator creeps across the face of the Moon.
The six lens/four group design and two ED (Extra-low Dispersion) glass elements of the 25mm Astro-Tech Paradigm provides all of the optical virtues described at the top of this catalog page - high contrast, a sharp and flat field from edge to edge, excellent color fidelity, and exceptionally low astigmatism and barrel distortion. It has a usable eye relief of 15mm. Combined with the twist-up eyecup design, the good eye relief makes it a sensible choice for eyeglass wearers.
This Astro-Tech 25mm Paradigm Dual ED eyepiece will upgrade your scope's starter eyepiece, bringing new life to your nightly views of the heavens. The 25mm Paradigm will change your mind about just how good low power viewing with a telescope can be, with truly high-end optical performance at a not very high-end price.
