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The ES 14mm: This is a large 2-inch barrel 9-element wide-field eyepiece that truly does have an apparent field of view that is one of the widest in existence. The eyepiece is a massive beast that is about 6.25 inches long and 2.75 inches wide. It weighs in at a whopping 856 grams (1 lb, 14 oz.), which is a bit heavier than the 13mm Tele Vue Ethos, but lighter than the 31mm Nagler. This weight will be a significant factor for those who wish to use the eyepiece in Dobsonians that are not well balanced or which move in altitude easily. The eyepiece is one solid unit made mostly of black anodized aluminum, with slightly conical ends and a 2-inch standard barrel which is tapered for safety rather than just undercut. The body section has a wide knurled rubber section for better gripping action. The eyepiece comes with an extendable rubber eyecup as well as standard threading for filters on the barrel. Using my crude optical bench and drift testing, I came up with the following approximate specifications for the ES 14mm eyepiece:
14mm ES Eyepiece Specifications
Dimensions: 6.25” x 2.75” (2” O.D. tapered barrel)
Weight: 856 g (1.875 lbs)
Measured Apparent Field of View: 101 degrees (+/- 0.5 deg.)
Effective Field Stop Diameter: 24.47 mm (based on drift test)
Approx. Eye Relief: 14.5 mm