| The Nikon 10 x 70mm SP Astroluxe binocular uses “SP" (Special Performance) extra-low dispersion glass for bright, wide field deep space images that are virtually free of spurious color. Astigmatism and distortion are likewise very low, the field of view is quite flat, and the images are bright indeed. These performance characteristics make it ideal for astronomical observing, if your eyes can still dilate to the 7mm of your youth. Those astronomers who are middle age or older, whose eyes can no longer dilate to a full 7mm, will find that some of the light of the binocular’s 7mm exit pupil will fall on the iris of their eye and be wasted, rather than entering the pupil itself. If your eyes won’t fully dilate to 7mm, we’d recommend against this binocular. The 5.1 degree field of the 10 x 70mm makes it an excellent choice for observing large deep space objects, such as the 3.5 degree wide Andromeda Galaxy, the Veil Nebula, etc. The brightness and clarity of the binocular also makes it very useful for medium distance low light birding from a fixed location. Mounted on a tripod with optional tripod adapter #7806 (the binocular is realistically too heavy to hand hold), this is a good binocular for observing nesting eagles in twilight, off-shore rookeries, waders at dusk across an estuary, etc. As with any binocular, the use of both eyes to observe can reveal up to 40% more detail than one eye alone, as when using a spotting scope. Two-eye viewing is also more comfortable than one-eye squinting through the single eyepiece of a spotting scope. This makes the 10 x 70mm Nikon a viable alternative to a 70mm or 80mm spotting scope in many low light observing situations, although the relatively low 10x magnification will limit its usefulness in long distance terrestrial applications. Its low chromatic aberration (thanks to its SP glass), low astigmatism, and very flat field make it a pleasure to look through. If you need a big aperture binocular for astronomical observing, the 10 x 70mm Nikon is an excellent choice. Features of this binocular . . . B-body porro prism with individual eyepiece focus. BaK-4 prisms for high light transmission, with no prism edge vignetting. Rugged die-cast light alloy body with pebble-grain leatherette coating for a secure grip. Dry nitrogen filled and O-ring sealed to be fogproof in all temperature extremes (very desirable for astronomical observing) and fully waterproof, although Nikon does not recommend full submersion. Inert nitrogen filling also prevents the internal formation of fungus in high humidity climates. All optical surfaces (including the BaK-4 prisms) are fully multicoated with proprietary Nikon coatings for high light transmission and contrast. There is no 1/4"-20 thread tripod adapter socket. The optional #7806 adapter bracket for attaching the binocular to a tripod clamps around center hinge rod of binocular instead of screwing into the end of the rod. Two sets of rubber eyecups are provided. One is a pair of conventional rolldown eyecups for eyeglass use. The other is a pair of soft batwing-type eyecups with extensions to shield no-eyeglasses eyes from ambient light and provide higher contrast.
|