The Celestron 15 x 70mm SkyMaster binoculars are a surprisingly economical tool for revealing the splendors of the heavens at night and the intricate secrets of distant wildlife during the day . . .For astronomers, the 15 x 70mm SkyMaster is almost the equivalent of a low power 100mm rich field telescope. Using two eyes to observe, however, shows you up to 40% more detail than you see looking through the single eyepiece of a telescope. With a wide 4.4 degree field of view, you can sweep the star clouds of Sagittarius, search out the Great Galaxy M31 in Andromeda and the Pinwheel Galaxy M33 in Triangulum, take in globular clusters like M13 and M22, open clusters like the Beehive and the Wild Duck, and much more. A supplied separate tripod adapter lets you mount it on any convenient camera tripod (at 48 ounces, it is realistically too heavy to hand hold steadily enough for extended observing). The tripod adapter mounts on any standard 1/4"-20 thread 35mm or video tripod. You can use the adapter with many other binoculars, as well as the SkyMaster.
For nature study, the 15 x 70mm SkyMaster will let you observe deer feeding in distant meadows early in the morning, mother birds feeding their chicks in nearby nests, courtship behavior in distant off-shore rookeries, and more. With a close focus of 43', this is not a binocular for warblers or butterflies (unless you are watching them from across your backyard). However, its bright 4.7mm exit pupil makes it a good and very economical choice for any twilight birding or nature study activity where close focus is not required - but bright images are essential.
Eye relief is specified at a very long 18mm. While this is technically correct, the actual usable eye relief typically measures a mm or two less due to the recessing of the eyepieces when the eyecups are in the down position for eyeglass use. A shorter eye relief than specified is typical of all binoculars. There will be some minor vignetting of the field for those who must wear eyeglasses while observing. Soft roll-down eyecups shield the unaided eye from stray light when rolled up, and cushion eyeglass lenses when rolled down.
The supplied neck strap is narrow. Adding an optional wide padded neck strap would make carrying the SkyMaster more comfortable.
This center focus Z-body porro prism uses BaK-4 prisms and multicoatings for good light transmission. It comes with a lightweight soft storage case, objective lens covers, and an eyepiece rainguard. Light rubber armor with textured rubber gripping surfaces and thumb grooves provides a sure hold when dewing becomes a problem. The 15 x 70mm is water resistant, but not waterproof. Setting it down in dew-soaked grass would not be recommended.
There is some barrel distortion (straight lines at the edge of the field are curved), and some visible astigmatism and chromatic aberration at the edges of the field. However, these flaws are not obtrusive, particularly in view of the large aperture and exceptionally low price. As a first serious astronomical observing tool, as a long distance nature study instrument, or as a highly useful companion to take into the field with your telescope at night, the Celestron 15 x 70mm SkyMaster is priced to be easily affordable for any birder or astronomer.
