FlELDS OF VIEW
The field of view is usually stamped on binoculars, but may be given as "feet at yards." For example, 367 feet at 1,000 yards equals a 7 de-gree field of view, and 262 feet at 1,000 yards equals 5 degrees.
Most 7x binoculars take in about 7 degrees of sky- roughly 14 times as big as the Moon- while 10x models see a smaller area, about 5 degrees.
Special wide-angle models provide impressive views of 8 to 10 degrees. But there are trade-offs: stars at the edge of the field tent to distort, and your eyes need to be close to the eyepieces.
Zoom binoculars sound attractive at first, but in almost all cases they are crippled by inferior optics and restricted fields of view.