Binoculars (Part 3)
Posted by Brian Ventrudo
Although they are expensive, imaged-stabilized (IS) binoculars give stunning low power views of the sky without the dreaded image shake of standard binoculars. It’s hard to read a review that doesn’t rave about these technical wonders for astronomy or terrestrial use.
• Nikon, Canon, and Fujinon, among others, offer some type of image stabilization. Canon models seem to have the widest following among amateur astronomers.
• Piezoelectric motion sensors detect the pitch and yaw movements in the binoculars. The motion signal feeds into a microprocessor, which initiates image stabilization by controlling a vari-angle prism – a pair of glass plates joined by flexible bellows. The space between the plates is filled with a silicon-based oil to maximize image deflection.
• The motion sensors work in light or total darkness and operate at any orientation, so there are no restrictions on where the binoculars can be pointed… up, down, sideways, anywhere.
A Deeper Look
• When you switch on the IS feature, the image does not “freeze”, but rather wanders slowly enough for your eye to follow. And the IS works when you sweep across a field of view, although there is a slight hesitation.
• These devices are battery hogs. You can burn through a pair of alkalines in 5 minutes on a cool night. With rechargeables, you might get 2 hours. Of course, you can turn off the IS feature when you’re not using it.
Good To Know
In a 2006 review of Canon’s 10×42 IS binoculars, Gary Seronik said “These are simply the finest binoculars I have ever used for astronomy”.
Image shake in regular binoculars led me to abandon binocular astronomy many years ago. But one look through Canon’s small 10×30 IS rekindled my interest in binoculars. If you have dark-sky and if you can afford a pair of IS binoculars, I highly recommend them.