Telescope Reviews: Handheld Binocs for Astronomy

Well, for me, that question has a trivial answer. My own eye's pupils only open to 5.5 mm or so, so I can't take advantage of a 7-mm exit pupil. For me, 9x60 binoculars would be functionally identical to 9x50 binoculars -- or nearly so. So why not save money and weight, and get the smaller binoculars?

But even if your pupils do open to 7 mm or larger, I'd suggest the 12x60's over the 9x60's. The general rule is that magnification matters more than aperture in determining how faint you can see and how much detail you can see.

That's true even when the view is grossly wobbly. I was somewhat surprised to discover this, but it's definitely true. I used to own image-stabilized 15x45 binoculars, and when I compared them to my 10x50 binoculars, hand-holding both units while standing and without using the image stabilization, I could see much more on each and every target through the 15x45's.

That's why I described wobbles as an aesthetic issue rather than a practical one. An equal amount of wobble is a whole lot more obvious at 12X than at 9X, and you may find it so annoying that it really bothers you. But you'll still see more through the 12x60's -- a lot more.

The other downside of high magnification is smaller field of view. But you can always fall back on your 7x35's if you want a really wide field of view.

As for viewing from a seated or reclining position -- if you haven't tried it, you don't know what you're missing. Quite aside from wobbles, there's a major aesthetic issue. To me, one of the big benefits of binoculars is that you get to face your target head-on, with ample sky all around it. And that's simply not possible if your neck is craned back at a 90-degree angle.

Moreover, once you get into the 12x60 arena, you're likely to find that many astronomical targets take on a life of their own, and you want to study them at leisure. That's difficult or impossible for me when I'm standing up with aching feet and aching neck.

Granted, lugging out a reclining chair is a nuisance. But a normal chair is part of any good observing setup. And lying down flat on the ground requires no equipment at all, and takes just a second or two.

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Tony Flanders

First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.

Edited by Tony Flanders (01/03/08 02:43 PM)