What Can You See With Binoculars?
[This is episode 2 of I-have-no-idea in a series on buying and using binoculars]
What can I see with my new binoculars? This is a common question, but I’m a smartass and I usually respond, ‘Anything you point them at.’
What people really mean to ask is, ‘What details can I see with binoculars that I couldn’t with my naked eye?’
Oh, well why didn’t you say that in the first place? Step over here and I’ll tell you…
As I mentioned in my previous post, binoculars provide relatively low magnification compared to telescopes, but they have the virtue of being portable and convenient to use. Binoculars generally have magnifications between 5 to 20 power, with anything over about 10 power requiring a tripod.
The amount of detail you can see from binoculars is actually a function of the objective lens and NOT the magnification. The only positive effect magnification has is to make the image bigger, but it also makes the image dimmer, fuzzier and makes it really hard to hold the binoculars steady. Here is a post I made long ago about magnification.
Bigger objective lenses collect more photons from the sky, making things brighter. That’s really what you want, way more than magnification. Higher powers just make the details a little larger so you can see them better, but it comes at the expense of brightness.
As with all things in life, it is good to strike a balance. Typically, what you want to strive for is the brightest image you can get with a magnification that doesn’t make the image too fuzzy and shake all over the place.
For hand-held binoculars, that balance is 7×50’s. That is the best configuration for general purpose use. With those, you can see details on the moon, including shadows from the mountain ranges, the phases of Venus, the red color of Mars, the rings of Saturn, and sometimes the belts around Jupiter. The Orion Nebula is a large, gorgeous smudge in binoculars, as is the Andromeda Galaxy.
All naked-eye comets, like the recent Comet McNaught are absolutely brilliant in binoculars. I use binoculars for looking at comets more than anything else, including my telescopes. They are great for running outside and quickly checking out if the comet is doing anything cool.
For tripod-mounted binoculars, a pair of 11×70’s will show you all of those things, but brighter. These binoculars are very expensive, about $300.00, and really can’t be used for anything but looking at the sky. None of the really faint deep-sky objects, like The Crab Nebula, are visible with binoculars, unless you’re the Six Million Dollar Man.
Binoculars are a really easy, portable solution for just quickly looking up and finding out ‘what the hell is that bright spot in the west?’ or getting a quick look at a comet or the moon. For anything longer and more in-depth, I’d spend some money on a small telescope instead.
Next stunt: why you need a tripod.
Technorati Tags: backyard observatory, binoculars, telescopes
Related Stories
POSTED IN: telescopes
2 opinions for What Can You See With Binoculars?
Nick
May 25, 2007 at 3:58 am
Nice article Tony - I think the targets I find most rewarding with binoculars are the larger open star clusters, particularly the Pleiades, the Hyades and Praesepe - the wider field of view generally frames these better and gives you a beautifully expansive view compared with the close-up view at the eyepiece of your telescope.
Tony
May 25, 2007 at 10:30 am
Hi Nick,
Good point about the open clusters. They usually appear quite bright and colorful in binoculars, they’re an excellent thing to look at with them. One of my favorites is the double cluster in Perseus. Here’s a good image:
http://apod.nasa.gov/apod/ap051011.html
The Pleiades are quite amazing as well. Thanks for pointing that out…
Have an opinion? Leave a comment: