TelescopeBinoculars.org

Binoculars won’t show you much more of the planets than what you can see with the naked eye. You’ll be able to see Jupiter’s four Galilean moons, and Uranus if you know where to look, but the planets will still just be bright points of light. They *will* show you a lot more stars, as well as a number of assorted fuzzy objects (star clusters and a few galaxies and nebulae) that will make interesting targets for your telescope when you get it. Binoculars are a great way to start learning the sky, and can be helpful in finding targets for the telescope. They also have daytime uses.

$30 is scraping bottom for binocular prices, but I have seen some cheap Bushnells in that price range that were decent. If possible, try the unit you’re going to buy first, or at least make sure they’re returnable, as quality control is iffy at this price point. Make sure the image is reasonably sharp and clear, and that the tubes are aligned. If you feel a bit cross-eyed either while viewing or immediately after, they’re out of alignment and will be uncomfortable to use. Get at least 35mm objectives, and preferably 50mm. Smaller objectives are too dim to show much at night. Also avoid zoom binoculars and "ruby" or other dark coatings.

Sorry, but at that price point you really won’t find anything very good. You may get something that will feed your interest in astronomy (and thus are worth getting as a temporary fix), but you won’t get anythign of quality. You could always try the local classifieds to get something decent that is used – cheaper and no taxes. A set of 10×50′s is a good starter set (10x magnification, 50mm lenses on each tube). They will show you some detail on the moon, and some of the brighter nebula (eg. Orion nebula) galaxies (eg. Andromeda) and star clusters (open and globular). But don’t get your expectations up about their capabilities – especially when it comes to planets. You will see no detail on any planet at 10x magnification (and higher magnification binos mean you can’t really hand-hold them steady). You will be able to see 4 dim ‘stars’ in a line by Jupiter – these are actually the four biggest moons of jupiter – but no other planet will really be anything other than a bright point of light. This isn’t to discourage you from getting bino’s – they are a great tool within their limitations – but your idea of observing asteroids with them makes me think that you need to keep your expectations realistc.

And when xmas rolls around, be careful what you get. One of those Dept store crap-o-scopes can do more harm than good to a young astronomer. They can be so frustrating to use (poor mounts and focusers) that they can be very discouraging. I would recommend a small dob as your first scope (4.5" or 6"). When you point them at something, they are actually stable and keep the object in the field of view – which is a basic requirement of a decent scope, and unfortunately more than most cheap tripod-mounted scopes can manage.

I generally don’t recommend any binoculars under around $100. Binoculars are precision instruments, and they need good solid construction to hold their collimation and decent achromatic optics to deliver sharp colour-free views, especially for astronomy. For $30 you get cheap plastic construction and even plastic lenses, just a kid’s toy.

If you’re lucky, you might find a half-way decent pair of binoculars for that price at a yard sale. Check your local newspaper and make the rounds of all the yard sales in your area. For $30 retail you’re only going to get a toy suitable for kids playing soldier.