Choosing a Binocular for Astronomy
When choosing a binocular for astronomy you first need to understand how binoculars work. Similar to telescopes, a binocular needs to gather light. The same critical feature for telescopes is the same in binoculars - you need a large enough objective lens to gather light.
Binoculars are measured with two key features - its magnification and its objective lens. For example, a binocular may be listed as 10x50. The first number 10 is the magnification of the binocular. The second is the size of the objective or outside lens in millimeters. 10 times the naked eye with a 50mm objective.
Like telescopes, objective is the most important factor. It's the same for binoculars for astronomy. We recommend a minimum of a 50mm objective lens for astronomy. A 7x50 or 10x50 are very common choices for astronomy. They offer a large enough objective lens and a magnification that is enough to bring objects close enough to observe.
Even better for astronomy is the larger objective lens binoculars. Many astronomy binoculars will features objective lenses between 60mm to 100mm or even more. These larger binoculars will usually require a tripod, as they are very heavy. The larger objective size binoculars will often have much more magnification than traditional sized binoculars. Powers of 10x, 15x, 20x or more are common on larger astronomy binoculars. When you have binoculars of this size and magnification - having a steady hand is usually not enough. Having them mounted on a tripod will give you the best results. Many giant binoculars will have a built-in tripod mount or have an adapter included or sold separately.