If you’re purchasing an astronomy gift for someone whose interest may not stick, binoculars are an economical choice with uses beyond astronomy. Even if you already have a telescope, a good pair of binoculars can be a useful addition, and they will cost less than most eyepieces. A pair of 40–60mm binoculars will offer a wide field of view, can be set up quickly, and are capable of showing open star clusters, bright nebulae, and galaxies. Smaller handheld binoculars can be used as a reference or practise when trying to locate new objects in your telescope. Some observers prefer tripod-mounted, larger binoculars over telescopes because they are more comfortable to look through with two eyes and are 75% brighter than an equivalent aperture telescope. This factor is also why a pair of binoculars is superior to a cheap telescope with a small aperture and poor features for beginners, as a pair of bargain 7x50 or 10x50 binoculars will have superior image brightness to a 2-3” telescope. You won’t have to worry about bad optics, a wobbly tripod, or low-quality, uncomfortable eyepieces with even the cheapest acceptable binoculars in our rankings.
Zoom binoculars tend to have lower image quality compared to fixed-magnification binoculars. This is because the additional moving parts and lenses required for the zoom feature can introduce distortions and aberrations into the image. Additionally, zoom binoculars often have a narrower field of view and less light-gathering ability than fixed magnification binoculars, which can make it more difficult to locate and observe objects. The high magnifications offered are rarely of any use, being too shaky to use handheld, and if you’re bothering with a steady mount and tripod, a telescope is a better choice. Another issue with zoom binoculars is that they are generally less durable and more prone to failure than fixed-magnification binoculars. The additional moving parts in zoom binoculars can be prone to wear and tear and may require more frequent repairs or maintenance.
“Ruby-coated lenses” are often used to block out certain wavelengths of light to hide shoddy optical quality in binoculars. This reduces light-gathering ability and is also a general indication of a low-quality unit to begin with. Avoid any binoculars with such claims, even for non-astronomical use.
Binoculars with an aperture smaller than 35mm should be avoided due to both quality concerns in lower-priced units and the lack of capabilities offered by such smaller apertures.
“Perma focus” and other similarly advertised binoculars are an attempt to sell low-quality units that lack a focus mechanism as somehow advantageous. They are essentially a scam; avoid them.