The difference between Binoculars and a classical Telescope is how they are built and in their intended use. The word Binoculars means two eyepieces, they are of compact design, portable and can be quickly used for viewing. Telescopes are Monoculars: they have one eyepiece, are bulky need a tripod and mounting and are intended for the observation of astronomical objects.
Binoculars are in general used for terrestrial observation. In principle, they are two small telescopes that are mounted parallel to each other and which point into the same direction (collimated). To not project an upside-down picture, they have an additional internal extra lens (erecting lens) or more common in modern binoculars a pair of prisms build in. A telescope used for celestial observation does not necessarily need to show an upright image.
Today the term telescope is not just used in the classical sense anymore. Any kind of device used in Astronomy is called a telescope, whether it collects visible light, radio waves, game rays, or x-rays. Even the latest Gravitational wave detector (GOTO) is simply described as a telescope.
There is a very large selection of binoculars and telescopes available, from small compact pocket binoculars to highly complex space telescopes. What model and design are best to choose, depends entirely on where and for what purpose they are to be used.
Binoculars are usually relatively small and lightweight compared to telescopes and can be easily transported. Thanks to their compact dimensions binoculars can be kept in bags, pockets or around your neck. They will quickly be at hand when needed for observing animals in the wild or viewing any distant object of interest.
Binoculars are used for nature observation or surveillance but they are also used for astronomical purposes. Binoculars are used by astronomers for scanning the sky quickly to find a particular object. They are also very useful or for observing very large objects in their entirety such as the milky way.
As both eyes are used for viewing, binoculars project a 3D image and provide a better in depth perception and a broader field of vision. However, the binoculars much smaller aperture compared to the aperture of a telescope limits their use in poor light conditions and has them work best during the day.
Most binoculars are very easy to use, point at an object and focus. To use a telescope reading the manual and familiarization with their respective features is necessary.
quickly scan large portions of the night sky
portable, easy to handle
best suited for terrestrial viewing
no detailed viewing of celestial objects
Telescopes are the heart of astronomy. They are used to observe planets, stars and other objects in the universe. Their high magnification allows detailed observation of, for example, craters and mare of the moon, planets of the solar system or other distant celestial objects.
Even Telescopes for hobby astronomers are often large and bulky and are not easy to carry around. Most telescopes need a fixed stationary set up. Many hobby astronomers go as far as building a little observatory in their backyard or on the roof of their houses.
One of the most important features of a telescope is the aperture, not the magnification as beginners always misunderstand. The larger, the more light can be collected and dimmer objects may be observed. Binoculars are limited in this respect. The large telescope aperture is also the key feature to provides a crisp and detailed image.
Telescopes, depending on the design are available from are small to very large. For the beginning hobby astronomers, a 3-4 inch Refractor or a 4-5 inch Reflector is a good size to start. Larger and more powerful telescopes are the option for the experienced hobby astronomer.
detailed viewing of celestial objects
cameras can be attached
not really suitable for nature or terrestrial viewing
A good pair of binoculars with its large field of view helps to scan the sky and to quickly find an object of interest. It is the right tool to hunt for Komets or to admire the beauty of the milky way.
A telescope allows seeing details on the moon or our neighboring planets in the solar system. Also, distant galaxies and other dim and distant objects in the night sky that require magnification and light gathering power can be observed.
There is no real debate whether a telescope or binoculars are better. Too different are their purpose and their applications. Every Astronomer utilizes both as the complement each other.
What is more important than just viewing objects through binoculars or telescopes, is to know what you are actually looking at. The fascination of celestial objects comes through comprehending what they really are.