Telescopes are instruments that are used to help you see objects at a distance, and are usually used for viewing the sky (astronomy) or land (terrestrial). A telescope allows you to see details at a distance mostly by collecting light (as opposed to magnification). The telescope collects light through a lens or a mirror. The sport ter the telescope is at collecting light, the sport ter you are able to see the details of what you are looking at in the distance.
There are three basic types of telescopes. The first is refracting telescopes, refracting telescopes use an objective lens to collect light. The second is reflecting telescopes, which use a mirror to collect light. The third is Catadioptric telescopes which use both mirrors and lenses to collect light for the telescope. But these inner lenses are not the only ones at work, while the telescope collects light and focuses the object you are viewing, the eyepiece is magnifying the object you're viewing.
Telescopes are highly customizable objects, so you can change the various pieces on your telescope to your personal needs. Once you buy the telescope, you can purchase a variety of different eyepieces for most telescopes. For example, low-powered wide- field eyepieces are good for viewing land, while high-powered eyepieces are good for seeing details on the moon. You can find mounts for holding your telescope in place. There are camera adapters that allow you to take pictures of what you see through the telescope. There are manual and computerized tracking devices to help you follow the object you are observing even as it continues to move.