Not all telescopes invert their image - it depends on the design! Indeed the telescope Galileo used to observe the moons of Jupiter provided an upright image. read more
In telescope we use use Convex lens which forms inverted image of original image.We can obtain the original image by adding extra lens.But the device becomes expensive and bulky.Regarding stars it is not important whether inverted or not. read more
When you view an automobile upside-down, you recognize that this is not correct. Lets talk about the different types of telescopes and how the orientation of the image is observed through them and what you can do to correct it for land use. Refractor and Cassegrain telescopes will produce an image that is upside down when used without a diagonal. read more