How does a Dobsonian telescope magnify?

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All I know is that it’s collecting a large amount of light and converging all of it through the eyepiece. But shouldn’t that show the celestial body at its apparent size? Like a Refracting telescope uses lenses to magnify it right but how does a Dobsonian telescope do that?

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The key word here is *converging*. Bringing lots of light rays together with a curved mirror is exactly the same as doing so with a lens.

If you look at the diagram of a Newtonian telescope you will see parallel rays coming in the front, becoming converging rays at the eyepiece. This means that a very small patch of sky occupies a large part of the field of view of the observer.

Note though that magnification is not the primary function of astronomical telescopes, accumulating lots of light is. Sky objects are often big enough to see with the naked eye, they are just too dim.

Reflecting telescopes, including Dobsonians, use a curved mirror to provide magnification. In the same way that car rear view mirrors are often curved and make objects look smaller, telescope mirrors are curved the opposite way and make objects look larger.