These amazing images of space would not be possible without a very important piece of equipment.
Distant objects appear faint and small, but telescopes allow us to gather lots of light from them, so that we can see a brighter, clearer, and larger image.
The first optical telescopes were made around the year 1608.
Telescope Inventors: Hans Lippershey, Zacharias Janssen
Their simple design took advantage of the fact that light waves can be refracted.
Refraction – light waves bend. Passing from one medium to another
Refracting telescopes consist of a convex lens and an eyepiece.
Refracting Telescope, Convex – curved outwards
Light enters the telescope through the lens, which causes it to converge before passing through the eyepiece.
The image then appears magnified to the observer.
It was this type of telescope that Galileo pointed towards the skies.
Galileo Galilei, Father of modern astronomy
In 1616, the first telescope to utilise light's reflective properties was developed.
Reflection – Waves bounce back from a surface
By 1668, Isaac Newton had improved its design.
Sir Isaac Newton, Improved the Reflecting Telescope
Parallel rays of light enter the telescope and bounce off of a concave mirror.
Reflecting Telescope, Concave – curved inwards
The light then reflects off a second mirror, before entering the eyepiece where
These days, telescopes of all shapes and sizes are used by professionals and amateur astronomers.
They all work on these basic principles, though most of the biggest ones now use detectors, such as cameras and sensors, to record their images.
Telescopes are not just used to improve our view of visible light in space.
We can now use them to look at the whole spectrum, from radio waves through to gamma rays.
Telescopes have enabled us to truly see the wonders of the Universe.