Astronomy light sources are the most common sights on our own planet. Stars and planets in our solar system emit both radiation (which we can observe with the naked eye) and glows of various colors. If it were not for these, the universe would be a very cold place indeed. The other great thing about astronomy is that it’s not just looking at a star or planet and absorbing its light. It’s trying to capture it, keep it stable, and measure it very carefully.
How do you do this? There are many different ways and instruments that have been developed specifically to do just this. A few of them can be mounted on a telescope to take a photo or take a video recording of the object of interest. Others are computer aided and act as a Doppler radar, producing very precise images.
What if you want to measure a very faint light? Well, radio telescopes can help. Radio waves are ripples in space even radio waves emitted by stars are ripples in space and by measuring the Doppler shifts of these radio waves, an astronomer can get a very accurate measurement of the thickness of space. This is known as an optical/radio astronomers are often able to measure Doppler shifts at a quarter of a millimeter or less.
There are also things called infrared telescopes, which have been developed to take infrared pictures of stars. These have a variety of different tools that work, depending on the kind of infrared image that they’re looking for. Some use a combination of mirrors and lenses to focus a very tiny piece of light into a much bigger spot. Others use extremely sensitive detectors that can detect a minuscule fraction of a millionth of a millimeter of a very hot gas.
These incredibly powerful instruments use very precisely defined methods of acquiring and using the light. They look through the gases to locate the light that’s being emitted. It’s then a process of averaging the light that’s coming in to the telescope and passing it through a filtering medium to remove any other stray light. Once the average is done, the images are formed and are shown on a display screen. A telescope like this can peer deep into a space about ten times larger than the full moon and is used to study very faint objects and galaxies.
When looking up close to celestial objects, astronomers use telescopes that are smaller and more versatile than those used for planetary science. They are, however, not only capable of this type of observation. They also make observations of very faint nebulae, which are like comets but have very low gravity. It takes a very precise instrument with very precise measurements to determine something as small as a fleck of dust. So far, astronomers have made some remarkable discoveries thanks to the light that has been reflected back from very distant space.