Modern Detectors

How’s it going? We are nearly 1/3 of the way through our class, and I want to hear what you think so far. Could you please take a minute to complete this anonymous student feedback form? I read every response - your feedback is really important to me. Ok, thank you. Now let’s learn about the amazing cameras that make modern astronomy possible!
Watch Catching Starlight - an excellent introduction to astronomical detectors from our friends at the European Southern Observatory.
Explore 6.3 Visible-Light Detectors and Instruments to learn about the various types of visible-light detectors, including the human eye, photographic film, and CCDs.
Digital cameras have played an essential role in revolutionizing the science of astronomy. Watch the teacher video CCDs, Pictures, and Pixels, which describes how digital cameras work.
Digital pictures are simply a table of numbers containing the x and y position of each pixel as well as the number of “counts” found in each pixel. These “counts” relate directly to how many photons of light hit each pixel. Since astronomers use these images for their data, they are recorded in a special type of file format called “.fits”. Only certain programs can open and display astronomical .fits files.
You may be surprised to learn that all astronomical pictures are captured as black and white images. Then, where does the color in astronomical pictures come from? Begin by watching the teacher video Color and Astronomical Pictures, which introduces how various colors are made and captured in astronomical images.
Let’s learn more about the filters that astronomers use when collecting their images. Watch the video Filters in Astronomy and experiment with the Light and Filters Simulator for yourself.
We have an intuitive understanding of what it means to take pictures in visible light (or even in infrared and ultraviolet), but as you will see in our course, astronomers can even capture pictures in radio! Wait, what? (Remember, “radio” is a part of the EM spectrum - it is light, not sound!) What does a radio telescope look like? Review 6.4 Radio Telescopes to understand the principles behind radio astronomy, the use of radio telescopes and interferometers for enhanced resolution, and the advancements in radar astronomy.