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Light Curves, Spectra, and Images

Tools for All Astronomers

Because most of the objects that astronomers observe are so far away, we cannot touch them. Observing the light that they emit is often the only means we have of understanding them. Studying the light that comes from a source can tell us a great deal about what kind of object it is -- we can measure the energy of the light coming from the source, we can measure the amount of light coming from the source, and we can make an image of the source. If we graph the amount of light at different energies, we can make a spectrum. We can also measure the brightness of the source over time, making what is called a light curve. By making an image of the source, we see what it looks like.

The concept of an image is probably the most familiar -- telescopes like the Hubble Space Telescope produce many beautiful images. But images can also be made using light we can't see with our eyes, such as infrared or ultraviolet. Graphical data, like spectra and light curves, are very valuable to astronomers as well. Among other things, a spectrum can give us information about an object's composition, mass, and motion. A light curve can analyze short-term or long-term changes in the brightness of a source -- useful for bursting objects, binary systems of stars, and pulsars. Click on one of the below links to learn more about light curves, spectra, and images!

    * Use Hera to analyze light curves, spectra and images.

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

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Acting Project Leader: Dr. Barbara Mattson
All material on this site has been created and updated between 1997-2012.

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