Q&A: Chandra Mission
How sensitive is Chandra?
Chandra is sensitive to energies of about 0.2 to 10 kiloelectron-volts, or keV. This corresponds to a wavelength range of about 1 to 60 angstroms (an angstrom is 10 raised to the minus 10 meters, so 0.0000000001 of a meter!! Very small!). Small wavelengths of light have higher energies - so a 1 angstrom wavelength photon (a photon is a "particle" of light) has an energy of about 1 keV. Similarly, longer wavelengths are lower energy, so a 60 angstrom wavelength photon has an energy of about 0.2 keV.
An electron-volt is a unit of energy that is convenient for X-ray astronomers to use - a kiloelectron-volt is 1000 of these units.
More information on the Chandra mission is available at http://chandra.harvard.edu/about/