Angstrom Star A*
Unit used to measure the wavelength of X-rays.
A* is equal to approximately 1.0000015x10-10metre
As it is easier to measure the ratio between two X-ray wavelengths than it is to measure the wavelengths themselves, the wavelengths are usually stated as multiples of a standard wavelength.
- 1965 defined by J.A. Bearden to provide a unit approximately equal to the angstrom (10-10 metre or 0.1 nanometre).