Effelsberg-Bonn HI
Hyperfine Hydrogen Emissions By Steven J. Grisafi, PhD. The ground state of atomic hydrogen shows an emissions spectral line at 1420.405751786 megahertz, or approximately 21 centimeters. This spectral emissions line is important for measuring recession speeds of galaxies using predictions of the Doppler Shift. Radio astronomers in Germany have published their extensive survey of this … [Read more…]