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(unit of measurement of spectral flux density)

The Jansky (Jy) is a CGS (non-SI) unit of spectral Flux density equivalent to 10-26 Watts per square meter per Hertz. It is often used in Radio astronomy to describe the brightness of sources at particular Frequencies. Examples:

  • 4 million - Sun at 10 GHz
  • 1 million - Milky Way at 20 MHz
  • 2,000 - Milky Way at 10 GHz
  • 1,000 - Quiet Sun at 20 MHz

Some common variants are Millijansky (mJy, also referred to as m.f.u. for Milli Flux Unit), and Megajansky (MJy).


Referenced by:
AB System
1 Jansky Empty Field Survey (1 Jy)