The solar flux unit (sfu) is a convenient measure of spectral flux density often used in solar radio observations, such as the F10.7 solar activity index: 1 sfu = 104 Jy = 10−22 W⋅m−2⋅Hz−1 = 10−19 erg⋅s−1⋅cm−2⋅Hz−1. See jansky for further information about related units. References External links International solar flux unit Units of measurement in astronomy Radiometry