• Valerie Illingworth
Part of the Macmillan Dictionary Series book series (DICTS)


jansky. Symbol: Jy. The unit of *flux density adopted by the IAU in 1973 and used throughout the spectral range, especially for radio and far-infrared measurements. One jansky is equal to 10−26 watts per metre squared per hertz. It is possible to calculate the equivalent flux density, F(v), in jansky from a value of *mag- nitude at the effective wavelength, λeff, appropriate to a particular optical or infrared filter (see table). For example, an R magnitude of 3.2 corresponds to a flux density at 0.7 μ of
$${\text{2770x1}}{{\text{0}}^{{\text{ - 0}}{\text{.4x3}}{\text{.2}}}}{\text{Jy}}$$
i.e. 145 Jy. (The table gives the flux level for 0.0 magnitude.)


Radiation Belt Lower Cloud High Cloud Julian Date Minor Planet 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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© Laurence Urdang Associates Ltd 1979

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  • Valerie Illingworth

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