Jansky

The jansky (symbol Jy) is a non-SI unit of spectral flux density, or spectral irradiance, equivalent to 10⁻²⁶watts per square metre per hertz.

The flux density or monochromatic flux, , of a source is the integral of the spectral radiance, , over the source solid angle:

The unit is named after pioneering US radio astronomer Karl Guthe Jansky, and is defined as:

(SI) (cgs)

Since the jansky is obtained by integrating over the whole source solid angle, it is most simply used to describe point sources; for example, the Third Cambridge Catalogue of Radio Sources (3C) reports results in Jy.

Jansky (crater)

Jansky is a lunar impact crater that lies along the eastern limb of the Moon. It lies due east of the larger walled plain Neper, along the southern edge of the Mare Marginis. Due to its location, this crater is viewed from the side from Earth, limiting the amount of detail that can be observed. The visibility is also affected by libration, which can completely conceal this formation from view.

This is a worn crater with an eroded rim. The southern part of the rim in particular is disrupted and irregular in form, with a pair of small craters along the inner wall. The remainder of the rim is roughly circular. The interior floor is relatively featureless, except for a few tiny craterlets.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Jansky.

References

Jansky (surname)

Jánský, less commonly accented Janský, is a Czech-language surname.

Some notable people with the surname include:

See also