U
(U band)
(photometric filter for ultraviolet light)
The letter U (or U band) is commonly used to indicate a passband
located in the ultraviolet range (U for ultraviolet), typically
for one located not far from the visible light range. The
letter is also often used for a filter for the band (or more
explicitly, a U filter), and to indicate a magnitude of a signal
observed through such a filter, e.g., citing "U = 1.5".
In the conventional UBV photometric system and its offshoots,
the U band is centered around wavelength 365 nm, with a width
of 66 nm (full width at half maximum). Other systems may have different specifications,
in some cases, similar.
(EMR,ultraviolet,band,photometry)
Further reading:
https://en.wikipedia.org/wiki/Photometric_system
https://en.wikipedia.org/wiki/UBV_photometric_system
https://ui.adsabs.harvard.edu/abs/1953ApJ...117..313J/abstract
https://www.schoolsobservatory.org/learn/tech/instruments/filters
https://sites.astro.caltech.edu/~george/ay122/Bessel2005ARAA43p293.pdf
WaveL | Freq | Photon Energy | | |
365nm | 821THz | 3.4eV | | U |
|
Referenced by pages:
color index
color-color diagram (CCD)
passband
SkyMapper Southern Survey (SMSS)
Strömgren photometric system
UBV photometric system
UVJ diagram
Vega
Index