Magnitudes

Each magnitude is a factor of 2.51 in luminosity. The wavebands are defined by filters, of which a bewildering variety exist; these numbers are approximations to the most commonly used bands.

Band	Central	Width	Flux of Zero
	Wavelength (nm)	(nm)	Magnitude Star ( W m-2nm-1)
			old	(Caltech)	(UKIRT)	(Bessell)
U	365	70	3.0 x 10-11	...	...	4.175 x 10-11
B	440	100	7.2 x 10-11	...	...	6.32 x 10-11
V	550	90	3.9 x 10-11	3.39 x 10-11		3.631 x 10-11
R	700	220	1.6 x 10-11	1.76 x 10-11	...	2.177 x 10-11
I	880	240	8.9 x 10-12	8.33 x 10-12	...	1.126 x 10-11
J	1300	240	2.8 x 10-12	3.21 x 10-12	3.07 x 10-12	3.147 x 10-12
H	1600	240	1.3 x 10-12	1.08 x 10-12	1.12 x 10-12	1.138 x 10-12
K	2100	350	4.6 x 10-13	3.84 x 10-13	4.07 x 10-13	3.961 x 10-13