Convert vacuum wavelengths to air wavelengths
vacuum wavelength, in Angstroms, scalar or vector
Corrects for the index of refraction of air under standard conditions. Wavelength values below 2000 A will not be altered. Method from Ciddor (1996). Accurate to about 10 m/s.
air wavelength, in Angstroms, scalar -r vector
Written by D. Lindler 1982
R adaptation by Arnab Chakraborty June 2013
Ciddor, P. E. 1996, Refractive index of air: New equations for the visible and near infrared, Applied Optics, 35, 1566. http://adsabs.harvard.edu/abs/1996ApOpt..35.1566C
vactoair(2000.000) # yields air wavelength 1999.353 Angstroms