The following Java applet is an implementation of formulas for the refractive index of humid air, [Ciddor, Appl Opt 35 (1996) 1566 or Birch-Downs, metrologia 31 (1994) 315 or Mathar, J. Opt. A 9 (2007) 470 or Bönsch-Potulski, metrologia 35 (1998) 133 or Colavita-Swain-Akeson-Koresko-Hill, Publ Astr Soc Pac 116 (2004) 876, Tab 1] or pure water vapor [Hill-Lawrence, Infr Phys 26 (1986) 371 or IAPWS Sep 1997]. The formulas are used without regard to their actual ranges of validity and naive use is discouraged.

The conversion of the relative humidity to partial pressures can be done the Greg Carbone's Saturation Vapor Pressure Applet that is listed in Martindale's Applet Center. Some conversions from relative to absolute humidity are also performed by the following applet:

The HTML form below can be used to request a table of refractive indices of humid air as outlined in J Opt A: Pure Appl Opt 9 (2007) 470. Results will be returned to the e-mail address provided, and are only provided at a rate of once per day and when I read my e-mail. The defaults are far away from NTP, and represent approximate seasonal averages of Cerro Paranal.

pressure (Pascal)
temperature (Celsius)
relative humidity (percent)
interval start (micron)
interval end (micron)
e-mail
carbon dioxide (ppmv)
number of samples
The first five and last two fields must be filled with single numbers. Attempts to insert ranges or units or other forms of comments are futile. The first and last points of the wavelength interval must differ.

Note that entering 100 for the water percentage will compute a pure water spectrum with no residual nitrogen etc. To consider saturated water vapor enter values slightly less than 100.

Robotic submissions (submitting the default values) will be ignored.