Web Site Home: Engineering Metrology Toolbox Place of Publication: electronic, NIST web page Key words: air refractive index, Ciddor equation, Edlén equation, index of refraction, interferometry Downs, 'Correction to the updated Edlén equation for the refractive index of air,' Metrologia 31, 315-316 (1994). Downs, 'An updated Edlén equation for the refractive index of air,' Metrologia 30, 155-162 (1993).Ĥ. Edlén, 'The refractive index of air,' Metrologia 2, 71-80 (1966).ģ. Ciddor, 'Refractive index of air: new equations for the visible and near infrared,' Appl.

Finally, we propose a simplified formula that can be used for shop-floor computations of the refractive index when only a hand calculator is available.ġ. In addition, the text gives a complete description of all calculations employed by the web page so that others desiring to reproduce the calculation can do so. The text accompanying the calculations explains our modification of the Edlén water vapor term, provides a tutorial for users of the web page, and reviews and discusses the relative merits of the two equations, the range of validity, and the estimated uncertainty of the calculations. The calculations are performed using either the Ciddor 1 equation or an updated version of the Edlén equation 2,3,4 with a modification of the water vapor term so as to improve accuracy for shop-floor use at temperatures departing substantially from 20 ☌.

Refractive Index of Air Calculator is a web-based tool for calculating the index of refraction of air and wavelength of light in air as a function of various input parameters, using the Ciddor Equation or a modified version of the Edlén Equation.Ībstract: These web pages are intended primarily as a computational tool that can be used to calculate the refractive index of air for a given wavelength of light and given atmospheric conditions (air temperature, pressure, and humidity). 10010 - Short Blocks by Mechanical Comparison 10012 - Long Gage Blocks by Mechanical Comparison 10020 - Length Scale Measurement Procedures at the National Bureau of Standards 10060 - Sieve Calibration 11010 - Thread Wires and Cylinders by Mechanical Comparison 11030 - Balls by Mechanical Comparison 11033 - Ball Diameter by Interferometry 13010 - Optical Flat Calibration by Comparison 13020 - Roundness Standards using the Multi-Position Method 14010 - Angle Blocks by Comparison 14011 - 30 and 45 Degree Angle Blocks by Circle Closure 14020 - Polygon Calibration 14030 - Indexing Tables by Subdivision 14510 - Laser Frequency Calibration 15010 - Roughness Calibrations and Measurements 15030 - Large Step Height Calibrations and Measurements 15030 - Small Step Height Calibrations and Measurements Interferometric Calibration of Sphere Diameter

Index of reflection calculator