Robert H. Norton

Computer Measurement of Line Strengths with Application to the Methane Spectrum

Computer-aided measurement of absorption line strengths from high resolution spectra greatly improves the accuracies to which relative line strengths can be determined. This article describes a computer program written for interactive use on a Prime minicomputer to fit simultaneously absorption line positions, strengths, linewidths, and continuum parameters. Application to the methane spectrum indicates that relative line strengths have been measured with accuracies of 2% or better for single isolated absorptions. Line strengths from the Q branches of the ν4 and ν1 + ν4 bands of methane are reported and compared to calculated values given in the 1980 Air Force Geophysical Laboratory (AFGL) Compilation of Molecular Parameters.

Astronomical infrared spectroscopy with a Connes-type interferometer: II-Mars, 2500–3500 cm−1

Mars IR spectra with Connes-type interferometer, noting atmospheric absorption and albedo drop due to surface water

Astronomical Infrared Spectroscopy with a Connes‐Type Interferometer. I. Instrumental

The construction and operation of a Connes‐type Fourier spectrometer are discussed in an astronomical context with a sample of the type of spectra obtained with the system.

Analysis of spectra using correlation functions

We present a novel method for the quantitative analysis of spectra based on the properties of the cross correlation between a real spectrum and either a numerical synthesis or a laboratory simulation. We propose a new goodness-of-fit criterion called the heteromorphic coefficient H that has the property of being zero when a fit is achieved and varying smoothly through zero as the iteration proceeds, providing a powerful tool for automatic or near-automatic analysis. We also show that H can be rendered substantially noise-immune, permitting the analysis of very weak spectra well below the apparent noise level and, as a by-product, providing Doppler shift and radial velocity information with excellent precision. The technique is in regular use in the Atmospheric Trace Molecule Spectroscopy (ATMOS) project and operates in an interactive, real time computing environment with turn-around times of a few seconds or less.