A TEST OF SELECTED COMPARISON-LINE FITTING TECHNIQUES

• Published in: Publications of the Astronomical Society of the Pacific Vol. 102; no. 656; pp. 1200 - 1207
• Main Authors: GULLIVER, AUSTIN F., HILL, GRAHAM
• Format: Journal Article
• Language: English
• Published: Chicago, IL The Astronomical Society of the Pacific 01.10.1990; University of Chicago Press
• Subjects: Astronomical methods; Astronomy; Calibration; Centroids; Earth, ocean, space; Exact sciences and technology; Fishing lines; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Instruments and Data Analysis; Line spectra; Noise spectra; Observation and data reduction techniques. Computer modeling and simulation; Observatories; Parabolas; Stellar spectra; Wavelengths; Stellar spectrum; Spectrometry; Spectral line profile; Data table; Calibration; Wavelength; Data reduction
• ISSN: 0004-6280; 1538-3873
• DOI: 10.1086/132750

Seven techniques for fitting comparison-line profiles were selected for tests of their relative and absolute accuracies. Relative accuracies were assessed using high signal-to-noise ratio, 2.4 Å mm" 1 Reticon spectra by comparing the rms scatter in the observed vs. calculated wavelengths for 31 lines. For the seven techniques, the rms values ranged from 1.2 mAÅ to 4.9 mÅ. Absolute accuracies were determined by measuring artificial spectra composed of Gaussian and instrumental profiles with and without noise added. Both folded and unfolded instrumental profiles were tested. For the folded profiles, the mean shifts were not significantly different from zero. For the unfolded profiles, the mean shifts determined varied from near zero to as high as 0.6 micron. For each technique, individual comparison lines exhibit internally consistent systematic residuals from a polynomial fit to the wavelength calibration.