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Updated: Aug 9, 2026

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
Published on: March 22, 2019
The spectrum of NGC 7027 (367-650 nm)
Abstract:
NGC 7027 shows the richest spectrum of any known gaseous nebula. In the region of the spectrum surveyed we have measured lines of ions of H, He, C, N, O, F, Ne, Mg, Si, P, S, Cl, Ar, K, Ca, Mn, and Fe using the new Hamilton Echelle Spectrograph of Lick Observatory with a charge-coupled device (CCD) detector. Since a CCD is a linear detector, whereas photographic emulsions used in the most comprehensive previous studies were not, a considerable enhancement in the accuracy of line intensity measurements is possible.
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