Ground based measurement of ozone using stellar spectra

Abstract

The use of stars as a radiation source for ground-based ozone remote-sensing instruments is explored and an automated prototype instrument that measures absorption due to atmospheric ozone in stellar spectra has been designed, implemented and tested. This work represents the proof-of-concept development of a low-cost, low dispersion slitless imaging spectrometer that measures Chappuis-band absorption in stellar spectra. The work presented here progresses from the initial concept to a functional calibrated prototype that is capable of nightly automated observations of visible-band spectra from mid-magnitude stars. The design and calibration of the prototype and subsequent data collection and analysis are presented. A slitless imaging spectrometer has been developed and integrated with a commercial self-pointing telescope and an astronomical imager. A relative intensity calibration and the development of a dynamic wavelength calibration scheme, necessitated by the slitless nature of the instrument, is presented. The calibrated prototype has been used to collect several data sets of stellar spectra, and it is shown that the instrument can detect Chappuis absorption in stellar spectra. Several issues with both the concept and design that must be addressed in further development of the prototype are identified.