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Paper: aTmcam: A Simple Atmospheric Transmission Monitoring Camera For Sub 1 Percent Photometric Precision
Volume: 503, Calibrating Large Surveys and Future Facilities
Page: 25
Authors: Li, T.; DePoy, D. L.; Kessler, R.; Burke, D. L.; Marshall, J. L.; Wise, J.; Rheault, J.-P.; Carona, D. W.; Boada, S.; Prochaska, T.; Allen, R.
Abstract: Traditional color and airmass corrections can typically achieve ∼0.02 mag precision in photometric observing conditions. A major limiting factor is the variability in atmospheric throughput, which changes on timescales of less than a night. We present preliminary results for a system to monitor the throughput of the atmosphere, which should enable photometric precision when coupled to more traditional techniques of less than 1% in photometric conditions. The system, aTmCam, consists of a set of imagers each with a narrow-band filter that monitors the brightness of suitable standard stars. Each narrowband filter is selected to monitor a different wavelength region of the atmospheric transmission, including regions dominated by the precipitable water absorption and aerosol scattering. We have built a prototype system to test the notion that an atmospheric model derived from a few color indices measurements can be an accurate representation of the true atmospheric transmission. We have measured the atmospheric transmission with both narrowband photometric measurements and spectroscopic measurements; we show that the narrowband imaging approach can predict the changes in the throughput of the atmosphere to better than ∼10% across a broad wavelength range, so as to achieve photometric precision less than 0.01 mag.
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