aTmcam: A Simple Atmospheric Transmission Monitoring Camera For Sub 1% Photometric Precision

Ting Li; D. L. DePoy; R. Kessler; D. L. Burke; J. L. Marshall; J. Wise; J. -P. Rheault; D. W. Carona; S. Boada; T. Prochaska; R. Allen

arXiv · 1302.5738

aTmcam: A Simple Atmospheric Transmission Monitoring Camera For Sub 1% Photometric Precision

Ting Li·D. L. DePoy·R. Kessler·D. L. Burke·J. L. Marshall·J. Wise·J. -P. Rheault·D. W. Carona·S. Boada·T. Prochaska·R. Allen

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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 spec- troscopic 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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Ting Li, D. L. DePoy, R. Kessler, D. L. Burke, J. L. Marshall, J. Wise, J. -P. Rheault, D. W. Carona, S. Boada, T. Prochaska, R. Allen. 2013-02-22. aTmcam: A Simple Atmospheric Transmission Monitoring Camera For Sub 1% Photometric Precision. https://arxiv.org/abs/1302.5738

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