Light Balance Update (Measuring VAOD with cosmic rays.) Changes to the method Getting Monte Carlo agreement binning methods track treatment and cuts Upcoming studies

Old Method Plot light balance versus difference in distance (diff. dist.) Find zero slope by varying VAOD in reconstruction.

Method VAOD Stereo observation of a point source gives us 2 equations with 2 unknowns. After some algebra: (“Light Balance”) (Nm = reconstructed source photons under molecular assumption.) (“Optical Path Asymmetry”) Now aerosol measurement involves only one plot. An aerosol scale height SH must be assumed, as usual.

Method Those equations are derived assuming a point source, so some tracks may need to be chopped up.

Monte Carlo This is an “ideal detector” MC.

Monte Carlo … using pass4 to reconstruct - normal detector MC.

Binning Routines The Establishment Another Way: Perhaps simple addition would be less evil. Each tube is a sample of the shower. Ray tracing provides correction for cluster obscuration, spot size, tube gaps, and lateral distribution. If off-axis tubes are corrected inaccurately, nearby (wider) showers will suffer systematically larger errors.

Binning Routines … using pass4/ custom binning routine.

Room for improvement Rebin, chop into sub-segments, weight by photostatistics. Rebin, chop into sub-segments, no weigting.

Upcoming Studies The asymmetric stereo laser configuration. Detector Photometric apathy Hourly measurements of atmospheric attenuation