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

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

3. 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.

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

5. Monte Carlo
This is an “ideal
detector” MC.

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

7. 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.

8. Binning Routines
… using pass4/ custom
binning routine.

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

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