Evaluation of r(o) for Propagation Down Through the Atmosphere

Area of Science:

• Optical engineering
• Atmospheric optics
• Astronomy

Background:

• The Fried parameter, r(o), quantifies atmospheric turbulence's impact on optical systems.
• Published data on r(o) for atmospheric propagation is limited.

Purpose of the Study:

• To derive statistical properties of r(o) using existing astronomical seeing data.
• To address the lack of precise r(o) data for atmospheric propagation.

Main Methods:

• Analysis of astronomical seeing data from Hoag and Meinel.
• Statistical derivation of r(o) distributions for observatory sites.

Main Results:

• Two independent datasets show strong agreement for r(o) statistics.
• r(o) exhibits night-to-night variability.
• r(o) follows a log-normal distribution.

Conclusions:

• The log-normal distribution accurately models r(o) variability.
• Median r(o) is 0.114 m for zenith propagation (0.55-microm light).
• r(o) varies by a factor of 1.36 one standard deviation from the median.