Further Analysis of the Mount Wilson Sunset Observations

Abstract

The calculated time of sunset in Hilton (2014a) to analyze the sunset times observed by Rarogiewicz (1994) were computed using an early version of SLAC 2.0. A second analysis is made here using a significantly improved refraction algorithm. The change in the calculated times of sunset do not change significantly from those of the preliminary analysis. Rarogiewicz (1994) also contains previously un-analyzed observations of the time of contact of the lower limb and the center of the Sun with the horizon. These lower limb and center contact observations are found to agree generally with the refraction at large zenith distances calculated using the modified standard atmosphere model rather than the observed times of sunset. The difference maybe explained by the combination of: a thin (few hundred meter thick) atmospheric boundary layer, irradiation, and the rapid change in illumination that occurs at sunset. A more detailed analysis of the problem of the Channel Islands shows, conclusively, that they cannot have any affect on the observations.

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Document Details

Document Type
Technical Report
Publication Date
Nov 17, 2016
Accession Number
AD1097511

Entities

People

  • James L. Hilton

Organizations

  • United States Naval Observatory

Tags

Communities of Interest

  • Sensors

DTIC Thesaurus Topics

  • Accuracy
  • Algorithms
  • Altitude
  • Atmospheric Refraction
  • Atmospheric Temperature
  • Barometric Pressure
  • Boundary Layer
  • Detectors
  • Humidity
  • Inversion
  • Lapse Rate
  • Measurement
  • Meteorology
  • Observation
  • Observers
  • Refraction
  • Water Vapor

Fields of Study

  • Physics

Readers

  • Geodesy
  • Public Financial Management and Budgeting
  • Solar Physics