If you need an accessible version of this item please contact JSTOR User Support

A Method for Calculating Moonlight Illuminance at the Earth's Surface

R. H. Austin, B. F. Phillips and D. J. Webb
Journal of Applied Ecology
Vol. 13, No. 3 (Dec., 1976), pp. 741-748
DOI: 10.2307/2402251
Stable URL: http://www.jstor.org/stable/2402251
Page Count: 8
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
A Method for Calculating Moonlight Illuminance at the Earth's Surface
Preview not available

Abstract

(1) A method of calculating the illuminance of moonlight reaching any location on the earth's surface, on any night of any year, is described. (2) Factors examined are whether the amount of sunlight is negligible, whether the moon is above the horizon, the changing distance of the moon, elongation or phase effect, atmospheric extinction, the angle of incidence of moonlight, and cloud cover. (3) A computer is used to calculate the variation in the illuminance due to each of the above factors, except the variation due to cloud cover, which is handled manually. The calculated variations are then used in the program to modify an arbitrary value of 100, chosen to represent the moonlight illuminance derived from the full moon, at the zenith, at a distance corresponding to the mean equatorial parallax. This is equal to 0.215 lux and relative moonlight illuminances can be converted to light values using this relationship. (4) Results of the use of the method are compared with the published results where measurements were made with a visual photometer. The comparison showed that the method is sufficiently accurate to be of value in ecological studies of marine and terrestrial nocturnal animals.

Page Thumbnails

  • Thumbnail: Page 
741
    741
  • Thumbnail: Page 
742
    742
  • Thumbnail: Page 
743
    743
  • Thumbnail: Page 
744
    744
  • Thumbnail: Page 
745
    745
  • Thumbnail: Page 
746
    746
  • Thumbnail: Page 
747
    747
  • Thumbnail: Page 
748
    748