Accession Number:

ADA136120

Title:

Optical Detection Loss Due to Air-Borne Salts on Diego Garcia

Descriptive Note:

Project rept.

Corporate Author:

MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB

Personal Author(s):

Report Date:

1983-10-28

Pagination or Media Count:

44.0

Abstract:

From 28 April to 8 May 1983, a survey team visited Diego Garcia to determine if the loss of optical transmission due to the deposition of airborne sea salts on its optical components would preclude the installation of a GEODSS site on the southern part of the island. This report describes the objectives, the motivation, the planning, the experimental procedures, the laboratory measurements, the collection and interpretation of the data, the analysis of the data, the expected detection loss, and the selection of a specific location for a GEODSS site. Then, recommendations are offered. Briefly, the results indicated that with the wind from the SE and under typical operating conditions--sky brightness greater than 19.5 magnitudes per square arcsecond and for an operational night of 12 hours--the expected detection loss due to the deposition of air-borne salts on the coverplate of a GEODSS telescope would be approximately one-tenth of a visual magnitude. The maximum loss under atypical conditions would be approximately three-tenths of a magnitude. Since it became apparent during the survey that the detection losses would not be great enough to preclude the installation of a GEODSS site on the southern part of Diego Garcia, an exact location for a site was pin-pointed by the survey team before its departure from the island.

Subject Categories:

  • Atmospheric Physics
  • Optical Detection and Detectors
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE