Accepted for publication in ApJ 2002.
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Abstract. We present a measurement of the absolute surface brightness of the
zodiacal light (3900-5100Å) toward a fixed extragalactic target at
high ecliptic latitude based on moderate resolution (~ 1.3Å per
pixel) spectrophotometry obtained with the du Pont 2.5m telescope at
Las Campanas Observatory in Chile. This measurement and
contemporaneous Hubble Space Telescope data from WFPC2 and FOS
comprise a coordinated program to measure the mean flux of the diffuse
extragalactic background light (EBL). The zodiacal light at optical
wavelengths results from scattering by interplanetary dust, so that
the zodiacal light flux toward any extragalactic target varies
seasonally with the position of the Earth. This measurement of
zodiacal light is therefore relevant to the specific observations
(date and target field) under discussion. To obtain this result, we
have developed a technique that uses the strength of the zodiacal
Fraunhofer lines to identify the absolute flux of the zodiacal light
in the multiple-component night sky spectrum. Statistical
uncertainties in the result are 0.6% (1
). However, the
dominant source of uncertainty is systematic errors, which we estimate
to be 1.1% (1). We discuss the contributions included in
this estimate explicitly. The systematic errors in this result
contribute 25% in quadrature to the final error in our coordinated
EBL measurement, which is presented in the first paper of this series.
Keywords: Diffuse radiation - cosmology: observations - techniques: spectroscopic - interplanetary medium
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