Test of a differential photometer for extinction gradient correction in full-disk helioseismology

Khatami, M. S.; Fossat, E.

doi:10.1007/bf01580785

Cited by 1 publication

(1 citation statement)

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“…This paper provides a method for determining the impact of terrestrial atmospheric noise and demonstrates a correction for some of these effects. Here we make a distinction between forms of atmospheric noise: random noise due to atmospheric disturbances which requires real time monitoring for correction (McLeod & Isaak 1988;Khatami & Fossat 1994); systematic atmospheric refraction that is differential across the solar disk and considered to be a small effect for all but the very extreme ends of the day; and systematic noise due to the atmospheric gradient across the solar disc, monotonically changing as a function of solar zenith angle. This last systematic effect is commonly referred to as 'differential extinction', differential in space across the solar disc, and is the effect considered here.…”

Section: Introductionmentioning

confidence: 99%

BiSON data preparation: a correction for differential extinction and the weighted averaging of contemporaneous data

Davies

Chaplin

Elsworth

et al. 2014

Monthly Notices of the Royal Astronomical Society

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The Birmingham Solar Oscillations Network (BiSON) has provided high-quality highcadence observations from as far back in time as 1978. These data must be calibrated from the raw observations into radial velocity and the quality of the calibration has a large impact on the signal-to-noise ratio of the final time series. The aim of this work is to maximise the potential science that can be performed with the BiSON data set by optimising the calibration procedure. To achieve better levels of signal-to-noise ratio we perform two key steps in the calibration process: we attempt a correction for terrestrial atmospheric differential extinction; and the resulting improvement in the calibration allows us to perform weighted averaging of contemporaneous data from different BiSON stations. The improvements listed produce significant improvement in the signal-to-noise ratio of the BiSON frequency-power spectrum across all frequency ranges. The reduction of noise in the power spectrum will allow future work to provide greater constraint on changes in the oscillation spectrum with solar activity. In addition, the analysis of the low-frequency region suggests we have achieved a noise level that may allow us to improve estimates of the upper limit of g-mode amplitudes.

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Section: Introductionmentioning

confidence: 99%