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Paper: |
The Inhomogeneous Response Across the Solar Disc of Unresolved Doppler Velocity Observations |
Volume: |
416, Solar-Stellar Dynamos as Revealed by Helio- and Asteroseismology: GONG 2008/SOHO 21 |
Page: |
245 |
Authors: |
Broomhall, A.-M.; Chaplin, W. J.; Elsworth, Y.; New, R. |
Abstract: |
Unresolved Doppler velocity measurements are not homogeneous across the solar disc (Brookes et al. 1978). We consider one cause of the inhomogeneity that originates from the BiSON instrumentation itself: the intensity of light observed from a region on the solar disc is dependent on the distance between that region on the image of the solar disc formed in the instrument and the detector. The non-uniform weighting affects the realization of the solar noise and the amplitudes of the solar oscillations observed by a detector. An "offset velocity," which varies with time, is observed in BiSON data and has consequences for the long-term stability of observations. We have attempted to model, in terms of the inhomogeneous weighting, the average observed offset velocity. |
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