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Spectral resolution

The spectral resolution obtained using TAURUS is equal to the free spectral range of the etalon divided by its finesse. The free spectral range is a function of the etalon gap and the wavelength, and is summarised for the etalons currently available in Table gif.

The etalon finesse depends on a number of factors, including the surface quality and reflectivity of the etalon plates, and the accuracy with which they can be maintained in alignment. Values of the finesse measured on the telescope are typically about 20, and the spectral resolution obtained with this finesse for each of the TAURUS is etalons is given in Table gif.

Tue Aug 15 16:42:46 BST 1995