Results for the March 2006 test using ATs and FINITO

These observations, performed on March 31st, used FINITO to successfully stabilize the fringes. The results are shown for the first and last fringe track file. For each of them, we first show the group delay computed by the EWS package, and below visibility results from both the EWS and MIA packages,

The offset between the group delay and LOCALOPD when using FINITO causes the white light interferograms (shown in the MIA interactive analysis window) to be attenuated and even totally suppressed during FINITO tracking. The offset is presumably an artefact and should be set to zero. The visibility amplitude as a function of wavelength is not greatly affected by this offset due to the small bandwidth afforded by the high spectral resolution of the GRISM.

This analysis does not yet make use of the possibility to stack coherently the interferograms during the FINITO fringe track. Only then will the advantage of fringe tracking become most apparent for targets with low visibilities.