Friday, March 7, 2008

Help Miriad Selfcal Tip

IGNORE THE FOLLOWING POST. If Miriad is rescaling to large values during the self-calibration process, this is a sign that something is wrong with your self-calibration and you need to increase the self-calibration interval or need more clean components.

This is a bit off the beaten path, but I'd thought I'd post it anyway. If you're self-calibrating in Miriad, it helps to set the noscale option.

The noscale option prevents Miriad from rescaling the gains during amplitude+phase self-calibrating so that the rms gain is 1.0. If you have a lot of outliers, not setting this option can play havoc with the derived amplitudes. A sign that this may be a problem for your data would be unrealistically large amplitudes (much greater than 1.0) after amplitude+phase self-calibration.

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