SMURF update (June 4th 2010)

We've been making incremental changes to SMURF over the last few weeks so here are a few highlights that have not been covered in other blog entries.

• We've updated the extinction correction parameters that scale from CSO to the relevant filter to use the number just calculated by Jessica Dempsey. You can override these values by setting ext.taurelation.filtname in your map-maker config files to the two coefficients "(a,b)" that you want to use (where filtname is the name of the filter). The defaults are listed in $SMURF_DIR/smurf_extinction.def. We have also added a slight calibration tweak to WVM-derived values to correct them to the CSO scale.
• We have changed the calling interface for the sc2clean command so that it now takes a map-maker config file as input rather than individual command line parameters. This should make it easier to compare what the map-maker is doing to what sc2clean is doing.
• Two new (experimental) models have been added to the iterative map-maker. They are slow and they are experimental:
• SMO will do a boxcar smooth to each time series to calculate the low frequency variation. This might be more reliable than using the FLT model if the only aim is to remove low frequencies.
• PLN will fit and remove a plane from each time slice.
• There have been some enhancements to the step finding code so that it not only finds the steps more accurately but can also find correlated steps that occur at the same place for all bolometers.
• The map-maker has a new ast.zero_notlast parameter that can be set to true when used in conjunction with ast.zero_lowhits to disable the final iteration from being forced to zero.

All these changes are available in the 64-bit linux stardev rsync location and also in the most recent Mac Snow Leopard tar ball.