A new Starlink release contains notable updates to the SCUBA-2 configuration files.

The latest Starlink release - 2014A - has been made public. For details please read the release notes provided at: http://starlink.jach.hawaii.edu/starlink/2014A

As part of this new release we want to highlight one significant update and a couple of new additions to the SCUBA-2 reduction arsenal of config files.

Updates to bright_extended config file

This config file 'dimmconfig_bright_extended.lis' has always been intended for reducing data containing bright extended sources. It has remained untouched for a couple of years now despite advances in our understanding of SCUBA-2 reduction of bright regions. The config file now contains the following parameters/links:

   ^$STARLINK_DIR/share/smurf/dimmconfig.lis

   numiter=-40
   flt.filt_edge_largescale=480
   ast.zero_snr = 3
   ast.zero_snrlo = 2

   ast.skip = 5
   flt.zero_snr = 5
   flt.zero_snrlo = 3

In previous Starlink releases i.e. Hikianalia, the bright_extended configuration file only contained the following:

   numiter = -40
   ast.zero_snr = 5

   flt.filt_edge_largescale = 600

New 'FIX' config file

Two new config parameter files have been added These are intended to be used with one of the existing dimmconfig files. They provide new values for selected parameters aimed at solving a particular problem ("blobs" in the final map, or very slow convergence).

• dimmconfig_fix_blobs.lis 
• These parameters attempt to prevent smooth bright blobs of emission appearing in the final map. It does this by 1) identifying and flagging samples that appear to suffer from ringing a soft-edged Butterworth filter in place of the normal hard-edged filter, and 3) rejecting samples for which the separate sub-arrays see a markedly different common-mode signal.

• dimmconfig_fix_convergence.lis
• The parameters defined by this file attempt to aid the convergence process, and should be used for maps that will not converge within a reasonable number of iterations.