24.1 Change summary for Version 4.6

Version 4.6 is a critical release with one major bug correction, a few smaller ones, and large number of improvements, such as choice of Color model for messages.

It now includes full support for Mosaics in the Gueth method, including self-calibration and UV_RESTORE capability, as well as PIPELINE treatment. Partial support for the Sault mode (adapted to larger mosaics) is available.

It also supports hybrid mosaics, obtained by combining data from arrays with different primary beams (but no hybrid baselines).

• MAJOR: In Version 4.5, a bug was introduced in the basic phase shifting routine for UV data. As a result, Mosaics could only be properly imaged if the UV data had a common phase center for all fields, but no error message was issued otherwise. Furthermore, since the basic shifting routine was the problem, there was no way to set a common phase center with IMAGER.

  The bug escaped detection in the test suite because all test mosaics were already in the proper mode.

• Command UV_CIRCLE could crash if issues after command UV_CONTINUUM. This was due to a lack of update of the min-max of the baseline lengths. A work-around was to use HEADER UV/EXTREMA after UV_CONTINUUM.
• Command UV_MERGE/CONTINUUM would occasionally ignore the specified reference frequency, or even crash due to initialized value.

It also includes a number of added and improved commands:

• PIPELINE and SELFCAL improvements, such as automatic choice of best self-calibration solution.
• MASK THRESHOLD with REGION keyword now order labelled regions by decreasing flux, providing an easier selection of regions of interest.
• Added command UV_SUBTRACT that allows a visibility based continuum subtraction
• Command UV_REWEIGHT returns weight factor as SIC variable UV_WEIGHT_SCALE. UV_REWEIGHTROBUST allows to set the weight using the MAP_ROBUST parameter.
• Better error messages in UV_FIT
• Improved noise estimate in Array Simulator.
• Improved COLOR command for bitmaps.
• Contours are now disabled by default in command SHOW. Option SHOW /CONTOUR added.
• Use option READ /NOCACHE to force reading again data.