clearcal – Re-initializes the calibration for a visibility data set – calibration task

Description

Clearcal reinitializes the calibration columns in a measurement set. Specificially, it will set the MODEL_DATA column (if present) to unity in total intensity and zero in polarization, and it will set the CORRECTED_DATA column to the original (observed) DATA in the DATA column. Use the field and spw parameters to select which data to initialize. If the dataset does not yet have the scratch columns, they will be created (MODEL_DATA only if addmodel=True) and initilized for the whole dataset (field, spw, and intent will be ignored in this case).

Parameters

Title

Parameter	Default	Description
vis	''	Name of input visibility file (MS)
field	''	Select field using field id(s) or field name(s)
spw	''	Select spectral window/channels
intent	''	Select observing intent
addmodel	False	Add MODEL_DATA scratch column

Parameter Explanations

vis

''

Name of input visibility file (MS)

Default: none

Example: vis=’ngc5921.ms’

field

''

Select field using field id(s) or field name(s)

default: ‘’ (all fields)

Use ‘go listobs’ to obtain the list id’s or names. If field string is a non-negative integer, it is assumed a field index, otherwise, it is assumed a field name.

Examples: field=’0~2’; field ids 0,1,2 field=’0,4,5~7’; field ids 0,4,5,6,7 field=’3C286,3C295’; field named 3C286 and 3C295 field = ‘3,4C*’; field id 3, all names starting with 4C

spw

''

Select spectral window/channels

Examples: spw=’0~2,4’; spectral windows 0,1,2,4 (all channels) spw=’<2’; spectral windows less than 2 (i.e. 0,1) spw=’0:5~61’; spw 0, channels 5 to 61, INCLUSIVE spw=’*:5~61’; all spw with channels 5 to 61 spw=’0,10,3:3~45’; spw 0,10 all channels, spw 3, channels 3 to 45. spw=’0~2:2~6’; spw 0,1,2 with channels 2 through 6 in each. spw=’0:0~10;15~60’; spectral window 0 with channels 0-10,15-60. (NOTE ‘;’ to separate channel selections) spw=’0:0~10^2,1:20~30^5’; spw 0, channels 0,2,4,6,8,10, spw 1, channels 20,25,30 type ‘help par.selection’ for more examples.

intent

''

Select observing intent

default: ‘’ (no selection by intent)

Example: intent=’BANDPASS’ (selects data labelled with BANDPASS intent)

addmodel

False

add MODEL_DATA along with CORRECTED_DATA?

Default: False (model will not be added) Options: False|True

If False, it will add/reset only CORRECTED_DATA, model visibilities will then be evaluated when needed.