fixplanets

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0.1.26 fixplanets

Requires:

Synopsis
Changes FIELD and SOURCE table entries based on user-provided direction or POINTING table, optionally fixes the UVW coordinates

Description

This task’s main purpose is to correct observations which were performed with correct pointing and correlation but for which incorrect direction information was entered in the FIELD and SOURCE table of the MS. If you actually want to change the phase center of the visibilties in an MS, you should use task fixvis.

Input Parameters vis – Name of the input visibility set

field – field selection string

fixuvw – recalc uvw coordinates? (default: False)

direction – if set, don’t use pointing table but set direction to this value. The direction can either be given explicitly or as the path to a JPL Horizons ephemeris (for an example of the format, see directory data/ephemerides/JPL-Horizons/). Alternatively, the ephemeris table can also be provided as mime format file, i.e. a saved email as obtained via the commands (for example): import recipes.ephemerides.request as jplreq jplreq.request_from_JPL(objnam=’Mars’,startdate=’2012-01-01’,enddate=’2013-12-31’, date_incr=’0.1 d’, get_axis_orientation=False, get_axis_ang_orientation=True, get_sub_long=True, use_apparent=False, get_sep=False, return_address=’YOUR_EMAIL_ADDESS’, mailserver=’YOUR_MAIL_SERVER_ADDRESS’) Note: some mail clients may not save the JPL mail properly. Confirmed to work is Thunderbird.

default= ” (use pointing table)

example: ’J2000 19h30m00 -40d00m00’

refant – if using pointing table information, use it from this antenna default: 0 (antenna id 0) examples: ’DV06’ (antenna with name DV06) 3 (antenna id 3) reftime – if using pointing table information, use it from this timestamp default: ’first’ examples: ’median’ will use the median timestamp for the given field using only the unflagged maintable rows ’2012/07/11/08:41:32’ will use the given timestamp (must be within the observaton time)

Arguments


Inputs
vis	Name of the input visibility set.
	allowed:	string
	Default:
field	Fields to operate on. Blank = all.
	allowed:	any
	Default:	variant ””
fixuvw	recalc uvw?
	allowed:	bool
	Default:	False
direction	if set, don’t use pointing table but set direction to this value
	allowed:	any
	Default:	variant
refant	if using pointing table information, use it from this antenna
	allowed:	any
	Default:	variant 0
reftime	if using pointing table information, use it from this timestamp (’first’, ’median’, or YYYY/MM/DD/hh:mm:ss)
	allowed:	string
	Default:	first

Example

    Examples:

    fixplanets(’uid___A002_X1c6e54_X223.ms’, ’Titan’, True)
          will look up the pointing direction from antenna 0 for field ’Titan’ in
          the POINTING table based on the first timestamp in the main table rows for
          this field, enter this direction in the FIELD and SOURCE tables, and then
          recalculate the UVW coordinates for this field.

    fixplanets(’uid___A002_X1c6e54_X223.ms’, ’Titan’, True, ’Titan_55438-56292dUTC.tab’)
          will attach the ephemeris table ’Titan_55438-56292dUTC.tab’ to field ’Titan’
          and then recalculate the UVW coordinates for this field.

    fixplanets(’uid___A002_X1c6e54_X223.ms’, ’Titan’, False, ’J2000 12h30m15 -02d12m00’)
          will set the directions for field ’Titan’ in the FIELD and SOURCE table to the
          given direction and not recalculate the UVW coordinates.
          (This can be useful for several purposes, among them preparing a concatenation
          of datasets. Only fields with the same direction will be recognised as identical.
          fixplanets can then be run again after the concatenation using parameters as in
          the first example above.)

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