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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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