The Observation class

The Observation class is used to handle the attributes and parameters of a measurement set.

class rapthor.lib.observation.Observation(ms_filename, starttime=None, endtime=None)

The Observation object contains various MS-related parameters

Parameters:

ms_filenamestr

Filename of the MS file

starttimefloat, optional

The start time of the observation (in MJD seconds). If None, the start time is the start of the MS file

endtimefloat, optional

The end time of the observation (in MJD seconds). If None, the end time is the end of the MS file

convert_mjd(mjd_sec)

Converts MJD to casacore MVTime

Parameters:

mjd_secfloat

MJD time in seconds

Returns:

mvtimestr

Casacore MVTime string

copy()

Returns a copy of the observation

get_bandwidth_smearing_factor(freq, delta_freq, delta_theta, resolution)

Returns peak flux density reduction factor due to bandwidth smearing

Parameters:

freqfloat

Frequency at which averaging will be done

delta_freqfloat

Bandwidth over which averaging will be done

delta_thetafloat

Distance from phase center

resolutionfloat

Resolution of restoring beam

Returns:

reduction_facgtorfloat

Ratio of pre-to-post averaging peak flux density

get_nearest_frequstep(freqstep)

Gets the nearest frequstep

Parameters:

freqstepint

Target frequency step

Returns:

optimum_stepint

Optimum frequency step nearest to target step

get_target_bandwidth(freq, delta_theta, resolution, reduction_factor)

Returns the bandwidth for given peak flux density reduction factor

Parameters:

freqfloat

Frequency at which averaging will be done

delta_thetafloat

Distance from phase center

resolutionfloat

Resolution of restoring beam

reduction_factorfloat

Ratio of pre-to-post averaging peak flux density

Returns:

delta_freqfloat

Bandwidth over which averaging will be done

get_target_timewidth(delta_theta, resolution, reduction_factor)

Returns the time width for given peak flux density reduction factor

Parameters:

delta_thetafloat

Distance from phase center

resolutionfloat

Resolution of restoring beam

reduction_factorfloat

Ratio of pre-to-post averaging peak flux density

Returns:

delta_timefloat

Time width in seconds for target reduction_factor

scan_ms()

Scans input MS and stores info

set_calibration_parameters(parset, ndir, nobs)

Sets the calibration parameters

Parameters:

parsetdict

Parset with processing parameters

ndirint

Number of calibration directions/patches

nobsint

Number of observations in total

set_imaging_parameters(sector_name, cellsize_arcsec, max_peak_smearing, width_ra, width_dec, solve_fast_timestep, solve_slow_freqstep, use_screens)

Sets the imaging parameters

Parameters:

sector_namestr

Name of sector for which predict is to be done

cellsize_arcsecfloat

Pixel size in arcsec for imaging

width_rafloat

Width in RA of image in degrees

width_decfloat

Width in Dec of image in degrees

solve_fast_timestepfloat

Solution interval in sec for fast solve

solve_slow_freqstepfloat

Solution interval in Hz for slow solve

use_screensbool

If True, use setup appropriate for screens

set_prediction_parameters(sector_name, patch_names, scratch_dir)

Sets the prediction parameters

Parameters:

sector_namestr

Name of sector for which predict is to be done

patch_nameslist

List of patch names to predict

scratch_dirstr

Scratch directory path