MeerKAT conversion guide

from importlib.metadata import version
import os

try:
    import xradio

    print("XRADIO version", version("xradio"), "already installed.")
except ImportError as e:
    print(e)
    print("Installing XRADIO")

    os.system("pip install xradio")

    import xradio

    print("xradio version", version("xradio"), " installed.")

XRADIO version 1.1.3 already installed.

Download dataset

import toolviper

toolviper.utils.data.download(file="small_meerkat.ms")

[2026-04-20 15:19:05,662]     INFO   toolviper:  Initializing download...
[2026-04-20 15:19:05,662]     INFO   toolviper:  File already exists: /Users/vdesouza/work/xradio/docs/source/measurement_set/guides/small_meerkat.ms

Convert to Processing Set

from xradio.measurement_set import convert_msv2_to_processing_set

ms_file = "small_meerkat.ms"
main_chunksize = {"frequency": 1, "time": 20}  # baseline, polarization
outfile = "small_meerkat.ps.zarr"
convert_msv2_to_processing_set(
    in_file=ms_file,
    out_file=outfile,
    parallel_mode="none",
    persistence_mode='w',
    main_chunksize=main_chunksize,
)

[2026-04-20 15:19:06,067]     INFO   toolviper:  Updated partition scheme used: ['DATA_DESC_ID', 'OBS_MODE', 'OBSERVATION_ID']
[2026-04-20 15:19:06,068]     INFO   toolviper:  Number of partitions: 3
[2026-04-20 15:19:06,069]     INFO   toolviper:  OBSERVATION_ID [0], DDI [0], STATE [1], FIELD [0], SCAN [1], EPHEMERIS [None]
[2026-04-20 15:19:06,236]     INFO   toolviper:  OBSERVATION_ID [0], DDI [0], STATE [2], FIELD [1], SCAN [2, 4, 6], EPHEMERIS [None]
[2026-04-20 15:19:06,370]     INFO   toolviper:  OBSERVATION_ID [0], DDI [0], STATE [3], FIELD [2], SCAN [3, 5], EPHEMERIS [None]

Processing Set

from xradio.measurement_set import open_processing_set

ps_xdt = open_processing_set(ps_store=outfile)
ps_xdt.xr_ps.summary()

	name	scan_intents	shape	execution_block_UID	polarization	scan_name	spw_name	spw_intents	field_name	source_name	line_name	field_coords	session_reference_UID	scheduling_block_UID	project_UID	start_frequency	end_frequency
0	small_meerkat_0	[CALIBRATE_BANDPASS, CALIBRATE_FLUX]	(74, 6, 50, 4)	---	[XX, XY, YX, YY]	[1]	spw_0	[UNSPECIFIED]	[J1939-6342_0]	[J1939-6342_0]	[]	[fk5, 19h39m25.03s, -63d42m45.60s]	---	---	20231115-0022	3.265869e+09	3.276337e+09
1	small_meerkat_1	[CALIBRATE_PHASE, CALIBRATE_AMPLI]	(42, 6, 50, 4)	---	[XX, XY, YX, YY]	[2, 4, 6]	spw_0	[UNSPECIFIED]	[J1619-8418_1]	[J1619-8418_1]	[]	[fk5, 16h19m33.97s, -84d18m19.10s]	---	---	20231115-0022	3.265869e+09	3.276337e+09
2	small_meerkat_2	[TARGET]	(223, 6, 50, 4)	---	[XX, XY, YX, YY]	[3, 5]	spw_0	[UNSPECIFIED]	[J0358-8103_2]	[J0358-8103_2]	[]	[fk5, 3h58m31.50s, -81d03m45.70s]	---	---	20231115-0022	3.265869e+09	3.276337e+09

ms_xdt = ps_xdt["small_meerkat_0"]
ms_xdt

<xarray.DataTree 'small_meerkat_0'>
Group: /small_meerkat_0
│   Dimensions:                     (time: 74, baseline_id: 6, frequency: 50,
│                                    polarization: 4, uvw_label: 3)
│   Coordinates:
│     * time                        (time) float64 592B 1.7e+09 1.7e+09 ... 1.7e+09
│       field_name                  (time) <U32 9kB dask.array<chunksize=(74,), meta=np.ndarray>
│       scan_name                   (time) <U21 6kB dask.array<chunksize=(74,), meta=np.ndarray>
│     * baseline_id                 (baseline_id) int64 48B 0 1 2 3 4 5
│       baseline_antenna1_name      (baseline_id) <U4 96B dask.array<chunksize=(6,), meta=np.ndarray>
│       baseline_antenna2_name      (baseline_id) <U4 96B dask.array<chunksize=(6,), meta=np.ndarray>
│     * frequency                   (frequency) float64 400B 3.266e+09 ... 3.276e+09
│     * polarization                (polarization) <U2 32B 'XX' 'XY' 'YX' 'YY'
│     * uvw_label                   (uvw_label) <U1 12B 'u' 'v' 'w'
│   Data variables:
│       EFFECTIVE_INTEGRATION_TIME  (time, baseline_id) float64 4kB dask.array<chunksize=(20, 6), meta=np.ndarray>
│       FLAG                        (time, baseline_id, frequency, polarization) bool 89kB dask.array<chunksize=(20, 6, 1, 4), meta=np.ndarray>
│       TIME_CENTROID               (time, baseline_id) float64 4kB dask.array<chunksize=(20, 6), meta=np.ndarray>
│       UVW                         (time, baseline_id, uvw_label) float64 11kB dask.array<chunksize=(20, 6, 3), meta=np.ndarray>
│       VISIBILITY                  (time, baseline_id, frequency, polarization) complex64 710kB dask.array<chunksize=(20, 6, 1, 4), meta=np.ndarray>
│       WEIGHT                      (time, baseline_id, frequency, polarization) float32 355kB dask.array<chunksize=(20, 6, 1, 4), meta=np.ndarray>
│   Attributes:
│       creation_date:     2026-04-20T21:19:06.085883+00:00
│       creator:           {'software_name': 'xradio', 'version': '1.1.3'}
│       data_groups:       {'base': {'correlated_data': 'VISIBILITY', 'date': '20...
│       observation_info:  {'observer': ['Kim McAlpine'], 'observing_log': "['una...
│       processor_info:    {'sub_type': '', 'type': ''}
│       schema_version:    4.0.0
│       type:              visibility
├── Group: /small_meerkat_0/antenna_xds
│       Dimensions:                 (antenna_name: 3, cartesian_pos_label: 3,
│                                    receptor_label: 2)
│       Coordinates:
│         * antenna_name            (antenna_name) <U4 48B 'm000' 'm002' 'm063'
│           mount                   (antenna_name) <U6 72B dask.array<chunksize=(3,), meta=np.ndarray>
│           station_name            (antenna_name) <U4 48B dask.array<chunksize=(3,), meta=np.ndarray>
│           telescope_name          (antenna_name) <U7 84B dask.array<chunksize=(3,), meta=np.ndarray>
│         * cartesian_pos_label     (cartesian_pos_label) <U1 12B 'x' 'y' 'z'
│         * receptor_label          (receptor_label) <U5 40B 'pol_0' 'pol_1'
│           polarization_type       (antenna_name, receptor_label) <U1 24B dask.array<chunksize=(3, 2), meta=np.ndarray>
│       Data variables:
│           ANTENNA_DISH_DIAMETER   (antenna_name) float64 24B dask.array<chunksize=(3,), meta=np.ndarray>
│           ANTENNA_POSITION        (antenna_name, cartesian_pos_label) float64 72B dask.array<chunksize=(3, 3), meta=np.ndarray>
│           ANTENNA_RECEPTOR_ANGLE  (antenna_name, receptor_label) float64 48B dask.array<chunksize=(3, 2), meta=np.ndarray>
│       Attributes:
│           overall_telescope_name:  MeerKAT
│           relocatable_antennas:    False
│           type:                    antenna
└── Group: /small_meerkat_0/field_and_source_base_xds
        Dimensions:                       (field_name: 1, sky_dir_label: 2)
        Coordinates:
          * field_name                    (field_name) <U32 128B 'J1939-6342_0'
            source_name                   (field_name) <U32 128B dask.array<chunksize=(1,), meta=np.ndarray>
          * sky_dir_label                 (sky_dir_label) <U3 24B 'ra' 'dec'
        Data variables:
            FIELD_PHASE_CENTER_DIRECTION  (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
            SOURCE_DIRECTION              (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
        Attributes:
            type:     field_and_source

xarray.DataTree

'small_meerkat_0'

• /small_meerkat_0/antenna_xds(13)

  • Dimensions:
    • time: 74
    • baseline_id: 6
    • frequency: 50
    • polarization: 4
    • uvw_label: 3
    • antenna_name: 3
    • cartesian_pos_label: 3
    • receptor_label: 2
  • Coordinates: (7)
    • antenna_name
      (antenna_name)
      <U4
      'm000' 'm002' 'm063'

      array(['m000', 'm002', 'm063'], dtype='<U4')

    • mount
      (antenna_name)
      <U6
      dask.array<chunksize=(3,), meta=np.ndarray>

      Array Chunk Bytes 72 B 72 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type

    • station_name
      (antenna_name)
      <U4
      dask.array<chunksize=(3,), meta=np.ndarray>

      Array Chunk Bytes 48 B 48 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type

    • telescope_name
      (antenna_name)
      <U7
      dask.array<chunksize=(3,), meta=np.ndarray>

      Array Chunk Bytes 84 B 84 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type

    • cartesian_pos_label
      (cartesian_pos_label)
      <U1
      'x' 'y' 'z'

      array(['x', 'y', 'z'], dtype='<U1')

    • receptor_label
      (receptor_label)
      <U5
      'pol_0' 'pol_1'

      array(['pol_0', 'pol_1'], dtype='<U5')

    • polarization_type
      (antenna_name, receptor_label)
      <U1
      dask.array<chunksize=(3, 2), meta=np.ndarray>

      Array Chunk Bytes 24 B 24 B Shape (3, 2) (3, 2) Dask graph 1 chunks in 2 graph layers Data type

  • Data variables: (3)
    • ANTENNA_DISH_DIAMETER
      (antenna_name)
      float64
      dask.array<chunksize=(3,), meta=np.ndarray>

      type :

      quantity

      units :

      m

      Array Chunk Bytes 24 B 24 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • ANTENNA_POSITION
      (antenna_name, cartesian_pos_label)
      float64
      dask.array<chunksize=(3, 3), meta=np.ndarray>

      coordinate_system :

      geocentric

      frame :

      ITRS

      origin_object_name :

      earth

      type :

      location

      units :

      m

      Array Chunk Bytes 72 B 72 B Shape (3, 3) (3, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • ANTENNA_RECEPTOR_ANGLE
      (antenna_name, receptor_label)
      float64
      dask.array<chunksize=(3, 2), meta=np.ndarray>

      type :

      quantity

      units :

      rad

      Array Chunk Bytes 48 B 48 B Shape (3, 2) (3, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • Attributes: (3)

    overall_telescope_name :

    MeerKAT

    relocatable_antennas :

    False

    type :

    antenna

  /small_meerkat_0/field_and_source_base_xds(6)

  • Dimensions:
    • time: 74
    • baseline_id: 6
    • frequency: 50
    • polarization: 4
    • uvw_label: 3
    • field_name: 1
    • sky_dir_label: 2
  • Coordinates: (3)
    • field_name
      (field_name)
      <U32
      'J1939-6342_0'

      array(['J1939-6342_0'], dtype='<U32')

    • source_name
      (field_name)
      <U32
      dask.array<chunksize=(1,), meta=np.ndarray>

      Array Chunk Bytes 128 B 128 B Shape (1,) (1,) Dask graph 1 chunks in 2 graph layers Data type

    • sky_dir_label
      (sky_dir_label)
      <U3
      'ra' 'dec'

      array(['ra', 'dec'], dtype='<U3')

  • Data variables: (2)
    • FIELD_PHASE_CENTER_DIRECTION
      (field_name, sky_dir_label)
      float64
      dask.array<chunksize=(1, 2), meta=np.ndarray>

      frame :

      fk5

      type :

      sky_coord

      units :

      rad

      Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

    • SOURCE_DIRECTION
      (field_name, sky_dir_label)
      float64
      dask.array<chunksize=(1, 2), meta=np.ndarray>

      frame :

      fk5

      type :

      sky_coord

      units :

      rad

      Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • Attributes: (1)

    type :

    field_and_source

• Dimensions:
  • time: 74
  • baseline_id: 6
  • frequency: 50
  • polarization: 4
  • uvw_label: 3
• Coordinates: (9)
  • time
    (time)
    float64
    1.7e+09 1.7e+09 ... 1.7e+09 1.7e+09

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 8.014715757714285, 'dims': []}

    scale :

    utc

    type :

    time

    units :

    s

    array([1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09])

  • field_name
    (time)
    <U32
    dask.array<chunksize=(74,), meta=np.ndarray>

    Array Chunk Bytes 9.25 kiB 9.25 kiB Shape (74,) (74,) Dask graph 1 chunks in 2 graph layers Data type

  • scan_name
    (time)
    <U21
    dask.array<chunksize=(74,), meta=np.ndarray>

    scan_intents :

    ['CALIBRATE_BANDPASS', 'CALIBRATE_FLUX']

    Array Chunk Bytes 6.07 kiB 6.07 kiB Shape (74,) (74,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5

    array([0, 1, 2, 3, 4, 5])

  • baseline_antenna1_name
    (baseline_id)
    <U4
    dask.array<chunksize=(6,), meta=np.ndarray>

    Array Chunk Bytes 96 B 96 B Shape (6,) (6,) Dask graph 1 chunks in 2 graph layers Data type

  • baseline_antenna2_name
    (baseline_id)
    <U4
    dask.array<chunksize=(6,), meta=np.ndarray>

    Array Chunk Bytes 96 B 96 B Shape (6,) (6,) Dask graph 1 chunks in 2 graph layers Data type

  • frequency
    (frequency)
    float64
    3.266e+09 3.266e+09 ... 3.276e+09

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 213623.046875, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 3271209716.796875, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([3.265869e+09, 3.266083e+09, 3.266296e+09, 3.266510e+09, 3.266724e+09,
           3.266937e+09, 3.267151e+09, 3.267365e+09, 3.267578e+09, 3.267792e+09,
           3.268005e+09, 3.268219e+09, 3.268433e+09, 3.268646e+09, 3.268860e+09,
           3.269073e+09, 3.269287e+09, 3.269501e+09, 3.269714e+09, 3.269928e+09,
           3.270142e+09, 3.270355e+09, 3.270569e+09, 3.270782e+09, 3.270996e+09,
           3.271210e+09, 3.271423e+09, 3.271637e+09, 3.271851e+09, 3.272064e+09,
           3.272278e+09, 3.272491e+09, 3.272705e+09, 3.272919e+09, 3.273132e+09,
           3.273346e+09, 3.273560e+09, 3.273773e+09, 3.273987e+09, 3.274200e+09,
           3.274414e+09, 3.274628e+09, 3.274841e+09, 3.275055e+09, 3.275269e+09,
           3.275482e+09, 3.275696e+09, 3.275909e+09, 3.276123e+09, 3.276337e+09])

  • polarization
    (polarization)
    <U2
    'XX' 'XY' 'YX' 'YY'

    array(['XX', 'XY', 'YX', 'YY'], dtype='<U2')

  • uvw_label
    (uvw_label)
    <U1
    'u' 'v' 'w'

    array(['u', 'v', 'w'], dtype='<U1')

• Data variables: (6)
  • EFFECTIVE_INTEGRATION_TIME
    (time, baseline_id)
    float64
    dask.array<chunksize=(20, 6), meta=np.ndarray>

    type :

    quantity

    units :

    s

    Array Chunk Bytes 3.47 kiB 0.94 kiB Shape (74, 6) (20, 6) Dask graph 4 chunks in 2 graph layers Data type float64 numpy.ndarray

  • FLAG
    (time, baseline_id, frequency, polarization)
    bool
    dask.array<chunksize=(20, 6, 1, 4), meta=np.ndarray>

    Array Chunk Bytes 86.72 kiB 480 B Shape (74, 6, 50, 4) (20, 6, 1, 4) Dask graph 200 chunks in 2 graph layers Data type bool numpy.ndarray

  • TIME_CENTROID
    (time, baseline_id)
    float64
    dask.array<chunksize=(20, 6), meta=np.ndarray>

    format :

    unix

    scale :

    utc

    type :

    time

    units :

    s

    Array Chunk Bytes 3.47 kiB 0.94 kiB Shape (74, 6) (20, 6) Dask graph 4 chunks in 2 graph layers Data type float64 numpy.ndarray

  • UVW
    (time, baseline_id, uvw_label)
    float64
    dask.array<chunksize=(20, 6, 3), meta=np.ndarray>

    frame :

    fk5

    type :

    uvw

    units :

    m

    Array Chunk Bytes 10.41 kiB 2.81 kiB Shape (74, 6, 3) (20, 6, 3) Dask graph 4 chunks in 2 graph layers Data type float64 numpy.ndarray

  • VISIBILITY
    (time, baseline_id, frequency, polarization)
    complex64
    dask.array<chunksize=(20, 6, 1, 4), meta=np.ndarray>

    type :

    quanta

    units :

    unkown

    Array Chunk Bytes 693.75 kiB 3.75 kiB Shape (74, 6, 50, 4) (20, 6, 1, 4) Dask graph 200 chunks in 2 graph layers Data type complex64 numpy.ndarray

  • WEIGHT
    (time, baseline_id, frequency, polarization)
    float32
    dask.array<chunksize=(20, 6, 1, 4), meta=np.ndarray>

    Array Chunk Bytes 346.88 kiB 1.88 kiB Shape (74, 6, 50, 4) (20, 6, 1, 4) Dask graph 200 chunks in 2 graph layers Data type float32 numpy.ndarray

• Attributes: (7)

  creation_date :

  2026-04-20T21:19:06.085883+00:00

  creator :

  {'software_name': 'xradio', 'version': '1.1.3'}

  data_groups :

  {'base': {'correlated_data': 'VISIBILITY', 'date': '2026-04-20T21:19:06.104021+00:00', 'description': "Data group derived from the data column 'VISIBILITY' of an MSv2 converted to MSv4", 'field_and_source': 'field_and_source_base_xds', 'flag': 'FLAG', 'uvw': 'UVW', 'weight': 'WEIGHT'}}

  observation_info :

  {'observer': ['Kim McAlpine'], 'observing_log': "['unavailable']", 'project_UID': '20231115-0022', 'release_date': '2023-11-15T11:15:33.834658623'}

  processor_info :

  {'sub_type': '', 'type': ''}

  schema_version :

  4.0.0

  type :

  visibility

ms_xdt.xr_ms.get_field_and_source_xds()

<xarray.DatasetView> Size: 1kB
Dimensions:                       (field_name: 1, sky_dir_label: 2,
                                   baseline_id: 6, frequency: 50,
                                   polarization: 4, time: 74, uvw_label: 3)
Coordinates:
  * field_name                    (field_name) <U32 128B 'J1939-6342_0'
    source_name                   (field_name) <U32 128B dask.array<chunksize=(1,), meta=np.ndarray>
  * sky_dir_label                 (sky_dir_label) <U3 24B 'ra' 'dec'
  * baseline_id                   (baseline_id) int64 48B 0 1 2 3 4 5
  * frequency                     (frequency) float64 400B 3.266e+09 ... 3.27...
  * polarization                  (polarization) <U2 32B 'XX' 'XY' 'YX' 'YY'
  * time                          (time) float64 592B 1.7e+09 ... 1.7e+09
  * uvw_label                     (uvw_label) <U1 12B 'u' 'v' 'w'
Data variables:
    FIELD_PHASE_CENTER_DIRECTION  (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
    SOURCE_DIRECTION              (field_name, sky_dir_label) float64 16B dask.array<chunksize=(1, 2), meta=np.ndarray>
Attributes:
    type:     field_and_source

xarray.DatasetView

• Dimensions:
  • field_name: 1
  • sky_dir_label: 2
  • baseline_id: 6
  • frequency: 50
  • polarization: 4
  • time: 74
  • uvw_label: 3
• Coordinates: (8)
  • field_name
    (field_name)
    <U32
    'J1939-6342_0'

    array(['J1939-6342_0'], dtype='<U32')

  • source_name
    (field_name)
    <U32
    dask.array<chunksize=(1,), meta=np.ndarray>

    Array Chunk Bytes 128 B 128 B Shape (1,) (1,) Dask graph 1 chunks in 2 graph layers Data type

  • sky_dir_label
    (sky_dir_label)
    <U3
    'ra' 'dec'

    array(['ra', 'dec'], dtype='<U3')

  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5

    array([0, 1, 2, 3, 4, 5])

  • frequency
    (frequency)
    float64
    3.266e+09 3.266e+09 ... 3.276e+09

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 213623.046875, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 3271209716.796875, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([3.265869e+09, 3.266083e+09, 3.266296e+09, 3.266510e+09, 3.266724e+09,
           3.266937e+09, 3.267151e+09, 3.267365e+09, 3.267578e+09, 3.267792e+09,
           3.268005e+09, 3.268219e+09, 3.268433e+09, 3.268646e+09, 3.268860e+09,
           3.269073e+09, 3.269287e+09, 3.269501e+09, 3.269714e+09, 3.269928e+09,
           3.270142e+09, 3.270355e+09, 3.270569e+09, 3.270782e+09, 3.270996e+09,
           3.271210e+09, 3.271423e+09, 3.271637e+09, 3.271851e+09, 3.272064e+09,
           3.272278e+09, 3.272491e+09, 3.272705e+09, 3.272919e+09, 3.273132e+09,
           3.273346e+09, 3.273560e+09, 3.273773e+09, 3.273987e+09, 3.274200e+09,
           3.274414e+09, 3.274628e+09, 3.274841e+09, 3.275055e+09, 3.275269e+09,
           3.275482e+09, 3.275696e+09, 3.275909e+09, 3.276123e+09, 3.276337e+09])

  • polarization
    (polarization)
    <U2
    'XX' 'XY' 'YX' 'YY'

    array(['XX', 'XY', 'YX', 'YY'], dtype='<U2')

  • time
    (time)
    float64
    1.7e+09 1.7e+09 ... 1.7e+09 1.7e+09

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 8.014715757714285, 'dims': []}

    scale :

    utc

    type :

    time

    units :

    s

    array([1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09])

  • uvw_label
    (uvw_label)
    <U1
    'u' 'v' 'w'

    array(['u', 'v', 'w'], dtype='<U1')

• Data variables: (2)
  • FIELD_PHASE_CENTER_DIRECTION
    (field_name, sky_dir_label)
    float64
    dask.array<chunksize=(1, 2), meta=np.ndarray>

    frame :

    fk5

    type :

    sky_coord

    units :

    rad

    Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • SOURCE_DIRECTION
    (field_name, sky_dir_label)
    float64
    dask.array<chunksize=(1, 2), meta=np.ndarray>

    frame :

    fk5

    type :

    sky_coord

    units :

    rad

    Array Chunk Bytes 16 B 16 B Shape (1, 2) (1, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

• Attributes: (1)

  type :

  field_and_source

ms_xdt.antenna_xds

<xarray.DataTree 'antenna_xds'>
Group: /small_meerkat_0/antenna_xds
    Dimensions:                 (time: 74, baseline_id: 6, frequency: 50,
                                 polarization: 4, uvw_label: 3, antenna_name: 3,
                                 cartesian_pos_label: 3, receptor_label: 2)
    Coordinates:
      * antenna_name            (antenna_name) <U4 48B 'm000' 'm002' 'm063'
        mount                   (antenna_name) <U6 72B dask.array<chunksize=(3,), meta=np.ndarray>
        station_name            (antenna_name) <U4 48B dask.array<chunksize=(3,), meta=np.ndarray>
        telescope_name          (antenna_name) <U7 84B dask.array<chunksize=(3,), meta=np.ndarray>
      * cartesian_pos_label     (cartesian_pos_label) <U1 12B 'x' 'y' 'z'
      * receptor_label          (receptor_label) <U5 40B 'pol_0' 'pol_1'
        polarization_type       (antenna_name, receptor_label) <U1 24B dask.array<chunksize=(3, 2), meta=np.ndarray>
    Inherited coordinates:
      * baseline_id             (baseline_id) int64 48B 0 1 2 3 4 5
      * frequency               (frequency) float64 400B 3.266e+09 ... 3.276e+09
      * polarization            (polarization) <U2 32B 'XX' 'XY' 'YX' 'YY'
      * time                    (time) float64 592B 1.7e+09 1.7e+09 ... 1.7e+09
      * uvw_label               (uvw_label) <U1 12B 'u' 'v' 'w'
    Data variables:
        ANTENNA_DISH_DIAMETER   (antenna_name) float64 24B dask.array<chunksize=(3,), meta=np.ndarray>
        ANTENNA_POSITION        (antenna_name, cartesian_pos_label) float64 72B dask.array<chunksize=(3, 3), meta=np.ndarray>
        ANTENNA_RECEPTOR_ANGLE  (antenna_name, receptor_label) float64 48B dask.array<chunksize=(3, 2), meta=np.ndarray>
    Attributes:
        overall_telescope_name:  MeerKAT
        relocatable_antennas:    False
        type:                    antenna

xarray.DataTree

'antenna_xds'

• Dimensions:
  • time: 74
  • baseline_id: 6
  • frequency: 50
  • polarization: 4
  • uvw_label: 3
  • antenna_name: 3
  • cartesian_pos_label: 3
  • receptor_label: 2
• Coordinates: (7)
  • antenna_name
    (antenna_name)
    <U4
    'm000' 'm002' 'm063'

    array(['m000', 'm002', 'm063'], dtype='<U4')

  • mount
    (antenna_name)
    <U6
    dask.array<chunksize=(3,), meta=np.ndarray>

    Array Chunk Bytes 72 B 72 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type

  • station_name
    (antenna_name)
    <U4
    dask.array<chunksize=(3,), meta=np.ndarray>

    Array Chunk Bytes 48 B 48 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type

  • telescope_name
    (antenna_name)
    <U7
    dask.array<chunksize=(3,), meta=np.ndarray>

    Array Chunk Bytes 84 B 84 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type

  • cartesian_pos_label
    (cartesian_pos_label)
    <U1
    'x' 'y' 'z'

    array(['x', 'y', 'z'], dtype='<U1')

  • receptor_label
    (receptor_label)
    <U5
    'pol_0' 'pol_1'

    array(['pol_0', 'pol_1'], dtype='<U5')

  • polarization_type
    (antenna_name, receptor_label)
    <U1
    dask.array<chunksize=(3, 2), meta=np.ndarray>

    Array Chunk Bytes 24 B 24 B Shape (3, 2) (3, 2) Dask graph 1 chunks in 2 graph layers Data type

• Inherited coordinates: (5)
  • baseline_id
    (baseline_id)
    int64
    0 1 2 3 4 5

    array([0, 1, 2, 3, 4, 5])

  • frequency
    (frequency)
    float64
    3.266e+09 3.266e+09 ... 3.276e+09

    channel_width :

    {'attrs': {'type': 'quantity', 'units': 'Hz'}, 'data': 213623.046875, 'dims': []}

    observer :

    TOPO

    reference_frequency :

    {'attrs': {'observer': 'TOPO', 'type': 'spectral_coord', 'units': 'Hz'}, 'data': 3271209716.796875, 'dims': []}

    spectral_window_intents :

    ['UNSPECIFIED']

    spectral_window_name :

    spw_0

    type :

    spectral_coord

    units :

    Hz

    array([3.265869e+09, 3.266083e+09, 3.266296e+09, 3.266510e+09, 3.266724e+09,
           3.266937e+09, 3.267151e+09, 3.267365e+09, 3.267578e+09, 3.267792e+09,
           3.268005e+09, 3.268219e+09, 3.268433e+09, 3.268646e+09, 3.268860e+09,
           3.269073e+09, 3.269287e+09, 3.269501e+09, 3.269714e+09, 3.269928e+09,
           3.270142e+09, 3.270355e+09, 3.270569e+09, 3.270782e+09, 3.270996e+09,
           3.271210e+09, 3.271423e+09, 3.271637e+09, 3.271851e+09, 3.272064e+09,
           3.272278e+09, 3.272491e+09, 3.272705e+09, 3.272919e+09, 3.273132e+09,
           3.273346e+09, 3.273560e+09, 3.273773e+09, 3.273987e+09, 3.274200e+09,
           3.274414e+09, 3.274628e+09, 3.274841e+09, 3.275055e+09, 3.275269e+09,
           3.275482e+09, 3.275696e+09, 3.275909e+09, 3.276123e+09, 3.276337e+09])

  • polarization
    (polarization)
    <U2
    'XX' 'XY' 'YX' 'YY'

    array(['XX', 'XY', 'YX', 'YY'], dtype='<U2')

  • time
    (time)
    float64
    1.7e+09 1.7e+09 ... 1.7e+09 1.7e+09

    format :

    unix

    integration_time :

    {'attrs': {'type': 'quantity', 'units': 's'}, 'data': 8.014715757714285, 'dims': []}

    scale :

    utc

    type :

    time

    units :

    s

    array([1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09, 1.700044e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09,
           1.700045e+09, 1.700045e+09, 1.700045e+09, 1.700045e+09])

  • uvw_label
    (uvw_label)
    <U1
    'u' 'v' 'w'

    array(['u', 'v', 'w'], dtype='<U1')

• Data variables: (3)
  • ANTENNA_DISH_DIAMETER
    (antenna_name)
    float64
    dask.array<chunksize=(3,), meta=np.ndarray>

    type :

    quantity

    units :

    m

    Array Chunk Bytes 24 B 24 B Shape (3,) (3,) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • ANTENNA_POSITION
    (antenna_name, cartesian_pos_label)
    float64
    dask.array<chunksize=(3, 3), meta=np.ndarray>

    coordinate_system :

    geocentric

    frame :

    ITRS

    origin_object_name :

    earth

    type :

    location

    units :

    m

    Array Chunk Bytes 72 B 72 B Shape (3, 3) (3, 3) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

  • ANTENNA_RECEPTOR_ANGLE
    (antenna_name, receptor_label)
    float64
    dask.array<chunksize=(3, 2), meta=np.ndarray>

    type :

    quantity

    units :

    rad

    Array Chunk Bytes 48 B 48 B Shape (3, 2) (3, 2) Dask graph 1 chunks in 2 graph layers Data type float64 numpy.ndarray

• Attributes: (3)

  overall_telescope_name :

  MeerKAT

  relocatable_antennas :

  False

  type :

  antenna

ps_xdt.xr_ps.plot_phase_centers()

ps_xdt.xr_ps.plot_antenna_positions_2d()