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2025A semester sub-arrays and configuration

2025A semester sub-arrays and configuration

Owned by Andrew Williams
Last updated: Mar 20, 2025
5 min read

Starting with the 2025A semester, MWA will be running with 32 receivers, each capable of digitising 8 tiles simultaneously, for a maximum of 256 tiles.

The SHAO receivers handling the tiles in the ‘Phase II compact’ configuration (core tiles, plus hexes, see below), can be configured to run in oversampling mode, to eliminate the artefacts at coarse channel boundaries, but this has some caveats:

  • When the correlator is running in ‘oversampling’ mode, all of the RRI receivers must be disabled, because the correlator can’t handle a mix of oversampled data (from SHAO and/or NI receivers) and critically sampled data (from RRI receivers). That means at most 128 tiles can be used - the tiles in the ‘Phase II compact’ configuration below.

  • Changing between ‘oversampling’ and ‘critically sampled’ mode is currently manual, and labour intensive, and will happen during the 2025A semester on a weekly basis, at best, with a cadence depending on the balance between oversampling and non-oversampling time requested for that week/month.

  • In 2025A, the NI receivers will still be connected to very long-baseline solar tiles (the LBF and LBG groups), so will not be included in the compact configuration with the SHAO receivers.

For normal (critically sampled) observations, the correlator will run in 256T mode all the time, with all 32 receivers active. Each observation can be scheduled with whatever subarray is desired for that target. The standard D0006 morning and evening calibrator blocks will be scheduled as full array (256T) observations, so calibrations can be applied to any subarray taken.

The subarrays offered in 2025A are:

  • Phase II compact - the 56 Phase I core tiles, plus the 72 Phase II hex tiles, for 128 tiles in total. Can be run in the critically sampled mode, or with oversampling.

  • Phase II extended - the 72 Phase I extended tiles, plus the 56 Phase II Solar tiles, for 128 tiles in total. (Critically sampled mode only)

  • Phase I plus hexes - the 128 tiles from Phase I, plus the 72 Phase II hex tiles, for 200 tiles in total. (Critically sampled mode only)

  • Phase I plus Solar - the 128 tiles from Phase I, plus the 56 Phase II solar powered tiles, for 184 tiles in total. (Critically sampled mode only)

  • Full Array - all 256 tiles. (Critically sampled mode only)

Use this online tool to calculate total data volumes for a given observing time and correlator mode, or for VCS. Note that data volumes for oversampled VCS data are larger than critically sampled VCS, by a factor or 32/25, but oversampled correlated visibilities are the same size in as critically sampled observations. https://ws.mwatelescope.org/data/volcalc

See the table below for details on receiver groupings and which tiles are in the different subarrays.

When reducing data, the reduction pipeline will number tiles and inputs from 0-N in the order defined in the metafits file for that observation (the table in the primary HDU) - see here for documentation.

Note that this order will always be in increasing order of Tile ID, as defined in the table below (and the metafits file).

A spreadsheet with full coordinates of tiles in all these configurations can be found here:

 

Tile Name

Tile IDs

Name

Type

Region

Can oversample?

Phase II compact

(128T)

Phase II extended

(128T)

Phase I plus hexes

(200T)

Phase I plus Solar Powered

(184T)

Full array

(256T)

Tile Name

Tile IDs

Name

Type

Region

Can oversample?

Phase II compact

(128T)

Phase II extended

(128T)

Phase I plus hexes

(200T)

Phase I plus Solar Powered

(184T)

Full array

(256T)

Tile011-18

11-18

TBD (pad 1)

SHAO

Phase I core

Yes

Y

 

Y

Y

Y

Tile021-26, 47, 28

21-26,47,28

TBD (pad 8)

SHAO

Phase I core

Yes

Y

 

Y

Y

Y

Tile031-38

31-38

TBD (pad 2)

SHAO

Phase I core

Yes

Y

 

Y

Y

Y

Tile041-46, 27, 48

41-46,27,48

TBD (pad 2)

SHAO

Phase I core

Yes

Y

 

Y

Y

Y

Tile051-58

51-58

rec05

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile061-68

61-68

TBD (pad 1)

SHAO

Phase I core

Yes

Y

 

Y

Y

Y

Tile071-78

71-78

rec07

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile081-88

81-88

TBD (pad 8)

SHAO

Phase I core

Yes

Y

 

Y

Y

Y

Tile091-98

91-98

TBD (pad 9)

SHAO

Phase I core

Yes

Y

 

Y

Y

Y

Tile101-108

101-108

rec10

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile111-118

111-118

rec11

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile121-128

121-128

rec12

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile131-138

131-138

rec02

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile141-148

141-148

rec06

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile151-158

151-158

rec15

RRI

Phase I extended

 

 

Y

Y

Y

Y

Tile161-168

161-168

rec04

RRI

Phase I extended

 

 

Y

Y

Y

Y

HexE01-08

1001-1008

TBD (pad 9)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexE09-16

1009-1016

rec19 (pad 3)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexE17-24

1017-1024

rec20 (pad 3)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexE25-32

1025-1032

TBD (pad 4)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexE32-E36, HexS01-S04

1033-1040

TBD (pad 4)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexS05-12

1041-1048

TBD (pad 5)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexS13-20

1049-1056

TBD (pad 5)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexS21-S28

1057-1064

TBD (pad 6)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

HexS29-S36

1065-1072

TBD (pad 6)

SHAO

Phase II Hexes

Yes

Y

 

Y

 

Y

LBFA1-A8

2001-2008

rec01

RRI

Phase II Solar

 

 

Y

 

Y

Y

LBB1-B8

2009-2016

rec08

RRI

Phase II Solar

 

 

Y

 

Y

Y

LBC1-C8

2017-2024

rec14

RRI

Phase II Solar

 

 

Y

 

Y

Y

LBD1-D8

2025-2032

rec09

RRI

Phase II Solar

 

 

Y

 

Y

Y

LBE1-E8

2033-2040

rec13

RRI

Phase II Solar

 

 

Y

 

Y

Y

LBF1-F8

2041-2048

rec18

NI

Phase II Solar

(YES)**

 

Y

 

Y

Y

LBG1-G8

2049-2056

rec17

NI

Phase II Solar

(YES)**

 

Y

 

Y

Y

 

** Capable of oversampling, but will not be used that way in 2025A, because they currently still connected to very long-baseline tiles.

tiles-p2c.png
tiles-p2e.png
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