orca.calibration.delay_pipeline

Delay calibration pipeline.

This module provides the delay calibration pipeline for OVRO-LWA data. Combines measurement sets across all frequencies to solve for per-antenna delays using Cygnus A as the calibrator.

The pipeline:
  1. Selects optimal MS per frequency based on LST proximity to Cyg A transit.

  2. Concatenates and combines spectral windows with mstransform.

  3. Flags RFI and bad antennas.

  4. Generates Cyg A model and solves for delays.

  5. Produces QA plots showing delay solutions per antenna.

Example

>>> from orca.calibration.delay_pipeline import run_delay_pipeline
>>> run_delay_pipeline('2024-01-15')

Functions

closest_ms_by_lst(ms_list, target_lst_rad)

Find the measurement set closest to target LST.

copytree(src, dst)

Copy directory tree, removing destination if it exists.

run_delay_pipeline(obs_date[, ref_lst, tol_min])

Run delay calibration for all frequencies >= 41 MHz for a given date.

Module Contents

orca.calibration.delay_pipeline.closest_ms_by_lst(ms_list, target_lst_rad)[source]

Find the measurement set closest to target LST.

Parameters:
  • ms_list – List of measurement set paths.

  • target_lst_rad – Target LST in radians.

Returns:

Path to the MS with LST closest to target.

orca.calibration.delay_pipeline.copytree(src, dst)[source]

Copy directory tree, removing destination if it exists.

Parameters:
  • src – Source directory path.

  • dst – Destination directory path.

orca.calibration.delay_pipeline.run_delay_pipeline(obs_date, ref_lst=20.00554072 / 24 * 2 * 3.14159265359, tol_min=1)[source]

Run delay calibration for all frequencies >= 41 MHz for a given date.

This function:
  1. Selects the best MS for each frequency based on proximity to a reference LST.

  2. Copies selected MS files to NVMe.

  3. Concatenates and combines SPWs using mstransform.

  4. Flags RFI using AOFlagger and known bad antennas.

  5. Generates a model (Cyg A only) and applies it.

  6. Runs gaincal to solve for delays.

  7. Outputs:
    • CASA delay calibration table at /lustre/pipeline/calibration/delay/<DATE>/

    • A QA PDF showing per-antenna delays.

  8. Cleans up NVMe temporary files.

Parameters:
  • obs_date (str) – Date in ‘YYYY-MM-DD’ format.

  • ref_lst (float) – Reference LST (in radians). Default is Cyg A transit.

  • tol_min (int) – Reserved for future LST filtering tolerance (minutes).