orca.calibration.delay_pipeline
===============================

.. py:module:: orca.calibration.delay_pipeline

.. autoapi-nested-parse::

   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.

   .. admonition:: Example

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



Functions
---------

.. autoapisummary::

   orca.calibration.delay_pipeline.closest_ms_by_lst
   orca.calibration.delay_pipeline.copytree
   orca.calibration.delay_pipeline.run_delay_pipeline


Module Contents
---------------

.. py:function:: closest_ms_by_lst(ms_list, target_lst_rad)

   Find the measurement set closest to target LST.

   :param ms_list: List of measurement set paths.
   :param target_lst_rad: Target LST in radians.

   :returns: Path to the MS with LST closest to target.


.. py:function:: copytree(src, dst)

   Copy directory tree, removing destination if it exists.

   :param src: Source directory path.
   :param dst: Destination directory path.


.. py:function:: run_delay_pipeline(obs_date, ref_lst=20.00554072 / 24 * 2 * 3.14159265359, tol_min=1)

   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.

   :param obs_date: Date in 'YYYY-MM-DD' format.
   :type obs_date: str
   :param ref_lst: Reference LST (in radians). Default is Cyg A transit.
   :type ref_lst: float
   :param tol_min: Reserved for future LST filtering tolerance (minutes).
   :type tol_min: int