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suncasa / suncasa-src

Source code of the suncasa——CASA-based Python package for reducing, analyzing, and visualizing solar dynamic spectroscopic imaging data at radio wavelengths
BSD 2-Clause "Simplified" License
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EOVSA: Full Disk Imaging Pipeline Failure Due to Insufficient Unflagged Antennas on 2023 #267

Closed sageyu123 closed 8 months ago

sageyu123 commented 8 months ago

Title: Full Disk Image Generation Failure Due to Insufficient Unflagged Antennas

Description:

Encountered an issue on June, 2023, during the full disk image generation process. The initial self-calibration for bright features (feature_slfcal) encountered a failure, failing to find solutions for any spectral windows (SPWs). This was highlighted by the absence of generated calibration tables in the first self-calibration round, as evidenced by the logs. Subsequently, the pipeline attempted to apply a non-existent calibration table to the visibility (vis) data, causing feature_slfcal to fail and the pipeline to halt.

Error Messages:

 Insufficient unflagged antennas to proceed with this solve.
   (time=2023/06/22/19:10:13.5 field=0 spw=43 chan=0)
 Insufficient unflagged antennas to proceed with this solve.
   (time=2023/06/22/19:05:33.8 field=0 spw=44 chan=0)
 Insufficient unflagged antennas to proceed with this solve.
   (time=2023/06/22/19:08:29.6 field=0 spw=45 chan=0)
 Insufficient unflagged antennas to proceed with this solve.
   (time=2023/06/22/19:08:06.5 field=0 spw=46 chan=0)
 Insufficient unflagged antennas to proceed with this solve.
   (time=2023/06/22/19:04:04.5 field=0 spw=47 chan=0)
2024-02-22 15:18:42 INFO gaincal::::casa Calibration solve statistics per spw:  (expected/attempted/succeeded):
2024-02-22 15:18:42 INFO gaincal::::casa  Spw 0: 1/0/0
2024-02-22 15:18:42 INFO gaincal::::casa  Spw 1: 1/0/0
2024-02-22 15:18:42 INFO gaincal::::casa  Spw 2: 1/1/0
2024-02-22 15:18:42 INFO gaincal::::casa  Spw 3: 1/1/0
2024-02-22 15:18:42 INFO gaincal::::casa  Spw 4: 1/1/0

Multiple instances of "Insufficient unflagged antennas to proceed with this solve" were logged for various SPWs at different times, indicating a significant limitation in the available data for processing. Notably, all attempts across SPWs to solve calibration resulted in failure, with no successful calibrations (0 succeeded out of attempted).

Preliminary Analysis:

The root of the issue appears to stem from an inadequate number of unflagged antennas, particularly exacerbated by the use of a restrictive uvrange>1.5Klambda condition. This limitation severely impacted our ability to compute valid solutions during the feature_slfcal process.

Current Workaround:

As an immediate corrective measure, I've introduced a try/except mechanism within the pipeline code. Should feature_slfcal fail to generate a calibration table due to these conditions, the uvrange constraint is relaxed (set to an empty string), allowing the calibration process to proceed without this limitation.

sageyu123 commented 8 months ago

issue solved.