Stakeholder Validation of holog/panel for VLA

[urvashirau]

Stakeholder validation

Contact : Pedro B for VLA operations.
( Initial notes have been copied from this Google Doc

Overview

In December of 2022, we got new holo data with incredible quality, focusing on obtaining the deformation surface map of all dishes. We selected antenna ea27 to have the panel adjustment made by the mechanic team. A new holo was run in March after they had worked on the antennas, and the improvement was outstanding. The surface rms improved from 0.47 mm to 0.31mm. To summarize, we have at least three high-quality recent holo data with AIPS panel correction, which we know for sure that the ea27 results worked substantially.

Planned tests include

• Existing VLA-Pointed holography data, comparing AstroHack with AIPS results (The AIPS corrections, when applied, resulted in significant improvements on the dish surface accuracy).

  • Re-analize the data, now using CASA, and verify if we can recover the same results we got for ea27 using AIPS. Surely, "same" means inside an error range.
  • If ea27 agrees with both CASA and AIPS, look carefully at the surface maps and the dish deformation corrections for all antennas, comparing them with AIPS output.

• Use adjustments derived from AstroHack, from an existing holography run, to make a surface adjustment on an antenna, and evaluate the effect and check improvements.

• New VLA-OTF holography test data, applying AstroHack panel adjustment results on the dish and evaluating. The purpose is to demonstrate end-to-end operations for VLA holography, with AstroHack.

  • In an independent timeline, we plan to run a VLA OTF script to check how the task can handle it. We still do not have an OTF script ready to run VLA data, but as soon as we have it, we can make a short run on a test day and get new OTF data.