2023/09/19 DRR Pupil Polarimetry

This contains the data and processing results from the proposed DRR measurement by Jaren Ashcraft.

The calibration files are in `master_cals/`. The dark frames are common for all data and the flats are organized by filter. The flat files were created from the mean combination of all pupil images in that filter, effectively averaging all polarization states creating a good polarization flat.

The dark-subtracted, flat-fielded, recentered, median-collapsed data are in the `collapsed/` folder. In the `diff` folder each file contains a data cube of exactly 2 frames. The first is the sum of `cam1 + cam2` for each simultaneous observation. The second frame is the difference `cam1 - cam2`.

The data was processed using the vampires_dpp (branch `v2.0`). The configuration file used for processing is provided `20230919_drr_pupil.toml`. For each filter we changed the `[calibrate.master_flat]` entries to match the given filter, but otherwise all settings were the same. This was automated using the `main.py` script.

The following header data may be useful

• `RET-POS1`: WPU HWP fast-axis angle
• `X_POLARP`: IR polarizer stage angle. To get the polarizer angle subtract ~90° (e.g., `X_POLARP=90` is horizontally polarized)
• `U_FLC`: FLC state, A is relaxed, B is active (sign convention is negative, so active is negative retardance)
• `U_CAMERA`: 1 or 2, 1 is transmission 2 is reflection
• `D_IMRANG`: Image rotator stage angle
• `U_QWP1`: SCExAO QWP 1 fast-axis angle
• `U_QWP2`: SCExAO QWP 2 fast-axis angle