I took the following steps to generate the representative noise model.
Ran generate_bigfrac.py
Substeps I did for sanity checks:
* `plot_supersampled_PSFs.py`
* `plot_att_err.py`
* `plot_PRF_comparison.py
Ran ctd_avg_field_angle_avg.py This has a built-in sanity check: it writes
the PRF_vs_temperature.pdf plot.
Ran noise_model.py
Ran plot_noise_model.py