Demix distance criteria
Presently A team (CygA, CasA, TauA, VirA) are by default demixed if within 30 deg.
Maybe the criteria would be better to use the script from @yatawatta (https://git.astron.nl/RD/LINC/-/blob/master/scripts/tune_demixing_parameters.py) to determine whether or not the field needs demixing - this would hopefully result in less than 30 deg for VirA for example (ticket #42). Sarod suggested using a cut off value of 0.5 so that might be a sensible default but would also be good if users could adjust this in the json file.