Reproducibility in reading the ToO.ecsv ledger

[araichoor]

The original pre-shutdown 2020 Main ToO.ecsv file (and SV3) do not have a TIMESTAMP column.

That is potentially problematic to rerun fiber assignment, as the ToO.ecsv file will evolve.
See desihub/desitarget#761.

[geordie666]

Although the Main Survey ToO ledger exists, we have only used it to perform dedicated-like TOO_TYPE==TILE observations, not FIBER-like observations. As TIMESTAMP only really needs to apply to FIBER-like observations, my plan is just to add TIMESTAMP to the Main Survey ToO ledger and not be concerned about the existing TILE observations. If you disagree, I could also just back-date all of the TOO_TYPE==TILE observations to an appropriate TIMESTAMP?

[araichoor]

ah right, sorry I forgot about that TILE/FIBER type (even though you reminded it to me recently...)
thanks a lot for bringing that up!

I should then apply this TIMESTAMP cut only if too_tile=False in this create_too() function, ie when designing Main-survey tiles:

fiberassign/py/fiberassign/fba_launch_io.py

Lines 1184 to 1186 in 802de4c

	too_tile (optional, defaults to False): if False, we only keep TOO_TYPE!="TILE",
	if True, we do not cut on TOO_TYPE, hence keeping both TOO_TYPE="FIBER" *and*
	TOO_TYPE="TILE" for ToO dedicated tiles (boolean)

right?
That should solve the issue with no action needed on your side?

And a clarification: I m a bit confused by your message: there is only one ToO.ecsv file, right (in $DESI_SURVEYOPS/mtl/main/ToO/)? that file will contain TOO_TYPE=TILE or FIBER targets (though for now, only TILE are there).

[geordie666]

Correct, I think that if you only apply the TIMESTAMP for TOO_TYPE==FIBER targets, then everything will be OK.

And a clarification: I m a bit confused by your message: there is only one ToO.ecsv file, right (in $DESI_SURVEYOPS/mtl/main/ToO/)? that file will contain TOO_TYPE=TILE or FIBER targets (though for now, only TILE are there).

Everything you say in the above is correct (there is also a ToO ledger in $DESI_SURVEYOPS/mtl/sv3/ToO/, but that's irrelevant to this discussion.

[araichoor]

ok perfect, thanks for the confirmation.
this commit now applies the TIMESTAMP cut only if too_tile=False: 0d9601e

[araichoor]

This is addressed in the merged #394.