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(Stephens) The GLAST data as planned to be distributed does not have pointings in the traditional sense and there will be a lot of data that doesn't correpsond to a proposal from the GI program. The RA_SCX, DEC_SCX, RA_SCZ, DEC_SCZ keywords are mostly meaningless for the data as the spacecraft is constantly moving. The center of the "field of view" for the data extraction is already identify by the Data Subspace Selection (DSS) keywords. It would be possible and might be of use to duplicate this in the OBJECT keyword but I think the OBS_ID keyword would go away.
(McEnery) I think that the OBS_ID might not be very useful. It is ambiguous when an observation starts. The LAT does not go into a different mode or start a new run when we repoint, so it would not be obvious when to start tagging events with a new OBS_ID. Also, as Tom points out, we will likely spend most of our time in survey mode even after year 1. I think that it may be useful to have RA_SCX, DEC_SCX, RA_SCZ, DEC_SCZ because they define the orientation of the LAT for each event.
5. MC_TRUTH keyword
(Digel) I think that the original intent was that this keyword indicate whether the data are entirely Monte Carlo truth values (i.e., actual directions, energies, etc.). We do not actually have files like this, and I propose removing this keyword. gtobsssim does add a column MC_SRC_ID to the files it generates, but this is easy enough to check for without the MC_TRUTH keyword.
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(Foschini) Perhaps it can be useful to have a DEADC keyword with the average deadtime correction (i.e. the complementary to deadtime value) applied to the events in the file.
(McEnery) I agree that we should have livetime included as a column in the events file.
14. Event summary++
(Digel) LS-002 is an event summary, intended to have information for higher-level analyses. The GSSC expects (reasonably) to receive this summary for every event that is telemetered to the ground (and that is not discarded early in the process as obviously background to save disk space at the ISOC).
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