Table 3 of LSST: From Science Drivers to Reference Design and Anticipated Data Products (2019) lists parallax precision from .6 mas to 1.3 mas depending upon magnitude. Section 3.3.5.1 of The LSST System Science Requirements Document (2018) states a requirement of “parallax accuracy of 1.0 mas over the course of the survey”. Astrometric Calibration in the LSST Pipeline (2024) states that the astrometric solution is being built to satisfy “LSST System Science Requirements Document (LPM-17) and related documents”. Can I assume that the specific list of parallax precisions listed in the 2019 document is used and not the more general specification from the 2018 document?
While the Science Requirements Document (SRD; 2018) is what we formally have to satisfy in terms of requirements, we have no plans to do anything that would limit the parallax accuracy, so the magnitude-dependent projections from the Science Book (2019) should still hold.
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