FGS Instrument Handbook for Cycle 24 . ... Fine Guidance Sensor Instrument Handbook for Cycle 24 > Appendix B: FGS1r PerformanceSummary > B.5 FGS1r: Third AMA Adjustment . B.5 FGS1r: Third AMA Adjustment . ... In late 2008, when HST?s science instrument compliment was reduced to ACS/SBC, WFPC2, and FGS, the reduced science pressure on access to HST assets motivated the decision to allocate the resources needed to re-optimize the FGS1r S-curves via an AMA adjustment. ...