FOS Wavelength Calibration Exposures George Hartig Space Tele8cope Science Inditute Instrument Science Report CAL/FOS048 October 1988 Abstract Optimal use of tbe interna.I ca.libra.tion la.mps for FOS wavelength caiibra.tion is discus.ed. Revised exposure times a.nd lamp selection rules, based on new lab caiibration data. and recent detector exposure limit analysis, arc presented.