|COS Instrument Handbook for Cycle 25|
13.1 The information in this chapter will help you to select a detector, grating configuration, and observing aperture, and to develop your observing plan. For each grating, the following information is provided:
• Plots of signal-to-noise ratio as a function of STMAG, Fλ, and exposure time.Note that the quoted sensitivities are estimates for mid-Cycle 23 (April 2016). The COS Exposure Time Calculator (ETC) will be updated as the instrument’s sensitivity continues to evolve. See the COS website for the latest information.