STIS Instrument Handbook for Cycle 24

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14.1	Introduction

This chapter provides reference material to help you select your filter and detector configuration and determine your observing plan (e.g., total required exposure time, and number of exposures). This chapter is, for the most part, organized by filter and detector. For each imaging mode the following are provided:

•	A table of integrated system efficiencies and zero points for all the modes.

•	Plots and tables of throughput and sensitivity as a function of wavelength.

•	Where useful, plots of throughput on a logarithmic scale to show out-of band throughput (red leak or blue leak) for the different filters.

•	Plots of the time needed to achieve a desired signal-to-noise ratio vs. magnitude for broadband filters and vs. line flux for narrowband filters.

•	Plots of the PSF and encircled energies, along with a logarithmic-scale image of the PSF.

In addition, we provide the following sections:

•	Section 14.8 presents screening tables of bright object magnitudes for sources of different spectral type, for use in deciding if a MAMA imaging observation is safe.

•	Section 14.6 presents information on the geometry of the MAMA and CCD imaging modes.

•	Section 14.7 presents information on the changes of the PSF with position in the STIS field of view.

The sensitivities and dark currents adopted for calculating the figures and tables used in this chapter were projected before SM4 for a date of August 2008. Actual values for Cycle 24 will differ slightly. For the most up-to-date values, please consult the STIS ETC.