Space Telescope Science Institute   2.5 Basic Operations  3.1 The APT Visual Target Tuner (VTT)

Chapter 3:
Designing NICMOS
Observations


In this chapter . . .
The APT Visual Target Tuner (VTT)

In the preceding chapters, we provided an overview of the scientific capabilities of NICMOS and the basic layout and operation of the instrument. Subsequent chapters will provide detailed information about the performance and operation of the instrument. In this chapter, we briefly describe the conceptual steps which need to be taken when designing a NICMOS observing proposal. The scope of this description is to refer proposers to the relevant Chapters across the Handbook. The basic sequence of steps in defining a NICMOS observation are shown in a flow diagram in Figure 3.1, and are:

Estimate the exposure time to achieve the required signal to noise ratio and check feasibility (i.e., saturation limits). To determine exposure time requirements and assess whether the exposure is close to the brightness and dynamic range limitations of the detectors, the Exposure Time Calculator (ETC) should be used (see Chapter 9).

Figure 3.1: Specifying a NICMOS Observation

 

 2.5 Basic Operations  3.1 The APT Visual Target Tuner (VTT)
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