
426 17. Detectors, Signal-to-Noise, and Detection Limits
In the absence of sky background and detector noise, the recorded signal
shows fluctuations due to "photon noise." The source of this noise arises from
statistical fluctuations in the number of recorded photons about some average
value, where the average number of detected photons is found from a large
number of identical exposures. Analysis of the effect of any noise contributor is
done in terms of SNR, the topic of one of the sections in this chapter
The final section of this chapter is a discussion of the detection limits in the
presence of noise for different types of observations ...