If we consider for example a point source with a uniform emission of magnitude 15 in the band J, being the sky airmass 1.2, and a seeing of 0.5, with the S2 objective inserted, for an integration time of 60 seconds, we could get:
where we have used data in Tab. 2.3 and eq. (2.5), (2.6) and expressed the result in Joule units.
Using eq. (2.7):
With the previously specified parameter we can get from formulae in Tab. 2.1:
The ETC for ISAAC in imaging observation mode with the input parameter as specified above predicts cnts.