|Space Telescope Science Institute|
|COS Instrument Handbook|
It is useful to compare the BOP limits with the 30,000 counts/s limit on TIME-TAG exposures discussed in Section 5.2.1. In the FUV, a steep spectrum could exceed the BOP limit of 15,000 counts/s per detector segment without exceeding the TIME-TAG limit. In the NUV, the BOP limit is considerably higher; a target that is perfectly safe could be far too bright to observe in TIME-TAG mode.