The global and local count-rate screening limits for each COS configuration are given in Table 10.1. The limits are independent of observing mode (
TIME-TAG or
ACCUM). Compliance with these limits must be checked for all proposed COS targets by means of the
Exposure Time Calculator (ETC), which issues warnings if they are exceeded. In Phase I, all proposed targets must be screened against these limits. In Phase II, the results of more detailed target and field checks must be submitted with the observing proposal; details are provided in
Section 10.6. Note that the local count rate limits given in
Table 1.2 and the local count rate screening limits given in
Table 10.1 are not applicable to the 1055 and 1096 cenwaves of the COS G130M grating. For those modes, we expect lower local count rate limits. Calibration data required to derive the local count rate limits for those new cenwaves are still being worked on, and their values have not yet been accurately determined. We encourage users to check the
COS Web site for updates on those values.
