What are the count rate limits and what is the Petal Pattern mode?
The mission planning count rate limits are as follows. For all observations, the global count rate limit is 80 k/s NUV and 15 k/s FUV. For AIS the local count rate limit is 30 k/s NUV and 7 k/s FUV. For all other observations, the local count rate limit is 30 k/s NUV and 5 k/s FUV. For local NUV count rates between 5 k/s and 30 k/s, the Petal Pattern mode must be used. Note that the count rate limits quoted here are the *predicted* rates for the nominal detector response. The actual rates for sources at the detector are generally lower, due to dead time (FAQ 103) and sensitivity variations over the detector (FAQ 109). (The data analysis pipeline corrects for these and other effects in preparing data products.) We observe objects with 5k/s < NUV < 30 k/s in the Petal mode so as not to cause more local detector fatigue in a given location than takes place during non-Petal-mode observation methods using the 5 k/s count rate limit. For survey types other than the AIS we accomplish this by
