Up until recently, the global analogue attenuation for each observation was only in the schedule database, not in the metafits files. The ATTEN_DB card in the primary header of the metafits file now contains the global attenuation in decibels, and cotter should use the attenuation difference between calibrator and target observations to do the flux scaling correctly. If the card isn't present, the attenuation should default to 1.0 dB.
Up until recently, the global analogue attenuation for each observation was only in the schedule database, not in the metafits files. The ATTEN_DB card in the primary header of the metafits file now contains the global attenuation in decibels, and cotter should use the attenuation difference between calibrator and target observations to do the flux scaling correctly. If the card isn't present, the attenuation should default to 1.0 dB.