Gain Notes for Revolution 419 JEM-X1: An interesting revolution with poor gain smoothing on one of the sources. Only data upto about IJD=2270.5 can be used if processed with the gain history table generated automatically by ISDC. This is caused by outliers in the source 4 gain history table, created by strong grey filtering of the data cutting out most of the calibration data for this weak source. This problem is now fixed by using OSA 6.0 and later versions. The corrected gain history table, with the outlying points corrected, is delivered to ISDC as an instrument characteristics (IC) file. The analysis scripts can find these IC files if one exists for a particular revolution, and use it instead of the automatically generated file. If you don't have OSA 6.0 installed, or do not have the latest IC files us the following quick fix. The results shown here without the label `uncorrected' have been derived using the IC gain history. QUICK FIX: Download the corrected gain history table that has all the source four outliers removed. This is to be found in column `Other data and results' of the table containing these notes. Put the file in your own private directory say , and unzip it (gzip -d JMX1_gainHistoryIC_rev0419_001.fits.gz). When you run the OSA GUI you must correct the hidden parameter gainHist so that it points the the corrected gain history table: COR_gainHist = /JMX1_gainHistoryIC_rev0419_001.fits[JMX1-GAIN-OCL,1] Performing the Xe line analysis using this IC table, we get a fine Xe position for the entire revolution except for the first few science windows after the initial activation of the instrument. These SCWs should be avoided when doing any analysis that requires fine energy determination. JEM-X2: No data and no gain history for this unit CAO 30/8/2007