The steps we took to compute the dose map are;
-  Level 1 Event files for a specified month are obtained from archive.
-  Image data including I2, I3, S2, S3 CCDs  are  extracted from all event files.
-  All the extracted image data were merged to create a month long exposure map for the month.
-  The exposure map is opened with ds9, and check a distribution of count rates against energy.
     From this, estimate the upper threshold value. Any events beyond this upper threshold are
     assumed erroneous events such as bad pixels.
-  Using this upper threshold, the data is filtered, and create a cleaned exposure map for the month.
-  The exposure map from each month from the Sep 1999 is added up to create  a cumulative exposure
     map for each month.
-  Using fimgstatistic, we compute count rate statistics for each CCDs.
-  For observations with high data drop rates (e.g., Crab nebula, Cas A), we corrected the 
	observations by adding events.
Note: Counts and RMS's of Cumulative maps are lower than the previous months. This is because we excluded
extreme outliers.
Please check more detail plots at Telemetered Photon Dose Trend page.
-    MAR registered-photon-map in fits
 
Statistics:
# IMAGE     NPIX        MEAN           RMS              MIN     MAX
ACIS_mar08 6004901      9.11664        13.8470          0.0     748.0
 I2 node 0  262654      9.106190        3.637892        0.0      60.0
 I2 node 1  262654      9.751488        4.172524        0.0     318.0
 I2 node 2  262654      9.569290        3.679762        0.0     115.0
 I2 node 3  262654      9.473602        3.871092        0.0      51.0
 I3 node 0  262654      11.016567       4.050848        0.0      56.0
 I3 node 1  262654      12.447517       11.030034       0.0     274.0
 I3 node 2  262654      11.498349       4.231673        0.0      85.0
 I3 node 3  262654      10.713703       3.982495        0.0     193.0
 I2 node 0  262654      12.142482       4.415640        0.0     584.0
 I2 node 1  262654      12.378050       4.862955        0.0      83.0
 I2 node 2  262654      12.884773       4.564273        0.0     104.0
 I2 node 3  262654      12.367842       4.091962        0.0     351.0
 I3 node 0  262654      13.846431       10.162478       0.0     433.0
 I3 node 1  262654      16.080100       5.682849        0.0      81.0
 I3 node 2  262654      14.738193       4.571630        1.0      68.0
 I3 node 3  262654      13.032341       4.032328        0.0      82.0
 
-   Jul 1999 - Mar 2008  registered-photon-map in fits
 
Statistics:
 IMAGE        NPIX      MEAN          RMS              MIN    MAX
ACIS_total  6004901    1124.988         1544.517        0.0    67736.0
 I2 node 0  262654      844.725391      150.407198      0.0     3723.0
 I2 node 1  262654      893.186225      205.699687      0.0    13174.0
 I2 node 2  262654      909.140224      175.332953      0.0     3602.0
 I2 node 3  262654      911.612433      218.579365      0.0     4266.0
 I3 node 0  262654      964.253829      237.578268      0.0     5353.0
 I3 node 1  262654      999.318096      703.752880      0.0    18733.0
 I3 node 2  262654      886.630514      150.671487      0.0     3718.0
 I3 node 3  262654      874.941116      161.307122      0.0    16238.0
 I2 node 0  262654      1326.323905     166.710203      643.0  12821.0
 I2 node 1  262654      1409.129174     286.636748      683.0   7188.0
 I2 node 2  262654      1579.426310     300.910806      881.0  10256.0
 I2 node 3  262654      1528.340653     231.714729      871.0  18058.0
 I3 node 0  262654      2417.931537     1263.135614     962.0  10787.0
 I3 node 1  262654      3624.683329     1775.079595     0.0    11724.0
 I3 node 2  262654      2626.187420     801.136017      848.0   5810.0
 I3 node 3  262654      1951.337986     318.893251      1022.0  7903.0
 
-   MAR 2008 dose PNG image
 
-   MAR I3 dose PNG image
 
-   MAR S3 dose PNG image
 
-   TOTAL JUL 1999 - MAR 2008 dose PNG image
 
-   TOTAL I3 dose PNG image
 
-   TOTAL S3 dose PNG image