ACIS
ACIS DOSE Registered-Photon-Map
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.
Please check more detail plots at Telemetered Photon Dose Trend page.
Statistics: # IMAGE NPIX MEAN RMS MIN MAX ACIS_sep25 6004901 3.675 4.240 0.0 775 I2 node 0 262654 3.289934 2.080125 0.0 46.0 I2 node 1 262654 3.658276 2.398769 0.0 468.0 I2 node 2 262654 3.634284 2.209737 0.0 65.0 I2 node 3 262654 3.316606 2.255345 0.0 324.0 I3 node 0 262654 4.232411 2.388641 0.0 74.0 I3 node 1 262654 4.756624 2.583540 0.0 106.0 I3 node 2 262654 4.543457 2.457039 0.0 59.0 I3 node 3 262654 3.922250 2.270477 0.0 90.0 S2 node 0 262654 4.779075 2.660927 0.0 517.0 S2 node 1 262654 5.158645 2.864374 0.0 247.0 S2 node 2 262654 5.056124 3.175556 0.0 775.0 S2 node 3 262654 4.801867 2.808554 0.0 437.0 S3 node 0 262654 6.474962 2.796754 0.0 56.0 S3 node 1 262654 7.698825 3.225513 0.0 64.0 S3 node 2 262654 7.443792 2.932182 0.0 40.0 S3 node 3 262654 6.423599 2.689934 0.0 35.0
Statistics: IMAGE NPIX MEAN RMS MIN MAX ACIS_total 6004901 2747.564 3469.063 0.0 169725 I2 node 0 262654 2386.048530 485.218630 511.0 15988.0 I2 node 1 262654 2516.906451 711.692571 522.0 167719.0 I2 node 2 262654 2543.493216 540.681459 546.0 17706.0 I2 node 3 262654 2547.773052 662.865684 505.0 36848.0 I3 node 0 262654 2754.231545 685.370524 506.0 15530.0 I3 node 1 262654 2832.835938 1758.423945 531.0 56077.0 I3 node 2 262654 2540.193497 477.089603 497.0 15573.0 I3 node 3 262654 2515.694663 514.060100 477.0 36710.0 S2 node 0 262654 3206.411573 518.977237 1728.0 22666.0 S2 node 1 262654 3406.664500 779.024544 1903.0 21647.0 S2 node 2 262654 3778.080637 783.308422 2316.0 34070.0 S2 node 3 262654 3735.175553 641.355273 2040.0 88110.0 S3 node 0 262654 5680.364936 3073.003823 2496.0 55544.0 S3 node 1 262654 6896.343448 2409.828024 0.0 83602.0 S3 node 2 262654 5630.337818 1383.547054 2656.0 27715.0 S3 node 3 262654 4430.592733 784.041535 2660.0 26810.0
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Jun 2025 | Mar 2025 | Dec 2024 | Sep 2024 |
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The Mean Detrended CTI
We report CTIs with a refined data definition. CTIs were computed for the temperature dependency corrected data. Please see CTI page for detailed explanation. CTI's are computed for Mn K alpha, and defined as slope/intercept x10^4 of row # vs ADU. Data file: here
Imaging CCDs
Spectral CCDs
Backside CCDs
Focal Plane Temperature
Sep 2025 Focal Temperature
The Mean (max) FPT: | |
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-107.53 | +/- 7.69 C |
Mean Width: | |
0.8 | +/- 0.58 days |
Averaged Focal Plane Temperature
We are using 10 period moving averages to show trends of peak temperatures and peak widths. Note, the gaps in the width plot are due to missing/corrupted data.
Focal Plane Temperature, Sun Angle and Altitude
Bad Pixels
The plots below were generated with a new warm pixel finding script. Please see Acis Bad Pixel Page for details.
Front Side CCDs
Back Side CCD (CCD5)
Science Instrument Background Rates
Name | Low (keV) | High(KeV) | Description |
---|---|---|---|
SSoft | 0.00 | 0.50 | Super soft photons |
Soft | 0.50 | 1.00 | Soft photons |
Med | 1.00 | 3.00 | Moderate energy photons |
Hard | 3.00 | 5.00 | Hard Photons |
Harder | 5.00 | 10.00 | Very Hard photons |
Hardest | 10.00 | Beyond 10 keV |
ACIS Rejected Events
The links below are plots of stat1 quantities, showing on-board rejected events. The average EVTSENT, DROP_AMP, DROP_POS, DROP_GRD, THR_PIX, and maximum BERR_SUM obtained from L1 acis*stat1.fits files are plotted for each observation. CTI observations are plotted separately from regular science observations.
Column definitions:
- EVTSENT - number of events sent in data record
- DROP_AMP - number of discarded events due to corrected amplitude
- DROP_POS - number of discarded events due to CCD position
- DROP_GRD - number of discarded events due to grade code
- THR_PIX - number of pixels above respective threshold level
- BERR_SUM - number of pixel bias errors so far in science run
Note the half-life decline of the CTI source is clearly evidenced in the steady janline of EVTSENT.
CCD3 Observations
CTI | Science |
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CCD7 Observations
CTI | Science |
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ACIS Gain Trends
We computed ACIS gain and offset from ACIS event1 files used in CTI computation, following the step described by C. Grant ACIS gain @ -120C page.
Instead computing gains and offsets from individual observations, we combined all data from each month and computed an monthly averaged gain and offset.
The following plots show CCD3 and CCD5 gains and offset trends.
CCD 3 | |
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CCD 5 | |
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HRC
DOSE of Central 4K Pore-Pairs
Please refer to Maximum Dose Trends for more details.
IMAGE NPIX MEAN STDDEV MIN MAX HRCI_09_2025.fits 16777216 0.069 0.265 0.000 10.000
IMAGE NPIX MEAN STDDEV MIN MAX HRCI_08_1999_09_2025.fits 16777216 na na na na
IMAGE NPIX MEAN STDDEV MIN MAX HRCS_09_2025.fits 16777216 0.012 0.111 0.000 4.000
IMAGE NPIX MEAN STDDEV MIN MAX HRCS_08_1999_09_2025.fits 16777216 na na na na
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Max dose trend plots corrected for events that "pile-up"
in the center of the taps due to bad position information.
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Jun 2025 | Mar 2025 | Dec 2024 | Sep 2024 |
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Jun 2025 | Mar 2025 | Dec 2024 | Sep 2024 |
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Gratings
Grating Trends/Focus
We plot the width of the zero order streak of ACIS/HETG observations and the width of the zero order image for HRC/LETG observations of point sources. No significant defocusing trend is seen at this time. See Gratings Trends pages.
PCAD
ACA Trending
ACIS |
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HRCI |
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HRCI |
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Gyro Bias Drift
Radiation History
Radiation Count Rates of Sep 2025
Sun Spot History (See:NOAA Page)

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Trending
Critical Trends
ACIS Temperatures - Daily Maximums | |||||||
---|---|---|---|---|---|---|---|
MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
1pdeaat | 0.001 | 0.002 | (2.99+/-0.04)e2 | 1.24 +/- 1.33 | K | PSMC DEA PS A TEMP |
HRMA Computed Averages - Daily Maximums | |||||||
---|---|---|---|---|---|---|---|
MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
obaavg | -0.014 | 0.001 | (2.98+/-0.02)e2 | -1.27 +/- 0.65 | TEMP | OBA/TFTE |
EPHIN Temperatures - Daily Maximums | |||||||
---|---|---|---|---|---|---|---|
MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
teio | 0.026 | 0.009 | (3.30+/-0.22)e2 | 2.97 +/- 3.64 | K | EPHIN ELECTRONICS HOUSING TEMP | |
tephin | 0.008 | 0.003 | (3.39+/-0.08)e2 | 2.15 +/- 2.13 | K | EPHIN SENSOR HOUSING TEMP |
S/C Main Temperatures - Daily Maximums | |||||||
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MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
tcylfmzm | 0.020 | 0.004 | (3.13+/-0.10)e2 | 1.24 +/- 1.91 | K | CNT CYL TEMP:-Z SIDE UNDER LAE-1 | |
tcylfmzp | 0.020 | 0.004 | (3.16+/-0.09)e2 | 1.12 +/- 1.75 | K | CNT CYL TEMP:-Z SIDE UNDER LAE-2 |
S/C Ancillary Temperatures - Daily Maximums | |||||||
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MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
tfssbkt1 | 0.015 | 0.012 | (3.50+/-0.29)e2 | 3.75 +/- 4.12 | K | FSS BRAC | |
tfssbkt2 | 0.017 | 0.013 | (3.45+/-0.29)e2 | 3.80 +/- 4.17 | K | FSS BRAC | |
tsctsf1 | 0.004 | 0.002 | (3.24+/-0.05)e2 | 0.53 +/- 1.31 | K | SC-TS FITTING -1 TEMP | |
tsctsf6 | 0.003 | 0.002 | (3.24+/-0.05)e2 | 0.36 +/- 1.36 | K | SC-TS FITTING -6 TEMP |
MUPS - Daily Maximums | |||||||
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MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
pm1thv1t | 0.016 | 0.007 | (3.52+/-0.16)e2 | -1.18 +/- 2.51 | K | MUPS 1 THRUSTER VALVE 01 TEMP | |
pm2thv1t | 0.063 | 0.022 | (3.18+/-0.51)e2 | 0.41 +/- 7.55 | K | MUPS 2 THRUSTER VALVE 01 TEMP | |
pm1thv2t | 0.015 | 0.007 | (3.54+/-0.16)e2 | -0.79 +/- 2.65 | K | MUPS 1 THRUSTER VALVE 02 TEMP | |
pm2thv2t | 0.059 | 0.023 | (3.16+/-0.55)e2 | 1.27 +/- 8.00 | K | MUPS 2 THRUSTER VALVE 02 TEMP | |
pline02t | 0.023 | 0.005 | (3.36+/-0.12)e2 | 0.78 +/- 2.28 | K | PROP LINE TEMP 02 | |
pline03t | 0.025 | 0.006 | (3.29+/-0.14)e2 | 0.57 +/- 2.15 | K | PROP LINE TEMP 03 | |
pline04t | 0.023 | 0.005 | (3.17+/-0.11)e2 | 2.82 +/- 2.29 | K | PROP LINE TEMP 04 |
Quarterly Trends
- PCAD FTS Temperature and Gradient
Previous Quarter | |||||||
MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
ohrthr27 | 4.531e-04 | 6.225e-05 | (2.97+/-0.00)e2 | -0.00 +/- 0.02 | K | RT 20 : PERISCOPE | |
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ohrthr42 | 0.003 | 3.019e-04 | (2.97+/-0.01)e2 | 0.51 +/- 0.12 | K | RT 133: PERISCOPE | |
ohrthr43 | 0.003 | 3.296e-04 | (2.97+/-0.01)e2 | 0.43 +/- 0.16 | K | RT 134: PERISCOPE | |
oobagrd3 | -2.965e-04 | 5.231e-05 | -0.33 +/- 0.12 | 0.02 +/- 0.04 | K | RT 505 TO RT 504: PERISCOPE GRADIENT MONITOR | |
oobagrd6 | 4.743e-05 | 5.770e-06 | 0.13 +/- 0.01 | 0.01 +/- 0.00 | K | RT 507 TO RT 506: PERISCOPE GRADIENT MONITOR |
- SIM Temperature
Previous Quarter | |||||||
MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
3btu_bpt | -0.010 | 0.002 | (2.66+/-0.04)e2 | 0.02 +/- 1.27 | K | BTU BASEPLATE (+X)), ABORT HTR TSC2 | |
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3tsmxcet | -0.046 | 0.018 | (2.41+/-0.41)e2 | 0.66 +/- 5.09 | K | -X TURTLE SHELL NR HRC CEA | |
3tsmxspt | -0.332 | 0.081 | (4.39+/-1.91)e2 | 20.84 +/- 25.54 | K | -X TURTLE SHELL NR ACIS SS |
- SIIM Electronics
Previous Quarter | |||||||
MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
agrndadc | -3.242e-06 | 5.164e-07 | -(3.83+/-0.93)e-4 | (3.81+/-1.50)e-4 | V | Analog fround A/D convert reading | |
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fatabadc | -2.463e-05 | 2.878e-05 | 4.99 +/- 0.08 | 0.01 +/- 0.00 | V | FA Tab Position Sensor A/D Converter | |
n15vadc | 4.888e-07 | 1.280e-07 | -15.02 +/- 0.00 | -(2.92+/-7.56)e-5 | V | -15V Power Supply A/D Converter Reading | |
p15vadc | -3.171e-07 | 1.174e-07 | 14.96 +/- 0.00 | -(4.74+/-10.21)e-5 | V | +15V Power Supply A/D Converter Reading | |
p5vadc | 3.783e-06 | 7.379e-07 | 4.94 +/- 0.00 | (7.42+/-5.60)e-4 | V | +5V Power Supply A/D Converter Reading | |
tsctabadc | -1.713e-04 | 0.001 | 4.97 +/- 0.17 | 0.14 +/- 0.17 | V | TSC Tab Position Sensor A/D converter |
Spacecraft Motions
TSC and FA Cummulative Moter Distance

HETG and LETG Cummulative Insertion Counts

HETG/LETG Insertion/Retraction Angle

Reaction Wheel Rotations
