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STIS Status. TIPS, September 17, 2009 Charles Proffitt for the STIS team. STIS Status: Topics. STIS SMOV & Calibration Overview STIS CCD status summary NUV Dark current update. STIS SMOV Status. All STIS SMOV observations complete as of September 6, 2009 Most STIS SMOV analysis complete - PowerPoint PPT Presentation
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STIS Status
TIPS, September 17, 2009
Charles Proffitt for the STIS team
STIS Status: Topics
• STIS SMOV & Calibration Overview
• STIS CCD status summary• NUV Dark current update
STIS SMOV Status• All STIS SMOV observations complete as of September 6, 2009• Most STIS SMOV analysis complete
– Final superbias & super-dark reference files for SMOV period have been delivered
– New CCD reference file delivered• Readnoise, gain, and CTE parameters
– CCD TDS reference files delivered• Time-dependent sensitivity corrections to flux calibration
• Open issues in STIS SMOV analysis– Waiting for additional Cycle 17 calibration observations to finalize
MAMA TDS updates• Changes from pre-repair predictions appear to be small (< 3%)
– Monitoring of NUV MAMA dark is being continued by cycle 17 calibration program 11857
– Detailed writeups still pending for most activities
STIS Activity PropID STIS SMOV Program Title Analysis Lead
Visits Done
Total Visits
Status
STIS02 11347 Memory Load and Dump BS 1 1 Complete
STIS03 11348 Science Data Buffer Check BS 3 3 Complete
STIS04 11349 Mechanism Mini-Functional TW 1 1 Complete
STIS05 11399 CCD Anneal (two anneal iterations) MW 6 6 Complete
STIS06 11382 CCD Functional DL 4 4 Complete
STIS07 11404 CCD Dark & Bias Monitor MW 90 105 Complete
STIS08 11383 Aperture Wheel & Lamp Functional WZ 2 2 Complete
STIS09 11384 STIS-to-FGS Alignment CP 1 1 Complete
STIS10 11385 CCD Spectral Format Verification WZ 1 1 Complete
STIS11 11386 External Focus Check CP 4 3+1 Complete
STIS12 11387 Corrector and Focus Alignment CP - 8 Contingency
STIS13 11388 CCD External Spectroscopic Quality TG 1 1 Complete
STIS14 11400 CCD CTI Check PG 1 1 Complete
STIS15 11401 CCD Spectroscopic Throughputs DL 3 3 Complete
STIS16 11389 CCD Image and Pointing Stability TG 1 1 Complete
STIS17 11350 FUV MAMA HV Recovery TW 4 4 Complete
STIS18 11351 NUV MAMA HV Recovery TW 4 (+2F) 4 (+2F) Complete
STIS19 11390 FUV MAMA Dark Measure CP 10 10 Complete
STIS20 11402 NUV Dark Monitor CP 42(+3F) 20+52 Complete
STIS21 11391 FUV Optical Format Verification WZ 2 2 Complete
STIS22 11392 NUV Optical Format Verification WZ 2 (+2F) 2 (+2F) Complete
STIS23 11393 FUV MAMA Spectroscopic Quality TG 1 1 Complete
STIS24 11394 NUV MAMA Spectroscopic Quality TG 1 1 Complete
STIS25 11403 MAMA Spectroscopic Throughputs DL 3 3 Analysis being finalized
STIS26 11395 MAMA Image Stability TG 2 2 Complete
STIS Cycle 17 Calibration
• Analysis leads assigned for all programs– New leads will also track execution
• Most Calibration Programs have started– Routine dark monitors have begun
• Routine delivery of weekly bias and dark reference files– Automated Bias & Dark Pipeline still under work
– P-flat data collection has begun • SMOV plan deferred this calibration to cycle 17
– Data being combined with SMOV results to improve calibration
• Cycle 17 data especially important for CTE calibration
STIS Calibration PlanPropID STIS SMOV Program Title Analysis Lead Start Date
11843 CCD Performance Monitor VD 01-Sep-2009
11844/11845 CCD Dark Monitor (part 1 & 2) MW 03-Aug-2009
11846/11847 CCD Bias Monitor (part 1 & 2) MW 03-Aug-2009
11848 CCD Read-noise Monitor VD 10-Sep-2009
11849 CCD Hot-pixel Annealing MW 23-Jul-2009
11852 CCD Spectroscopic Flats SN 10-Aug-2009
11853 CCD Imaging Flats SN 27-Aug-2009
11858 CCD Spectroscopic Dispersion IP 20-Aug-2009
11850 CCD Sparse Field CTE Internal VD 03-Jul-2009
11854 CCD Full Field Sensitivity VD Jan-Mar, 2010
11851 Slit Wheel Repeatability WZ 17-Aug-2009
11855 CCD Spectroscopic Sensitivity Monitor RO 10-Aug-2009
11859 MAMA Dispersion Solutions IP 20-Aug-2009
11856 MAMA Full Field Sensitivity VD May, 2010
11860 MAMA Sensitivity and Focus Monitor RO 03-Sep-2009
11857 MAMA Dark Monitor WZ 09-Sep-2009
11863 MAMA Fold Distribution TW Nov, 2009
11861 MAMA FUV Flats TA 17-Aug-2009
11862 MAMA NUV Flats TA 17-Aug-2009
11864 MAMA Anomalous Recovery TW contingency
11865 COS Flux Standard RB Oct, 2009
11866 Echelle Grating Blaze Function Zero Points PG Nov, 2009
11999 JWST Calibration from a Consistent Absolute Calibration of Spitzer & Hubble
RB Oct, 2009 - Sep 2010
STIS CCD Status• Dark current, read-noise, and
CTE measured
• Read noise slightly greater than pre-repair
– Gain = 1 was 5.3 now 5.8 e-
– Gain = 4 was 7.8 now 8.3 e-
• Observed charge Transfer Efficiency (CTE) in 2009 close to extrapolation of old trend (CTI = 1 - CTE).
– CTE losses becoming very large for faint sources
STIS CCD Status - cont• Current pipeline CTE algorithm assumes constant “spurious
charge” over detector at a given time– Can get better CTE correction if this allowed to vary over detector
– This will require modest changes to CALSTIS
– For now will use compromise value with old algorithm
CCD Dark Current Behavior
• Median CCD dark current in 2009 slightly above extrapolated trend from 2004
• CCD Dark shows increasing spatial dependence over time – about 40% lower near row 900 as compared to center of chip!
CCD Sensitivity Changes
Advantages of E1 position
• For many years, we have had defined “E1” positions for CCD near row 900 of STIS long slit– Closer to default readout amplifier
– Reduced CTI losses
– Reduced effective dark current
– Less contamination by CTE tails of CR & hot pixels
• While we have advertised advantages of E1 position for years in IHB and other documentation, ETC does not distinguish between center and E1 posistion– GO need to manually estimate CTE losses
• Re-emphasize importance of using E1 position to GOs• For cycle 19 ETC, should include variations in dark current &
CTE as function of slit position
NUV dark update• Post SM4 NUV dark current (black dots) much higher than expected
– model as “expected dark” + “something extra”• Model as the “expected dark” (orange curve below) declining according to old
behavior + an extra component Ae-(E/T) e-t/
• “extra” term appears to have stronger T dependence (E ≈ 1.8 eV vs 1.5 eV)
• Plot below compares different e-folding times for extra component =100 d (red) & = ∞ (blue)
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