12432( 3) - 23-Nov-2010 15:22:00 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12432 Version: 3 Check-in Time: 23-Nov-2010 15:22:00 STScI Edit Number: 0 Title COS FUV Detector Gain Sag vs. High Voltage ------------------------------------------------------------------------------------ Type Cycle CAL/COS 18 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. David J. Sahnow The Johns Hopkins University CoI: Dr. Alan D. Welty Space Telescope Science Institute N CoI: Dr. Derck L. Massa Space Telescope Science Institute N CoI: Dr. Cristina Oliveira Space Telescope Science Institute N CoI: Dr. Rachel A. Osten Space Telescope Science Institute N CoI: Dr. Charles R. Proffitt Computer Sciences Corporation N CoI: Dr. Jason McPhate University of California - Berkeley N ------------------------------------------------------------------------------------ Abstract Recent data shows that there is signifcant gain sag on the FUV detector, particularly at the locations of the Lyman-alpha lines on Segment B. If nothing is done, these areas will eventually become unresponsive, leaving holes in the spectra. One way to increase the gain is to raise the high voltage on the MCPs. We will collect spectra of a standard star after increasing the high voltage on both segments back to the initial on-orbit values of 178 and 175 for Segments A and B. Several dark exposures will also be taken at the higher voltage. ------------------------------------------------------------------------------------ Observations Description ------------------------ Visit UP: FUV power cycle and Special Commands in order to increase the HV max levels to 178 (A) and 175 (B), followed by ramping up the HV to these levels. Visit DK: Five 1330 second dark exposures at the increased HV levels. Visit HV: Observations of standard star WD1057+719 at the increased HV levels, using G160M/1577 at all 4 FP-POS positions. Visit DN: Return the HV to nominal values (169 and 167) via Special Commanding. Visit LV: Repeat of Visit HV, but at nominal voltage levels. Real Time Justification ----------------------- Calibration Justification ------------------------- The data collected will be used to determine if a "permanent" high voltage increase should be made in order to increase the gain of the microchannel plates. 12432( 3) - 23-Nov-2010 15:22:00 - [ 2] Additional Comments ------------------- IMPORTANT Scheduling Constraint: The Sequence UP, DK, HV and DN MUST be scheduled during the same SAA-Free time with no other COS observations between any of the visits. Also, schedule as soon as possible after the calendar's 12046 visit with no other COS/FUV between the 12046 and 1242301. Visit LV has been specified to occur within 2 days of Visit DN, but this is somewhat flexible, and can be adjusted if necessary. ------------------------------------------------------------------------------------ 12432( 3) - 23-Nov-2010 15:22:00 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WD1057+719 STAR, DA RA=11H00M34.2200S +/- 0.1", J2000 V = 14.68 DEC=+71D38'2.99" +/- 0.1" Reference Frame: ICRS Comments: HST FASTEX standard PM, coords from USNOB GSC2 coords are 11:00:34.25, +71:38:02.97 1997.19 epoch Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.00973 -0.02 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 12432( 3) - 23-Nov-2010 15:22:00 - [ 4] Visit: DK Visit Requirements: AFTER UP BY 0 Orbits TO 2 Orbits On Hold Comments: Additional Comments: Take five dark exposures at higher than nominal voltage. Must be done after the HV is increased, and without any intervening SAAs. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 DARK COS/FUV TIME-TA DEF DEF BUFFER-TIME=1330 1 1330.0 S G ------------------------------------------------------------------------------------------------------------------------------------ 2 DARK COS/FUV TIME-TA DEF DEF BUFFER-TIME=1330 1 1330.0 S NEW ALIGNMENT G ------------------------------------------------------------------------------------------------------------------------------------ 3 DARK COS/FUV TIME-TA DEF DEF BUFFER-TIME=1330 1 1330.0 S NEW ALIGNMENT G ------------------------------------------------------------------------------------------------------------------------------------ 4 DARK COS/FUV TIME-TA DEF DEF BUFFER-TIME=1330 1 1330.0 S NEW ALIGNMENT G ------------------------------------------------------------------------------------------------------------------------------------ 5 DARK COS/FUV TIME-TA DEF DEF BUFFER-TIME=1330 1 1330.0 S NEW ALIGNMENT G ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ DARK 1 COS/FUV TIME-TA DEF DEF none none none none 1 N/A G DARK 2 COS/FUV TIME-TA DEF DEF none none none none 1 N/A G DARK 3 COS/FUV TIME-TA DEF DEF none none none none 1 N/A G DARK 4 COS/FUV TIME-TA DEF DEF none none none none 1 N/A G DARK 5 COS/FUV TIME-TA DEF DEF none none none none 2 N/A G 12432( 3) - 23-Nov-2010 15:22:00 - [ 5] Visit: DN Visit Requirements: AFTER HV BY 0 Orbits TO 1 Orbits; PARALLEL On Hold Comments: Additional Comments: Return to nominal HV levels. Note that the HV Max levels are left at 178 and 175. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 DARK S/C DATA NONE 1 0 S QASISTATES COS SI OPERATE OPERATE; QASISTATES COS FUV HVLOW HVLOW; QASISTATES COS NUV HVSAA HVSAA Comments: Return to the nominal HV levels ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ DARK 1 S/C DATA NONE none none none none 1 N/A 12432( 3) - 23-Nov-2010 15:22:00 - [ 6] Visit: HV Visit Requirements: AFTER DK BY 0 Orbits TO 2 Orbits On Hold Comments: Additional Comments: Standard star observation at higher than nominal voltage. To be done after the HV is increased, and without any intervening SAAs. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 WD1057+719 COS/NUV ACQ/SEA BOA MIRRORA SCAN-SIZE=2, STEP-SIZE=1.767 1 35 S RCH Comments: Spectroscopic acquisition - step 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 WD1057+719 COS/NUV ACQ/IMA BOA MIRRORA 1 35 S GE Comments: Spectroscopic acquisition - step 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=1, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 4 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=2, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 5 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=3, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 6 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=4, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WD1057+719 1 COS/NUV ACQ/SEA BOA MIRRORA none none none none 1 N/A RCH WD1057+719 2 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE WD1057+719 3 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G WD1057+719 4 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G WD1057+719 5 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G WD1057+719 6 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G 12432( 3) - 23-Nov-2010 15:22:00 - [ 7] Visit: LV Visit Requirements: AFTER DN BY 1 Orbits TO 2 D On Hold Comments: Additional Comments: Standard star observation at nominal voltage. To be executed after the HV is returned to its nominal value. Aside from voltage levels, identical to visit HV. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 WD1057+719 COS/NUV ACQ/SEA BOA MIRRORA SCAN-SIZE=2, STEP-SIZE=1.767 1 35 S RCH Comments: Spectroscopic acquisition - step 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 WD1057+719 COS/NUV ACQ/IMA BOA MIRRORA 1 35 S GE Comments: Spectroscopic acquisition - step 2 ------------------------------------------------------------------------------------------------------------------------------------ 3 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=1, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 4 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=2, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 5 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=3, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 6 WD1057+719 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=125, FP-POS=4, 1 395 S G FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WD1057+719 1 COS/NUV ACQ/SEA BOA MIRRORA none none none none 1 N/A RCH WD1057+719 2 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE WD1057+719 3 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G WD1057+719 4 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G WD1057+719 5 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G WD1057+719 6 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G 12432( 3) - 23-Nov-2010 15:22:00 - [ 8] Visit: UP Visit Requirements: PARALLEL On Hold Comments: Additional Comments: This visit does an FUV HV power cycle (HVLOW to Operate, followed by Operate to HVLOW) in order to change the maximum allowd HV levels for the FUV detector, then modifies the levels and brings up the HV. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 DARK S/C DATA NONE 1 1235 S SPEC COM INSTR ELSETHVMAX; QASISTATES COS SI OPERATE OPERATE; QASISTATES COS FUV BOOT HVLOW; QASISTATES COS NUV HVSAA HVSAA; QESIPARM MAXHVA 178; QESIPARM MAXHVB 175 Comments: A transition to Operate and back to HVLOW is required in order to change the maximum HV levels to 178 (Segment A) and 175 (Segment B). ------------------------------------------------------------------------------------------------------------------------------------ 2 DARK S/C DATA NONE 1 465 S SAA CONTOUR 31; SPEC COM INSTR ELHLTHVF; AFTER BY 4835 S; NEW ALIGNMENT; QASISTATES COS SI OPERATE OPERATE; QASISTATES COS FUV HVLOW HVNOM; QASISTATES COS NUV HVSAA HVSAA; QESIPARM ENDCTSA 178; QESIPARM ENDCTSB 175 Comments: Increase the HV level to 178 (Segment A) and 175 (Segment B). Includes a 1 hour CARD wait. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ DARK 1 S/C DATA NONE none none none none 1 N/A DARK 2 S/C DATA NONE none none none none 1 N/A 12432( 3) - 23-Nov-2010 15:22:00 - [ 9] Summary Form for Proposal 12432 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures BOA, DEF, NONE, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV, S/C ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, ACQ/SEARCH, DATA, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=125, BUFFER-TIME=1330, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, SCAN-SIZE=2, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER DK BY 0 Orbits TO 2 Orbits, AFTER DN BY 1 Orbits TO 2 D, AFTER HV BY 0 Orbits TO 1 Orbits, AFTER UP BY 0 Orbits TO 2 Orbits, AFTER BY 4835 S, NEW ALIGNMENT, PARALLEL, QASISTATES COS FUV BOOT HVLOW, QASISTATES COS FUV HVLOW HVLOW, QASISTATES COS FUV HVLOW HVNOM, QASISTATES COS NUV HVSAA HVSAA, QASISTATES COS SI OPERATE OPERATE, QESIPARM ENDCTSA 178, QESIPARM ENDCTSB 175, QESIPARM MAXHVA 178, QESIPARM MAXHVB 175, SAA CONTOUR 31, SPEC COM INSTR ELHLTHVF, SPEC COM INSTR ELSETHVMAX ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements DEF, G160M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names DARK, WD1057+719 ------------------------------------------------------------------------------------------------------------------------------------