6937( 7) - 08/29/96 15:31 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6937 Version: 7 Check-in Date: 29-Aug-1996 16:29:07 1.Proposal Title: WFPC2 Cycle 6 CTE Calibration ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle CAL/WF2 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: MASSIMO STIAVELLI SPACE TELESCOPE SCIENCE INSTITUTE ------------------------------------------------------------------------------------ 6. Abstract This program will (1) test whether the exposure time dependence of the photometric calibration is due to CTE (long vs. short exposure problem); (2) refine flux and background-level dependent aperture corrections. ------------------------------------------------------------------------------------ Observations Description ------------------------ The globular cluster NGC2419 will be observed through F555W with a combination of exposure times (between 5 and 1400s) and preflash levels (0 to 500e). Analysis of cycle 5 CTE calibration (proposal 6192) suggests that magnitude errors due to charge transfer effects are greatly reduced (if not entirely eliminated) at background levels of 160e- or greater. CTE effects have been proposed as the solution to reported differences in the magnitudes of stars measured on frames with short exposures vs. long exposures. If CTE is the cause, then the differences should disappear with preflash. We will reobserve the cluster NGC2419 with and without preflash to test this hypothesis. This dataset will also provide a large number of stars with which to refine existing measurements of the effects of CTE on the wings of the PSF. A range of preflash levels will be explored at the 60 sec exposure time. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- This program will require 2 orbits (now it really does). ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6937( 7) - 08/29/96 15:31 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2419 STELLAR CLUSTER, RA = 7H 38M 6.85S +/- 0.1S,DEC = 2000 V = 10.2 GLOBULAR CLUSTER +38D 51' 55.4" +/- 1",PLATE- ID=01H9 6937( 7) - 08/29/96 15:31 - [ 2] Visit: 01 Visit Requirements: ORIENT 259.27D to 279.27D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 INTFLAT WFPC2 IMAGE PC1-FIX F502N READ=NO,BLADE=A 1 16 S SEQ 10-12 NON-INT Comments: preflash=80e ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC2419 WFPC2 IMAGE PC1-FIX F555W 1 60 S MAX DUR; MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ 24 NGC2419 WFPC2 IMAGE PC1-FIX F555W 1 60 S MAX DUR; MIN DUR Comments: no preflash ------------------------------------------------------------------------------------------------------------------------------------ 30 INTFLAT WFPC2 IMAGE PC1-FIX F502N READ=NO,BLADE=A 1 30 S SEQ 30-32 NON-INT Comments: preflash=160e ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC2419 WFPC2 IMAGE PC1-FIX F555W 1 60 S MAX DUR; MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ 34 INTFLAT WFPC2 IMAGE PC1-FIX F502N READ=NO,BLADE=A 1 30 S SEQ 34-36 NON-INT Comments: preflash=160e ------------------------------------------------------------------------------------------------------------------------------------ 36 NGC2419 WFPC2 IMAGE PC1-FIX F555W 1 60 S MAX DUR; MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ 60 INTFLAT WFPC2 IMAGE PC1-FIX F502N READ=NO,BLADE=A 1 45 S SEQ 60-62 NON-INT Comments: preflash=250e ------------------------------------------------------------------------------------------------------------------------------------ 62 NGC2419 WFPC2 IMAGE PC1-FIX F555W 1 60 S MAX DUR; MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ 70 INTFLAT WFPC2 IMAGE PC1-FIX F502N READ=NO,BLADE=A 1 30 S SEQ 70-72 NON-INT Comments: preflash=160e ------------------------------------------------------------------------------------------------------------------------------------ 72 NGC2419 WFPC2 IMAGE PC1-FIX F555W 1 60 S MAX DUR; MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ 78 NGC2419 WFPC2 IMAGE PC1-FIX F555W 1 60 S MAX DUR; MIN DUR Comments: no preflash ------------------------------------------------------------------------------------------------------------------------------------ 90 INTFLAT WFPC2 IMAGE PC1-FIX F502N READ=NO,BLADE=A 1 30 S SEQ 90-92 NON-INT Comments: preflash=160e ------------------------------------------------------------------------------------------------------------------------------------ 92 NGC2419 WFPC2 IMAGE PC1-FIX F555W CR-SPLIT=NO 1 1400 S MAX DUR; MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ 6937( 7) - 08/29/96 15:31 - [ 3] Summary Form for Proposal 6937 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters READ=NO BLADE=A CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category CAL/WF2 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 259.27D to 279.27D SEQ 10-12 NON-INT MAX DUR; MIN DUR SEQ 30-32 NON-INT SEQ 34-36 NON-INT SEQ 60-62 NON-INT SEQ 70-72 NON-INT SEQ 90-92 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502N F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names INTFLAT NGC2419 ------------------------------------------------------------------------------------------------------------------------------------