The list of Investigators does not match the STScI records for this program. Added 3 members of the WFC3 team as Co-I's, and constructed the 5 visits for the observations. -503464186 ----- Attempting Submission 1 (Fri Nov 19 22:30:07 GMT 2021) ----- Added members of the WFC3 photometric calibration group as Co-I's for backup. WFC3/IR Time-Dependent Sensitivity in Staring Mode (Clusters) The IR grism flux monitor shows a sensitivity loss of 0.12+/-0.01%/yr in G102 and 0.06+/-0.01%/yr in G141. Observations of flux standards in the IR filters, however, show no evidence of any loss over time, but the repeatability is limited by systematic errors of +/- 1%. Scanned observations of M35 from 2015-2020 show marginal losses of 0.024+/- 0.008%/yr in F140W, but these data show a large scatter which may be related to detector preconditioning. Cluster observations allow for the measurement of many more stars, and photometry of the core Omega-Cen used for distortion monitoring suggests losses of 0.23 +/- 0.03%/yr in F160W, but crowding may play an effect on the results. Recent observations of a less dense stellar field in M4 in F110W suggest losses of 0.13 +/- 0.02%/yr (first images only) and 0.20 +/- 0.03%/yr (all images), but these consist of only 4 visits. We propose continued monitoring of M4 at a ~6 month cadence. Two additional clusters are requested: the NGC104 field 6' from the core with F160W data from 2009-2013 and an Omega-Cen field 17' from the core with F110W & F160W images from 2016-2018, both of which mimic the observation strategy from the respective preceeding epochs, to eliminate systematics from differing observing modes. In general, these observations copy the targets, sample sequences, NSamps, and orbit structure of previously obtained WFC3/IR observations, as this yields the fewest systematics when attempting to measure sensitivity losses over time. We propose two visits of WFC3/IR observations of M4. Both visits will be executed with the same exposure parameters, but will be scheduled approximately 6 months apart (Summer/Fall 2022 and Winter/Spring 2023), to best sample the time dependence of the sensitivity withtin the window in which the target is visible. Each visit will be composed of 4 exposures, the first two in F110W and the latter two in F160W. The F110W images will use 14 samples with the SPARS50 sample sequence to match those taken in 16512. To mitigate persistence, POSTARGS of 2.5 arcseconds in X and Y will be used between exposures, to match the observations of 16512. The visits are constrained to be 180 degrees apart, to be able to discern flat field effects. The orients of visits will match the respective visits from 16512 to separate flat field effects from sensitivity loss. The target coordinates for Visit 01 have been adjusted from 16512 to more closely match the field of view in Visit 02 as well as prior observations. The two visit of WFC3/IR observations of Omega Centauri are configured to match the IR obsevations of 14662 (Visits 31 and 39 for F110W and F160W, respectively). In this case however, WFC3/IR is used as the primary instrument (as opposed to 14662 where ACS/WFC was the primary and WFC3/IR was the parallel). The roll angle was also constrained to be within 2.5 degrees of the visits from 14662, to eliminate flat field effects. The target positions and postargs were adjusted accordingly to account for the switch from parallel to prime. Visit 04 is constrained to occur at least 3 days after Visit 03 to prevent these two visits from being scheduled consecutively (which would introduce persistence). The visit of WFC3/IR observations of 47 Tuc was configued to match 13563 Visit 01. The roll was not constrained, as prervious observations were taken with a large range of roll angles. The last exposure in the visit was changed (relative to 13563 Visit 01) from a dark to another F160W exposure, as we will not be performing analysis on the darks, and thus the orbit time can be better spent taking one more external exposure, without changing the observational configuration for the previous exposures. The last exposure is also dithered by approximately 40 pixels to mitigate persistence. 0 false false RESTRICTED STELLAR CLUSTER GLOBULAR CLUSTER J2000 STELLAR CLUSTER GLOBULAR CLUSTER J2000 STELLAR CLUSTER GLOBULAR CLUSTER J2000 J2000 CALIBRATION DETECTOR LINEARITY TEST NGC104 J2000 The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /private/var/folders/2b/788l6xx92z9cqlwly6dwfb540001g1/T/OPVisit18280234316138178820.xml (Tic-Visit :proposal-id 16864 :visit-id "01" :proposal-version -1 :trans-version "20210514" :date "19-Nov-2021 17:25:42.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1009712 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16864 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16864 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 481 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /private/var/folders/2b/788l6xx92z9cqlwly6dwfb540001g1/T/OPVisit10230466370094923315.xml (Tic-Visit :proposal-id 16864 :visit-id "02" :proposal-version -1 :trans-version "20210514" :date "19-Nov-2021 17:25:42.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1009712 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16864 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16864 :visit-id "02" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 481 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3165 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([04 After 03 by 3.0 to 100.0 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /private/var/folders/2b/788l6xx92z9cqlwly6dwfb540001g1/T/OPVisit16608488461267758721.xml (Tic-Visit :proposal-id 16864 :visit-id "03" :proposal-version -1 :trans-version "20210514" :date "19-Nov-2021 17:25:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 765984 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16864 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16864 :visit-id "03" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2698 :al-overhead-at-end 0 :internal-dur-at-end 462 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3134 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([04 After 03 by 3.0 to 100.0 days]) The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /private/var/folders/2b/788l6xx92z9cqlwly6dwfb540001g1/T/OPVisit11377989482620760511.xml (Tic-Visit :proposal-id 16864 :visit-id "04" :proposal-version -1 :trans-version "20210514" :date "19-Nov-2021 17:25:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 765984 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16864 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16864 :visit-id "04" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2698 :al-overhead-at-end 0 :internal-dur-at-end 462 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3134 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. /Users/vbajaj/Downloads/OP-cache/16864_vb-v05.xml (Tic-Visit :proposal-id 16864 :visit-id "05" :proposal-version -1 :trans-version "20210514" :date "19-Nov-2021 17:22:15.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1706064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16864 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16864 :visit-id "05" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2719 :al-overhead-at-end 0 :internal-dur-at-end 728 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3525 :pcs-gap 0 ) true 1 0 Designed to just saturate V=20 stars.