The list of Investigators does not match the STScI records for this program. The schedulability windows on Visit 02 are tight, please let me know if those will be an issue, as we have some room for modification. The single warning can be negated, as I have added the CoI's from the similar program from last cycle. 1605750644 ----- Attempting Submission 1 (Tue Nov 22 01:00:36 GMT 2022) ----- Added usual CoIs from WFC3 team. 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. To continue the monitoring of the WFC3/IR sensitivity loss we observe the clusters M4 and 47Tuc using the same observation strategies in HST programs 16864 and 16512, continuing the monitors for a subset of the clusters observed in those programs. Spefically, we propose a single epoch of M4 (using both F110W and F160W) and two epochs of 47Tuc (using solely F160W). This allows continued measurement of the sensitivity losses from M4, which has multiple epochs of observation since 2020, and will help better constrain the sensitivity losses derived from the 47Tuc measurements, which otherwise only had only a single epoch of observation after 2014. We use the same filters, exposure times, and sample sequences as the corresponding previous observations to minimize any systematic effects caused by using different configurations, and employ the same dithering strategy to obtain consistent detector preconditioning. The 47Tuc observations will be separated by approximately 6 months (180 degree roll), to more evenly sample the temporal change. In general, these observations copy the targets, sample sequences, NSamps, and orbit structure of previously obtained WFC3/IR observations in 16512, as this yields the fewest systematics when attempting to measure sensitivity losses over time. We propose a single M4 Visit to match Visit 01 of 16864, using the same filters, exposure times, sample sequences, dithers, and roll angle. This will help eliminate systematics when comparing the relative photometry. The visit consists of 4 exposures, starting with two F110W and ending with two F160W exposures. The F110W exposures will use the SPARS50 sample sequence with 14 samples. The F160W exposures will only use 13 samples, due to the shorter orbital length (matching 16512). After each exposure POSTARGS of 2.5" will be applied, to mitigate self persistence. The first visit of WFC3/IR observations of 47 Tuc (visit 02) was configued to be similar to 16864 Visit 05, which itself was based on Visit 01 of 13563. As opposed to previous observations, the roll for the first epoch is constrained to be similar to 16964 Visit 05 (previous observations were unconstrained, leading to a mix of roll angles used). The structure of the visit itself is the same as 16864 (which itself differs be the next most recent epoch, from 13563, by changing the last dark to another F160W exposure). As performed in 16864 Visit 05, the last exposure is also dithered by approximately 40 pixels as this help mitigate the effect of self persistence. Visit 03 of this program repeates the observations of Visit02, but rolled at 180 degrees, and will take place approximately 6 months later, to better sample temporal changes in sensitivity. 0 false false RESTRICTED STELLAR CLUSTER GLOBULAR CLUSTER J2000 CALIBRATION DETECTOR LINEARITY TEST NGC104 J2000 1668466948780 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17260 :visit-id "01" :proposal-version -1 :trans-version "20220630" :date "14-Nov-2022 18:02:22.0" :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 17260 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17260 :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 30.3. CASM was run in Phase II mode. 1669069293469 (Tic-Visit :proposal-id 17260 :visit-id "02" :proposal-version -1 :trans-version "20220630" :date "21-Nov-2022 17:21:24.0" :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 17260 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17260 :visit-id "02" :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. The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1669075444833 (Tic-Visit :proposal-id 17260 :visit-id "03" :proposal-version -1 :trans-version "20220630" :date "21-Nov-2022 19:03:59.0" :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 17260 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17260 :visit-id "03" :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 ) false 1 0 Designed to just saturate V=20 stars.