The list of Investigators does not match the STScI records for this program. FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser 0 ----- Attempting Submission 1 (Fri Aug 01 18:22:11 GMT 2025) ----- All errors are expected and not an issue. The standard astrometric catalog in the field of globular cluster Omega Cen has been used to examine the geometric distortion of WFC3 UVIS as function of wavelength in multi-cycle calibration programs over last 12 years of WFC3 on HST board. All observations from these programs have been reduced and provided the multi-wavelength geometric distortion in UVIS detector. The derived geometric distortion coefficients implemented in the IDCTAB format are used in the HST pipe-line to correct for a ~7% distortion in WFC3/UVIS images down to <1%. Additional to multi-wavelength WFC3 geometric distortion, all observations of Omega Cen taken through F606W UVIS filters during the last 12 years (all together 13 epochs) were used to look for time dependency of UVIS and IR geometric distortion and the effect of the scale change due to the thermal breathing. The results of the stability WFC3 geometric distortion published in WFC3-ISR-2015-02 (Kozhurina-Platais & Anderson, 2015), WFC3-ISR-2019-09 (Martlin, Kozhurina-Platais), have shown that the UVIS geometric distortion is stable over 10 years on-orbit within 0.05 pixels or 2 mas in IR. A more recent study, WFC3 ISR 2024-15 (O'Connor et. al., 2024), finds small linear temporal changes in the UVIS scale and skew terms (less than 0.2 pixels in 13 years) which are generally dominated by intrinsic scatter (up to 0.3 pixels). Concurrently, a larger filter-dependent offset in the scale term is observed, with a maximum difference of 0.3 pixels between F275W and F814W images at all epochs. A small rotation offset to Gaia of 0.003 +/- 0.004 degrees is measured from 2009 to mid-2017, after which the offsets are as large as 0.01 degrees, with a large scatter. Finally, the shift term is seen to evolve at about 0.2 pix/yr in X and -0.3 pix/yr in Y, though these changes are small compared to the uncertainty in pointing within any given observation, and the shift term is dominated by sources of uncertainty outside of the geometric distortion calibration. The purpose of this calibration proposal is to continue the monitor of the stability of the WFC3 geometric distortion over time. The observations of Omega Cen through the UVIS F606W filter will be used to derive the skew and scale terms of the geometric distortion and look for any secular changes over time. In addition, several UVIS filters have been appended for the purposes of generating new PSF models for the community. The observation of Omega Cen through F606W is used as a standard filter in UVIS. They are observed with the same pointing but with different roll-angle of the OTA at a single epoch in either July/August 2026 at an orient of ~126 degrees or in Jan -April 2027 at an orient of ~290 degrees. The 3 exposures in UVIS have steps of roll-angles -1.5, 0, +1.5 degrees requiring 3 orbits. To maintain accurate pointing control, 2-guide star acquisitions are used. If suitable guide stars can be found, the same pair of guide stars are used for all exposures. In this cycle, similiar to Cycle 32, additional UVIS filters are added for the purposes of building additional PSF models, based on usage statistics in GO science programs. ---Calibration Goals--- The geometric distortion of WFC3 in 13 UVIS and 8 IR filters were calibrated using the standard astrometric catalog of Omega Cen (Anderson & van der Marel, 2010). A set of updated distortions were obtained for 20 UVIS filters using the same standard astrometric catalog of Omega Cen (Kozhurina-Platais, WFC3-ISR-2014-12; Martlin et al. WFC3-ISR-2018-11). The goal of this proposal is to monitor the geometric distortion of the UVIS detector. The skew parameter in the ACS/WFC case, is changing with time in the level of 40 mas over 15 years on board of HST. The skew parameter is the non-perpendicularity of coordinate axes and is the major parameter in the geometric distortion model. 0 false false false RESTRICTED CALIBRATION ASTROMETRIC SPATIAL DISTORTION TEST This is the same target (and coordinates) as used in CAL/WFC3 11911, UVIS L-Flats and Geometric Distortion and in other multi-cycles calibration proposals J2000 1754072347150 The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17973 :visit-id "01" :proposal-version -1 :trans-version "20250624" :date "01-Aug-2025 14:19:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732496 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17973 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17973 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2594 :al-overhead-at-end 119 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3011 :pcs-gap 0 ) true 1 0 1754072347885 The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17973 :visit-id "02" :proposal-version -1 :trans-version "20250624" :date "01-Aug-2025 14:19:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732496 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17973 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17973 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2588 :al-overhead-at-end 119 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3011 :pcs-gap 0 ) true 1 0 1754072348581 The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17973 :visit-id "03" :proposal-version -1 :trans-version "20250624" :date "01-Aug-2025 14:19:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1732496 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17973 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17973 :visit-id "03" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2591 :al-overhead-at-end 119 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3011 :pcs-gap 0 ) true 1 0