0 Assigned ID: 7151 ----- Attempting Submission 1 (Wed Apr 15 15:56:02 GMT 2026) ----- HST Phase I Proposal 7151 successfully submitted. Receipt: # 7151-1 ----- Attempting Submission 2 (Thu Apr 16 17:01:43 GMT 2026) ----- Initial submission. 1881027430 ----- Attempting Submission 1 (Mon Aug 10 18:37:55 GMT 2026) ----- From Earth to brown dwarfs, clouds fundamentally shape the visual appearance, outgoing thermal emission, atmospheric circulation, and energy balance of substellar objects. A key piece of our understanding of these clouds is the transition from the cloudy atmospheres of hot Jupiters to the relatively cloud-free atmospheres of ultra-hot Jupiters. This transition depends on a complex interplay between circulation, chemistry, and microphysics and it is not clear from models exactly at what equilibrium temperature this transition should occur. NUV-Optical transmission spectra of planets in this regime suggest clouds dissipate and metals are evaporated into the gas phase somewhere between 2050 and 2250 K. Here, we propose for observations with WFC3/UVIS/G280 (0.2-0.8 um) of three planets between these temperatures to identify silicate cloud precursors (Mg, Fe, Si species) in the gas phase through their enormous NUV absorption. KELT-18b (2085 K), HD 202772 Ab (2130 K), and WASP-82b (2190 K) will trace the cloudy-to-clear transition to a precision of ~50 K, enabling a stringent test of 1D and 3D models of cloud formation. We will further explore whether the transition is discrete or gradual by comparing to nine previously observed planets. Properly understanding the conditions under which clouds begin to form is vital to understanding observed spectra across the substellar domain. Further, quantifying elemental rainout is necessary for accurate atmospheric composition measurements, with critical consequences for accurate planet formation inferences. We are using WFC3/UVIS G280 to obtain spectroscopic time series of exoplanet transit events. Two transits each of three planets will be observed. Our observations spend 1-2 orbits measuring the pre-transit baseline, 2-3 orbits measuring the transit depth, and 1-2 orbits measuring the post-transit baseline. All observations are phase constrained to be around transit events. We include a reference image for calibration to determine the location of the zeroth order trace on the detector, necessary for the wavelength solution. All observations use a custom subarray to optimize read-out times for sufficient duty cycle for our time-series observations. All observations use POSARGS to place the target and subarray on chip 2. Bias images are taken at the end of the visit because of the custom subarray. Observations of HD 202772 Ab are orient constrained to keep a binary compaion ~>=1" resolved in the cross-dispersion direction. Lothringer is an expert in the observation and modeling of exoplanet atmospheres, especially with respect to hot and ultra-hot Jupiters. He is the PI for several HST and JWST programs and the co-I of many more, including investigations with WFC3-UVIS/G280. Sing is an expert in the observation and modeling of exoplanet atmospheres, leading several large HST and JWST programs. Mullens is an expert in the modeling of exoplanet atmospheres, especially with respect to clouds in gas giant planets. Alderson is an expert in the observation of exoplanet atmospheres with extensive experience with both HST and JWST. Boehm is an expert in the observation of exoplanet atmospheres, including observations with WFC3-UVIS/G280. Corrales is an expert in high-energy astronomy, including the observation of exoplanet atmospheres at UV and X-Ray wavelengths. Frazier is an expert in the observation of exoplanet atmospheres, especially at UV and X-Ray wavelengths. Dos Santos is an expert in the observation and modeling of exoplanet atmospheres, especially the upper atmosphere of planets and their mass loss. Ramos Rosado is an expert in the observation of exoplanet atmospheres, especially at UV wavelengths. Alam is an expert in the observation of exoplanet atmospheres, with particular experience with WFC3-UVIS/G280 as an instrument scientist. Wakeford is an expert in the observation of exoplanet atmospheres and is leading a large WFC3-UVIS/G280 survey. Komacek is an expert in the modeling of exoplanet atmospheres with 3D GCMs, especially in the ultra-hot Jupiter regime. Fromont is an expert in the modeling of exoplanet atmospheres with 3D GCMs, including investigations of cloud microphysics. Bennett is an expert in the observation of exoplanet atmospheres and stars, including investigations with WFC3-UVIS/G280. Exoplanets and Exoplanet Formation 6 false true false false false false false AVAILABLE STAR EXTRA-SOLAR PLANET EXTRA-SOLAR PLANETARY SYSTEM F3-F9 This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. J2000 J2000 STAR EXTRA-SOLAR PLANET EXTRA-SOLAR PLANETARY SYSTEM F3-F9 This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. BD+01-828 J2000 J2000 STAR EXTRA-SOLAR PLANET EXTRA-SOLAR PLANETARY SYSTEM F3-F9 This object was generated by the targetselector and retrieved from the SIMBAD database. SIMBAD listed proper motion for this target. When retrieving targets with PM from SIMBAD, APT requests the coordinates be calculated with an epoch of the year 2000. Do not modify this epoch. Always review coordinates using the Target Confirmation tool, which graphically displays the PM. BD+60-1538 J2000 J2000 WFC3/UVIS Spectroscopic No No G280 WFC3/UVIS Spectroscopic No No G280 WFC3/UVIS Spectroscopic No No G280 WFC3/UVIS Spectroscopic No No G280 WFC3/UVIS Spectroscopic No No G280 WFC3/UVIS Spectroscopic No No G280 1786386177712 The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. /private/var/folders/mv/w837twcj1x15d56059x6tb640005r5/T/OPVisit15002178402816701824.xml The optional parameters SIZEAXIS1=2250 and SIZEAXIS2=300 are used for all exposures to minimize the read out time and optimize the duty cycle. This is fine for the data that needs to be obtained because the spectum will occupy only a narrow swath of pixel rows within the field. This also requires the use of optional parameters CENTERAXIS1 and CENTERAXIS2 in order to "steer" the location of the subarray readout so that it is centered on the target spectrum. We hardwire CENTERAXIS1=2136 and CENTERAXIS2=1216, which is intended to put the vertical center of the subarray on the zeroth order of the target spectrum. Chip 2 biases are taken at the end of the visit because the grism exposures use custom subarrays, which will not have matching biases from the WFC3 bias calibration program. For each visit we have phase constraints around the event of the planetary transit, both the orbital period of the planet and the phasing needed are placed on the target acq exposure. Using Jofre et al. 2025 orbital parameters. Transit events agree to within a few minutes of other ephemerides. To avoid any contamination by several dim, nearby stars, we have placed Orient Ranges for the observations to reach our science goals. From discovery paper AO imaging of the binary system in Wang et al. 2019 (Fig. 2), we measure the companion star to be 29 degrees north of west and 1.3" separated. To keep the star at least 1" (25 pixels) away from the target star in the non-dispersion direction, we place orient constraints 40 degrees wide on either side (1.3*np.cos(40.0*np.pi/180) ~ 1.0) of the 59 degree V3PA that maximally separates the objects in the non-dispersion direction. This results in several transit opportunities for the UVIS observations in Spring/Summer 2027. (Tic-Visit :proposal-id 18381 :visit-id "01" :proposal-version -1 :trans-version "20260618" :date "10-Aug-2026 14:22:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2467616 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18381 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18381 :visit-id "01" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2642 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "01" :orbit-number 2 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "01" :orbit-number 3 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "01" :orbit-number 4 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "01" :orbit-number 5 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "01" :orbit-number 6 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 746 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) true 6 0 For the reference image ("filter acq"), saturation in 0.87 seconds. 0.5 seconds gives SNR of >400. The nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2, at an approximate XY position of (2048,1024). CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the target spectrum, which will be displaced from the direct image of the target, in agreement with programs 16039, 16695, and 17082. We match the subarray size of the science exposures. We use FLASH=16 to meet the nominal count level. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. We set up the bias frames based on previously sucessful program 11934, 16039, and 16086 and are using the same Aperture and subarray size and position as the observations for direct calibration. 1786133499863 The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. /private/var/folders/mv/w837twcj1x15d56059x6tb640005r5/T/OPVisit6695416859664132804.xml The optional parameters SIZEAXIS1=2250 and SIZEAXIS2=300 are used for all exposures to minimize the read out time and optimize the duty cycle. This is fine for the data that needs to be obtained because the spectum will occupy only a narrow swath of pixel rows within the field. This also requires the use of optional parameters CENTERAXIS1 and CENTERAXIS2 in order to "steer" the location of the subarray readout so that it is centered on the target spectrum. We hardwire CENTERAXIS1=2136 and CENTERAXIS2=1216, which is intended to put the vertical center of the subarray on the zeroth order of the target spectrum. Chip 2 biases are taken at the end of the visit because the grism exposures use custom subarrays, which will not have matching biases from the WFC3 bias calibration program. For each visit we have phase constraints around the event of the planetary transit, both the orbital period of the planet and the phasing needed are placed on the target acq exposure. Using Jofre et al. 2025 orbital parameters. Transit events agree to within a few minutes of other ephemerides. To avoid any contamination by several dim, nearby stars, we have placed Orient Ranges for the observations to reach our science goals. From discovery paper AO imaging of the binary system in Wang et al. 2019 (Fig. 2), we measure the companion star to be 29 degrees north of west and 1.3" separated. To keep the star at least 1" (25 pixels) away from the target star in the non-dispersion direction, we place orient constraints 40 degrees wide on either side (1.3*np.cos(40.0*np.pi/180) ~ 1.0) of the 59 degree V3PA that maximally separates the objects in the non-dispersion direction. This results in several transit opportunities for the UVIS observations in Spring/Summer 2027. (Tic-Visit :proposal-id 18381 :visit-id "02" :proposal-version -1 :trans-version "20260618" :date "07-Aug-2026 16:11:38.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2467616 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18381 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18381 :visit-id "02" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2642 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "02" :orbit-number 2 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "02" :orbit-number 3 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "02" :orbit-number 4 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "02" :orbit-number 5 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 478 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "02" :orbit-number 6 :pcs-time 301 :si-vis-utilization 2647 :al-overhead-at-end 47 :internal-dur-at-end 746 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2983 :pcs-gap 0 ) true 6 0 For the reference image ("filter acq"), saturation in 0.87 seconds. 0.5 seconds gives SNR of >400. The nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2, at an approximate XY position of (2048,1024). CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the target spectrum, which will be displaced from the direct image of the target, in agreement with programs 16039, 16695, and 17082. We match the subarray size of the science exposures. We use FLASH=16 to meet the nominal count level. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~55.5K, which is 87% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 16 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. We set up the bias frames based on previously sucessful program 11934, 16039, and 16086 and are using the same Aperture and subarray size and position as the observations for direct calibration. 1786135538903 The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. /private/var/folders/mv/w837twcj1x15d56059x6tb640005r5/T/OPVisit16203128786046054023.xml The optional parameters SIZEAXIS1=2250 and SIZEAXIS2=300 are used for all exposures to minimize the read out time and optimize the duty cycle. This is fine for the data that needs to be obtained because the spectum will occupy only a narrow swath of pixel rows within the field. This also requires the use of optional parameters CENTERAXIS1 and CENTERAXIS2 in order to "steer" the location of the subarray readout so that it is centered on the target spectrum. We hardwire CENTERAXIS1=2136 and CENTERAXIS2=1216, which is intended to put the vertical center of the subarray on the zeroth order of the target spectrum. Chip 2 biases are taken at the end of the visit because the grism exposures use custom subarrays, which will not have matching biases from the WFC3 bias calibration program. For each visit we have phase constraints around the event of the planetary transit, both the orbital period of the planet and the phasing needed are placed on the target acq exposure. Many visit opportunities exist throughout the year. Using Kokori et al. 2023 orbital parameters. Recent (non-candidate) solutions all agree to within 15 minutes. (Tic-Visit :proposal-id 18381 :visit-id "03" :proposal-version -1 :trans-version "20260618" :date "07-Aug-2026 16:45:37.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1604640 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18381 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18381 :visit-id "03" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2671 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "03" :orbit-number 2 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "03" :orbit-number 3 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "03" :orbit-number 4 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "03" :orbit-number 5 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "03" :orbit-number 6 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 881 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 6 0 For the reference image ("filter acq"), saturation in 3.95 seconds. 2 seconds gives SNR of >400. The nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2, at an approximate XY position of (2048,1024). CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the target spectrum, which will be displaced from the direct image of the target, in agreement with programs 16039, 16695, and 17082. We match the subarray size of the science exposures. We use FLASH=20 to meet the nominal count level. With exposure time of 60 second, we remain below 83% saturation (w/ saturation at 76.44 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. We set up the bias frames based on previously sucessful program 11934, 16039, and 16086 and are using the same Aperture and subarray size and position as the observations for direct calibration. 1786135544346 The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. /private/var/folders/mv/w837twcj1x15d56059x6tb640005r5/T/OPVisit13165752999842703339.xml The optional parameters SIZEAXIS1=2250 and SIZEAXIS2=300 are used for all exposures to minimize the read out time and optimize the duty cycle. This is fine for the data that needs to be obtained because the spectum will occupy only a narrow swath of pixel rows within the field. This also requires the use of optional parameters CENTERAXIS1 and CENTERAXIS2 in order to "steer" the location of the subarray readout so that it is centered on the target spectrum. We hardwire CENTERAXIS1=2136 and CENTERAXIS2=1216, which is intended to put the vertical center of the subarray on the zeroth order of the target spectrum. Chip 2 biases are taken at the end of the visit because the grism exposures use custom subarrays, which will not have matching biases from the WFC3 bias calibration program. For each visit we have phase constraints around the event of the planetary transit, both the orbital period of the planet and the phasing needed are placed on the target acq exposure. Many visit opportunities exist throughout the year. Using Kokori et al. 2023 orbital parameters. Recent (non-candidate) solutions all agree to within 15 minutes. (Tic-Visit :proposal-id 18381 :visit-id "04" :proposal-version -1 :trans-version "20260618" :date "07-Aug-2026 16:45:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1604640 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18381 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18381 :visit-id "04" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2671 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "04" :orbit-number 2 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "04" :orbit-number 3 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "04" :orbit-number 4 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "04" :orbit-number 5 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "04" :orbit-number 6 :pcs-time 301 :si-vis-utilization 2598 :al-overhead-at-end 41 :internal-dur-at-end 881 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 6 0 For the reference image ("filter acq"), saturation in 3.95 seconds. 2 seconds gives SNR of >400. The nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2, at an approximate XY position of (2048,1024). CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the target spectrum, which will be displaced from the direct image of the target, in agreement with programs 16039, 16695, and 17082. We match the subarray size of the science exposures. We use FLASH=20 to meet the nominal count level. With exposure time of 60 second, we remain below 83% saturation (w/ saturation at 76.44 seconds)(with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 83% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 14 second, we remain below 87% saturation (w/ saturation at 16.88 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52.6K, which is 82.8% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 14 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. We set up the bias frames based on previously sucessful program 11934, 16039, and 16086 and are using the same Aperture and subarray size and position as the observations for direct calibration. 1786385064039 The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. /private/var/folders/mv/w837twcj1x15d56059x6tb640005r5/T/OPVisit11410074661158973753.xml The optional parameters SIZEAXIS1=2250 and SIZEAXIS2=300 are used for all exposures to minimize the read out time and optimize the duty cycle. This is fine for the data that needs to be obtained because the spectum will occupy only a narrow swath of pixel rows within the field. This also requires the use of optional parameters CENTERAXIS1 and CENTERAXIS2 in order to "steer" the location of the subarray readout so that it is centered on the target spectrum. We hardwire CENTERAXIS1=2136 and CENTERAXIS2=1216, which is intended to put the vertical center of the subarray on the zeroth order of the target spectrum. Chip 2 biases are taken at the end of the visit because the grism exposures use custom subarrays, which will not have matching biases from the WFC3 bias calibration program. For each visit we have phase constraints around the event of the planetary transit, both the orbital period of the planet and the phasing needed are placed on the target acq exposure. Many visit opportunities exist throughout the year. Using Kokori et al. 2023 ephemeris, which agrees with all others to within a a couple minutes. (Tic-Visit :proposal-id 18381 :visit-id "05" :proposal-version -1 :trans-version "20260618" :date "10-Aug-2026 14:04:22.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1526064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18381 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18381 :visit-id "05" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2667 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "05" :orbit-number 2 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "05" :orbit-number 3 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "05" :orbit-number 4 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "05" :orbit-number 5 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "05" :orbit-number 6 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 893 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) true 6 0 For the reference image ("filter acq"), saturation in 4.46 seconds. 2 seconds gives SNR of >380. The nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2, at an approximate XY position of (2048,1024). CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the target spectrum, which will be displaced from the direct image of the target, in agreement with programs 16039, 16695, and 17082. We match the subarray size of the science exposures. We use FLASH=20 to meet the nominal count level. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 87% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. We set up the bias frames based on previously sucessful program 11934, 16039, and 16086 and are using the same Aperture and subarray size and position as the observations for direct calibration. 1786385069081 The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. /private/var/folders/mv/w837twcj1x15d56059x6tb640005r5/T/OPVisit13005556407714723678.xml The optional parameters SIZEAXIS1=2250 and SIZEAXIS2=300 are used for all exposures to minimize the read out time and optimize the duty cycle. This is fine for the data that needs to be obtained because the spectum will occupy only a narrow swath of pixel rows within the field. This also requires the use of optional parameters CENTERAXIS1 and CENTERAXIS2 in order to "steer" the location of the subarray readout so that it is centered on the target spectrum. We hardwire CENTERAXIS1=2136 and CENTERAXIS2=1216, which is intended to put the vertical center of the subarray on the zeroth order of the target spectrum. Chip 2 biases are taken at the end of the visit because the grism exposures use custom subarrays, which will not have matching biases from the WFC3 bias calibration program. For each visit we have phase constraints around the event of the planetary transit, both the orbital period of the planet and the phasing needed are placed on the target acq exposure. Many visit opportunities exist throughout the year. Using Kokori et al. 2023 ephemeris, which agrees with all others to within a a couple minutes. (Tic-Visit :proposal-id 18381 :visit-id "06" :proposal-version -1 :trans-version "20260618" :date "10-Aug-2026 14:04:27.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 6 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1526064 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18381 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18381 :visit-id "06" :orbit-number 1 :pcs-time 301 :si-vis-utilization 2667 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "06" :orbit-number 2 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "06" :orbit-number 3 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "06" :orbit-number 4 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "06" :orbit-number 5 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18381 :visit-id "06" :orbit-number 6 :pcs-time 301 :si-vis-utilization 2720 :al-overhead-at-end 46 :internal-dur-at-end 893 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3044 :pcs-gap 0 ) true 6 0 For the reference image ("filter acq"), saturation in 4.46 seconds. 2 seconds gives SNR of >380. The nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2, at an approximate XY position of (2048,1024). CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the target spectrum, which will be displaced from the direct image of the target, in agreement with programs 16039, 16695, and 17082. We match the subarray size of the science exposures. We use FLASH=20 to meet the nominal count level. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 83% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. With exposure time of 66 second, we remain below 87% saturation (w/ saturation at 86.4 seconds) (with a maximum SNR of about 700 at about 4000 Angstrom). Our brightest pixel is expected to be ~52K, which is ~82% of the lowest full-well depth from ISR WFC3 2025-06. We also add a FLASH of 13 to improve CTE. Combined with the high flux from the object, we're not too worried about CTE, but FLASH could be increased at the expense of fewer exposures in the time series... Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=300 are used to minimize readout times, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574, 15288, 16086, 17082. We set up the bias frames based on previously sucessful program 11934, 16039, and 16086 and are using the same Aperture and subarray size and position as the observations for direct calibration.