18406( 2) - 13-Aug-2026 16:14:37 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18406 Version: 2 Check-in Time: 13-Aug-2026 16:14:37 STScI Edit Number: 0 Title Measuring Andromeda's Alpha-Element Enrichment in 100,000 Red Giants ------------------------------------------------------------------------------------ Type Cycle GO 34 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. David Moise Nataf University of Iowa Y CoI: Dr. Sarah Loebman University of California - Merced N CoI: Dr. R. Michael Rich University of California - Los Angeles N CoI: Dr. Ricardo Schiavon Liverpool John Moores University N CoI: Dr. Daniel Horta University of Edinburgh, Institute for N Astronomy CoI: Dr. Christian Johnson Space Telescope Science Institute N CoI: Dr. Domenico Nardiello Universita degli Studi di Padova N CoI: Dr. Santi Cassisi INAF - Osservatorio Astronomico d'Abruzzo N CoI: Dr. Gail Zasowski University of Utah N CoI: Dr. Gagandeep Singh Anand Space Telescope Science Institute N CoI: Rachel Pauline University of Iowa N CoI: Ms. MEGAN LOUISE BARRY University of California - Davis N CoI: Michael Richard Hayden University of Oklahoma Norman Campus N CoI: Dr. David Nidever Montana State University - Bozeman N CoI: Rosemary Wyse The Johns Hopkins University N ------------------------------------------------------------------------------------ Abstract The bimodal distribution of stars in the [alpha/Fe] -[Fe/H] plane of the Milky Way is among the most debated signatures in Galactic archaeology, separating an old, alpha-enhanced thick disk from a younger, alpha-poor thin disk. Whether this bimodality is a peculiarity of our Galaxy or a generic feature of large disk galaxies remains unknown. Simulations disagree sharply, and no comparable galaxy has been studied with sufficient sample size and chemical resolution to arbitrate. Andromeda (M31) is the nearest galaxy where this can be resolved observationally. We propose HST imaging in F390W+F606W toward four fields spanning M31's bulge and disk. These sightlines are selected to overlap archival JWST imaging and spectroscopy, and to trace Andromeda's chemical enrichment with galactocentric radius. The F390W filter, situated where iron-peak line blanketing dramatically suppresses stellar flux relative to alpha-element opacity, provides sensitivity to [Fe/H] independently of bulk metallicity, breaking the degeneracy limiting optical or infrared photometry. Combined with archival JWST/NIRCam and HST photometry, fitting the spectral energy distributions will yield joint [Fe/H] and [alpha/Fe] posteriors for ~100, 000 red giants, the largest chemically-resolved stellar sample ever assembled beyond the Milky Way. Spectra from archival JWST/NIRSpec programs provide ~300-star validation samples. As byproducts, the survey yields a precise M31 extinction curve and targeting diagnostics for future campaigns. This method can be applied to a handful of large, nearby galaxies (e.g. M33, NGC 300), and eventually dozens more with the Habitable Worlds Observatory's ultraviolet capabilities. 18406( 2) - 13-Aug-2026 16:14:37 - [ 2] ------------------------------------------------------------------------------------ Observations Description ------------------------ Four fields of Andromeda's disk are observed in primary + parallel. These fields are called (from outer to inner disk) Nidever's window, Mackereth's window, Sanford's window, and M31-BULGE-PHAT-BRICK-01-EAST. The first three fields are named after the PIs that got JWST-GO programs (2609, 2301, 4735) approved toward these fields, where they obtained both NIRCam and NIRSpec data. The fourth field is named after the PHAT brick (PI: Dalcanton) on which it is located, and will be the subject of coordinated JWST observations approved with this program (JWST-GO-12720). For each field, the aim is to align the primary WFC3 observations (F390W and F606W) with the JWST data. There are 10 orbits for each field, of which 8 go to F390W observations, and 2 go to F606W observations. These are in turn split into two subsets, totalling 3 visits and 5 orbits total, where the two subsets are offset by a small shift of 30 arcseconds in each of RA and DEC, and an orient angle shift of between 20 and 180 degrees. That offset and orient angle shift is to help account for detector artefacts such as CTE. The overlap of approximately 70% will produce deeper, more precise imaging in F390W. The parallel observations are taken with ACS. At 10 orbits per field, there are 4 orbits associated with F435W, 4 orbits associated with F625W, and 2 orbits associated with F555W. These were discussed in the proposal as having two uses: legacy value as these are filters that were not imaged with the Panchromatic Hubble Andromeda Treasury, and also to help study the extinction curve in Andromeda. ------------------------------------------------------------------------------------ 18406( 2) - 13-Aug-2026 16:14:37 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 2 MACKERETH-WI GALAXY, DISK RA=00H44M56.0000S, J2000 V = 23 +/- 2 NDOW DEC=+41D45'37.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 1 NIDEVER-WIND GALAXY, DISK RA=00H46M8.5000S, J2000 V = 23 +/- 2 OW DEC=+42D04'7.00" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 SANFORD-WIND GALAXY, DISK RA=00H43M51.0310S, J2000 V = 23 +/- 2 OW DEC=+41D30'37.81" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 M31-BULGE-PH GALAXY, DISK RA=00H43M0.0000S, J2000 V = 23 +/- 2 AT-BRICK-01- DEC=+41D14'24.00" EAST Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 18406( 2) - 13-Aug-2026 16:14:37 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 18406( 2) - 13-Aug-2026 16:14:37 - [ 5] Visit: 01 (M31-BULGE-PHAT-BRICK-01-EAST_Visit1_F390W) Visit Requirements: ORIENT 190D TO 260 D On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S PAR 2 WITH 1 HAT-BRICK-0 S ER (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 2 M31-BULGE-P ACS/WFC ACCUM WFC F435W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 3 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.158, 0.070; HAT-BRICK-0 S ER (2200 S) PAR 4 WITH 3 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 4 M31-BULGE-P ACS/WFC ACCUM WFC F435W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A K-01-EAST M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A K-01-EAST 18406( 2) - 13-Aug-2026 16:14:37 - [ 6] Visit: 02 (M31-BULGE-PHAT-BRICK-01-EAST_Visit2_F390W) Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG -0.06, 0.095; HAT-BRICK-0 S ER (2200 S) PAR 2 WITH 1 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 2 M31-BULGE-P ACS/WFC ACCUM WFC F625W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 3 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.099, 0.165; HAT-BRICK-0 S ER (2200 S) PAR 4 WITH 3 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 4 M31-BULGE-P ACS/WFC ACCUM WFC F625W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A K-01-EAST M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A K-01-EAST 18406( 2) - 13-Aug-2026 16:14:37 - [ 7] Visit: 03 (M31-BULGE-PHAT-BRICK-01-EAST_Visit3_F606W) Visit Requirements: SAME ORIENT AS 01 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S PATTERN 3 1-2; PAR 2 HAT-BRICK-0 S ER (1725 S) WITH 1 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A K-01-EAST S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 8] Visit: 04 (M31-BULGE-PHAT-BRICK-01-EAST_Visit4) Visit Requirements: ORIENT -180D TO -20D FROM 01 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30, -30; PAR 2 HAT-BRICK-0 S ER (2200 S) WITH 1 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 2 M31-BULGE-P ACS/WFC ACCUM WFC F435W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 3 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.158, -29.93; HAT-BRICK-0 S ER (2200 S) PAR 4 WITH 3 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 4 M31-BULGE-P ACS/WFC ACCUM WFC F435W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A K-01-EAST M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A K-01-EAST 18406( 2) - 13-Aug-2026 16:14:37 - [ 9] Visit: 05 (M31-BULGE-PHAT-BRICK-01-EAST_Visit5_F390W) Visit Requirements: SAME ORIENT AS 04 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 29.94, -29.905; HAT-BRICK-0 S ER (2200 S) PAR 2 WITH 1 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 2 M31-BULGE-P ACS/WFC ACCUM WFC F625W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 3 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.099, HAT-BRICK-0 S ER (2200 S) -29.835; PAR 4 WITH 3 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ 4 M31-BULGE-P ACS/WFC ACCUM WFC F625W 2 1100 S HAT-BRICK-0 (2200 S) 1-EAST ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A K-01-EAST M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A K-01-EAST M31-BULGE-PHAT-BRIC 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A K-01-EAST 18406( 2) - 13-Aug-2026 16:14:37 - [ 10] Visit: 06 (M31-BULGE-PHAT-BRICK-01-EAST_Visit6_F606W) Visit Requirements: SAME ORIENT AS 04 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 M31-BULGE-P WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S POS TARG 30, -30; HAT-BRICK-0 S ER (1725 S) PATTERN 3 1-2; PAR 2 1-EAST WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A K-01-EAST S TER M31-BULGE-PHAT-BRIC 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A K-01-EAST S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 11] Visit: 07 (SanfordWindow_Visit1_F390W) Visit Requirements: ORIENT 190D TO 260 D On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S PAR 2 WITH 1 DOW S ER (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.158, 0.070; DOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 12] Visit: 08 (SanfordWindow_Visit2_F390W) Visit Requirements: SAME ORIENT AS 07 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG -0.06, 0.095; DOW S ER (2200 S) PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.099, 0.165; DOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 13] Visit: 09 (SanfordWindow_Visit3_F606W) Visit Requirements: SAME ORIENT AS 07 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S PATTERN 3 1-2; PAR 2 DOW S ER (1725 S) WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 14] Visit: 10 (SanfordWindow_Visit4_F390W) Visit Requirements: ORIENT -180D TO -20D FROM 07 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30, -30; PAR 2 DOW S ER (2200 S) WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.158, -29.93; DOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 15] Visit: 11 (SanfordWindow_Visit5_F390W) Visit Requirements: SAME ORIENT AS 10 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 29.94, -29.905; DOW S ER (2200 S) PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.099, DOW S ER (2200 S) -29.835; PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER SANFORD-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 16] Visit: 12 (SanfordWindow_Visit6_F606W) Visit Requirements: SAME ORIENT AS 10 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SANFORD-WIN WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S POS TARG 30, -30; DOW S ER (1725 S) PATTERN 3 1-2; PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A S TER SANFORD-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 17] Visit: 13 (MackerethWindow_Visit1_F390W) Visit Requirements: ORIENT 190D TO 260 D On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S PAR 2 WITH 1 INDOW S ER (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.158, 0.070; INDOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 18] Visit: 14 (MackerethWindow_Visit2_F390W) Visit Requirements: SAME ORIENT AS 13 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG -0.06, 0.095; INDOW S ER (2200 S) PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.099, 0.165; INDOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 19] Visit: 15 (MackerethWindow_Visit3_F606W) Visit Requirements: SAME ORIENT AS 13 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S PATTERN 3 1-2; PAR 2 INDOW S ER (1725 S) WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 20] Visit: 16 (MackerethWindow_Visit4_F390W) Visit Requirements: ORIENT -180D TO -20D FROM 13 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30, -30; PAR 2 INDOW S ER (2200 S) WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.158, -29.93; INDOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 21] Visit: 17 (MackerethWindow_Visit5_F390W) Visit Requirements: SAME ORIENT AS 22 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 29.94, -29.905; INDOW S ER (2200 S) PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.099, INDOW S ER (2200 S) -29.835; PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER MACKERETH-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 22] Visit: 18 (MackerethWindow_Visit6_F606W) Visit Requirements: SAME ORIENT AS 16 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MACKERETH-W WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S POS TARG 30, -30; INDOW S ER (1725 S) PATTERN 3 1-2; PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A S TER MACKERETH-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 23] Visit: 19 (NideverWindow_Visit1_F390W) Visit Requirements: ORIENT 190D TO 260 D On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S PAR 2 WITH 1 DOW S ER (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.158, 0.070; DOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 24] Visit: 20 (NideverWindow_Visit2_F390W) Visit Requirements: SAME ORIENT AS 19 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG -0.06, 0.095; DOW S ER (2200 S) PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 0.099, 0.165; DOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 25] Visit: 21 (NideverWindow_Visit3_F606W) Visit Requirements: SAME ORIENT AS 19 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S PATTERN 3 1-2; PAR 2 DOW S ER (1725 S) WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 26] Visit: 22 (NideverWindow_Visit4_F390W) Visit Requirements: ORIENT -180D TO -20D FROM 19 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 1 and 2 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30, -30; PAR 2 DOW S ER (2200 S) WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.158, -29.93; DOW S ER (2200 S) PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F435W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F435W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F435W none none 2 none 1 N/A NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F435W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F435W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 27] Visit: 23 (NideverWindow_Visit5_F390W) Visit Requirements: SAME ORIENT AS 10 On Hold Comments: Additional Comments: Each prime+parallel group corresponds to a dither point, this is for dither points 3 and 4 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 29.94, -29.905; DOW S ER (2200 S) PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F390W FLASH=7 2 1100 S POS TARG 30.099, DOW S ER (2200 S) -29.835; PAR 4 WITH 3 ------------------------------------------------------------------------------------------------------------------------------------ 4 ANY ACS/WFC ACCUM WFC F625W 2 1100 S (2200 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F625W none none 1 none 1 N/A ANY 2 ACS/WFC ACCUM WFC F625W none none 2 none 1 N/A NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 1 none 2 N/A S TER NIDEVER-WINDOW 3 WFC3/UVI ACCUM UVIS-CEN F390W none none 2 none 2 N/A S TER ANY 4 ACS/WFC ACCUM WFC F625W none none 1 none 2 N/A ANY 4 ACS/WFC ACCUM WFC F625W none none 2 none 2 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 28] Visit: 24 (NideverWindow_Visit6_F606W) Visit Requirements: SAME ORIENT AS 22 On Hold Comments: Additional Comments: Does three-line in WFC3/F606W and ACS/F555W Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NIDEVER-WIN WFC3/UVI ACCUM UVIS-CENT F606W 1 575 S POS TARG 30, -30; DOW S ER (1725 S) PATTERN 3 1-2; PAR 2 WITH 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY ACS/WFC ACCUM WFC F555W 1 450 S (1350 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 1 none none none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 2 none none none 1 N/A S TER NIDEVER-WINDOW 1 WFC3/UVI ACCUM UVIS-CEN F606W 3 none none none 1 N/A S TER ANY 2 ACS/WFC ACCUM WFC F555W 1 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 2 none none none 1 N/A ANY 2 ACS/WFC ACCUM WFC F555W 3 none none none 1 N/A 18406( 2) - 13-Aug-2026 16:14:37 - [ 29] Summary Form for Proposal 18406 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS-CENTER, WFC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=7 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT -180D TO -20D FROM 01, ORIENT -180D TO -20D FROM 07, ORIENT -180D TO -20D FROM 13, ORIENT -180D TO -20D FROM 19, ORIENT 190D TO 260 D, PAR 2 WITH 1, PAR 4 WITH 3, PATTERN 3 1-2, POS TARG -0.06, 0.095, POS TARG 0.099, 0.165, POS TARG 0.158, 0.070, POS TARG 29.94, -29.905, POS TARG 30, -30, POS TARG 30.099, -29.835, POS TARG 30.158, -29.93, SAME ORIENT AS 01, SAME ORIENT AS 04, SAME ORIENT AS 07, SAME ORIENT AS 10, SAME ORIENT AS 13, SAME ORIENT AS 16, SAME ORIENT AS 19, SAME ORIENT AS 22 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F390W, F435W, F555W, F606W, F625W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ANY, M31-BULGE-PHAT-BRICK-01-EAST, MACKERETH-WINDOW, NIDEVER-WINDOW, SANFORD-WINDOW ------------------------------------------------------------------------------------------------------------------------------------