18058( 3) - 14-Aug-2025 16:35:20 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18058 Version: 3 Check-in Time: 14-Aug-2025 16:35:20 STScI Edit Number: 0 Title The chemical composition of pristine gas through first-population stars in NGC 121 ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Maria Vittoria Legnardi Universita degli Studi di Padova Y CoI: Prof. Antonino Paolo Milone Universita degli Studi di Padova N CoI: Dr. Giacomo Cordoni Australian National University N CoI: Prof. E. P. Lagioia Yunnan University N CoI: Dr. Emanuele Dondoglio INAF - Istituto Nazionale di Astrofisica N CoI: Fabrizio Muratore Universita degli Studi di Padova N CoI: Dr. Emanuele Bortolan Universita degli Studi di Padova N CoI: Tuila Ziliotto Universita degli Studi di Padova N CoI: Dr. Marco Tailo Universita di Bologna N CoI: Dr. Alessandra Mastrobuono Universita degli Studi di Padova N Battisti CoI: Dr. Anna Fabiola Marino INAF - Osservatorio Astronomico di Padova N ------------------------------------------------------------------------------------ Abstract We propose to uncover, for the first time, the original chemical composition of the gas that formed an ancient globular cluster (GC) in the Small Magellanic Cloud (SMC). Our target is NGC 121, the only SMC cluster old enough to trace the properties of primordial star-forming gas. By combining archival and new HST/UVIS WFC3 F275W images, we will analyze stars in this cluster to reconstruct the conditions present in the early Universe. Our focus is on first-population (1P) stars, which preserve the chemical signature of the proto-cluster cloud. In Milky Way GCs, the 1P sequence often shows unexpected features, such as internal metallicity variations up to ~0.3 dex. These findings challenge the long-standing view that 1P stars are chemically homogeneous, suggesting instead that the star-forming gas was either inhomogeneous or later altered by stellar feedback. However, such studies remain limited to Galactic environments. NGC 121 provides a unique opportunity to investigate whether these internal chemical spreads are a universal property of globular clusters or depend on the host galaxy environment. By studying this SMC cluster, we will gain insight into early chemical enrichment processes in low-mass galaxies and explore the broader connection between star cluster formation and galactic evolution. ------------------------------------------------------------------------------------ Observations Description ------------------------ This proposal aims to determine the chemical composition of the primordial gas from which the ancient globular cluster NGC 121, in the Small Magellanic Cloud, formed. To achieve this goal, we will obtain new observations of NGC121 with the WFC3/UVIS camera using the F275W filter. These data will complement existing exposures in the F336W, F438W, and F814W filters obtained under programs GO-13435 and GO-10396, which target overlapping fields centered on NGC 18058( 3) - 14-Aug-2025 16:35:20 - [ 2] 121. By combining the new F275W observations with the archival datasets, we will construct the multi-band photometry necessary to accurately probe the chemical composition of the early gas clouds from which globular cluster stars formed in the early Universe. To allow flexibility in the scheduling of HST orbits, our observation plan consists of 15 separate visits, each using 1 orbit. Each visit will include two F275W exposures of 1297 s, enabling us to achieve a signal-to-noise ratio of ~100 at the base of the red giant branch, sufficient to robustly characterize the chemical properties of the cluster's stellar populations. All exposures will be dithered to optimize PSF sampling, cosmic ray rejection, and astrometric precision. To mitigate CTE degradation, exposures will be flashed according to current STScI recommendations. ------------------------------------------------------------------------------------ 18058( 3) - 14-Aug-2025 16:35:20 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC-121 EXT-CLUSTER, GLOBULAR RA=00H26M49.0000S, J2000 V = 11.24 CLUSTER DEC=-71D32'10.00" Reference Frame: Other: SIMBAD Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 18058( 3) - 14-Aug-2025 16:35:20 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 10 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 270 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 18058( 3) - 14-Aug-2025 16:35:20 - [ 5] Visit: 01 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG -4, +4; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 6] Visit: 02 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG 0, +4; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 7] Visit: 03 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG +4, +4; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 8] Visit: 04 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG -4, 0; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 9] Visit: 05 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG 0, 0; PATTERN 1 S (2594 S) 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 10] Visit: 06 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG +4, 0; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 11] Visit: 07 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG -4, -4; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 12] Visit: 08 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG 0, -4; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 13] Visit: 09 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG +4, -4; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 14] Visit: 10 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG 0, +2; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 15] Visit: 11 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG -2, +1; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 16] Visit: 12 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG +2, +1; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 17] Visit: 13 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG -2, -2; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 18] Visit: 14 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG +2, -2; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 19] Visit: 15 (NGC121) Visit Requirements: On Hold Comments: Additional Comments: 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 NGC-121 WFC3/UVI ACCUM UVIS2 F275W FLASH=20 1 1297 S POS TARG +2, +2; PATTERN S (2594 S) 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 1 none none none 1 N/A S NGC-121 1 WFC3/UVI ACCUM UVIS2 F275W 2 none none none 1 N/A S 18058( 3) - 14-Aug-2025 16:35:20 - [ 20] Summary Form for Proposal 18058 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=20 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 1, POS TARG +2, +1, POS TARG +2, +2, POS TARG +2, -2, POS TARG +4, +4, POS TARG +4, -4, POS TARG +4, 0, POS TARG -2, +1, POS TARG -2, -2, POS TARG -4, +4, POS TARG -4, -4, POS TARG -4, 0, POS TARG 0, +2, POS TARG 0, +4, POS TARG 0, -4, POS TARG 0, 0 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F275W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC-121 ------------------------------------------------------------------------------------------------------------------------------------