18405( 2) - 17-Aug-2026 15:23:17 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18405 Version: 2 Check-in Time: 17-Aug-2026 15:23:17 STScI Edit Number: 0 Title The First Direct Measurement of UV Extinction Curves Outside the Local Group in the LMC-like galaxy, NGC 55 ------------------------------------------------------------------------------------ Type Cycle GO 34 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Geoffrey C. Clayton Space Science Institute Y CoI: Dr. Karl D. Gordon Space Telescope Science Institute N CoI: Dr. Marjorie Decleir Space Telescope Science Institute - ESA N CoI: Dr. Ralph C. Bohlin Space Telescope Science Institute N CoI: Dr. Petia Yanchulova Bulgarian Academy of Sciences N ------------------------------------------------------------------------------------ Abstract The observations proposed here will be the first UV spectra of reddened OB stars in the Sculptor galaxy, NGC 55, using HST/STIS. These new observations will be used to make the first direct measurements of UV extinction properties in a galaxy outside the Local Group. The UV extinction properties of interstellar dust have now been surveyed for five galaxies in the Local Group (MW, LMC, SMC, M31, M33). There is a family of UV extinction curves that describes the Local Group. Is this family of extinction curves present in other more distant galaxies or is it unique to the Local Group? It is necessary to study a galaxy, outside the Local Group yet close enough for individual stars to be observed. NGC 55 bears a very close resemblance to the LMC in both morphology and metallicity. This makes it likely that the new observations will show significant variations in the dust extinction properties across NGC 55. Extinction curves will be constructed using the standard pair method where observations of the reddened star are compared to a stellar atmosphere model of the same spectral type. In order to analyze the composition and size distributions of the dust grain population, s Maximum Entropy Modeling will be used. The results will be used to provide more accurate dust parameters for radiative transfer modeling of galaxies which cannot be done without a detailed knowledge of the characteristics of this absorbing medium. We are proposing to observe five stars in NGC 55 using HST/STIS and the G140L, G230L, and G430L gratings that will sample the dust in the 30-Dor-like regions in NGC 55 as well as in other parts of the galaxy. ------------------------------------------------------------------------------------ Observations Description ------------------------ The small aperture and high sensitivity of HST/STIS are ideal for obtaining UV spectra of stars in the crowded fields of NGC 55. The ability to use the 0.2 x 0.2 slit will allow us to avoid including close neighbors. HST imaging has been examined for each of the targets to confirm that they are single stars (Dalcanton et al., 2009). The entire wavelength range covered by the G140L (1150-1730 A) and G230L (1570-3180 A) gratings is needed to obtain the UV extinction curve, including the near-UV, the 2175A bump, and 18405( 2) - 17-Aug-2026 15:23:17 - [ 2] the far-UV rise. In addition, the stars will be observed with the G430L grating. The wavelengths sampled with the G430L grating spectroscopy will furnish critical temperature and surface gravity diagnostics that are essential to disentangle the slope of the UV extinction from stellar effects. In particular, measuring the size of the Balmer Jump (3645 A) aids in choosing the closest atmosphere model for comparison. Using the STIS ETC and assuming a B0I star with V=20.0, and reddening of E(B-V) = 0.3, the exposures in both UV gratings can be obtained in three orbits each with an average S/N >10 if one bins 7 pixels. A similar S/N of >10 can be obtained for the G430L grating in one orbit. These calculations assume Cardelli et al. (1989) R(V)= 3.1 extinction. If the extinction is more LMC/SMC-like, one can bin more pixels to get the required S/N. Good S/N UV spectra using HST/STIS have been obtained in one orbit using the G140L and G230L gratings for stars in M31 and M33 with similar reddenings and spectral types as the proposed targets in NGC 55 (Clayton et al., 2025; Gordon et al., 2026). The NGC 55 stars are about one magnitude fainter on average, so three orbits per target are required for the UV gratings. The targets are all between early-B and mid-O type and have V magnitudes =19th, well below the bright limits for the MAMAs. NGC 55 has orbit visibilities of about 51 minutes. The first orbit for each target has an overhead of 17.5 minutes including GS Acq, STIS/ACQ, and grating overhead. The second to fourth orbits have overheads of 11.5-14.5 minutes including the GS Reacq and the grating overhead. The G430L grating will be done during the first orbit for each target. So, the G430L grating will have an exposure of 2010s, and the G140L and G230L will have total exposures from the three orbits of 6930s. Since the observations are using the 0.2 x 0.2 slit no peakup is required. The plan is to observe a total of 5 stars in NGC 55 for 7 orbits per star. Therefore, 35 orbits are requested. ------------------------------------------------------------------------------------ 18405( 2) - 17-Aug-2026 15:23:17 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 D-28 EXT-STAR, B0-B2 III-I RA=00H14M28.5478S, J2000 V = 20.11 +/- 0.01 V-I=0.03 DEC=-39D10'52.81" Reference Frame: ICRS Extended: NO 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 ------------------------------------------------------------------------------------------------------------------------------------ 2 C1-13 EXT-STAR, B0-B2 III-I RA=00H14M51.7970S, J2000 V = 20.09 +/- 0.01 V-I=0.045 DEC=-39D10'56.88" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 3 C2-20 EXT-STAR, B0-B2 III-I RA=00H14M53.5294S, J2000 V = 19.36 +/- 0.01 V-I=0.56 DEC=-39D12'5.79" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 4 D-31 EXT-STAR, B0-B2 III-I RA=00H14M31.9682S, J2000 V = 20.21 +/- 0.01 V-I=0.14 DEC=-39D10'34.50" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 5 B-33 EXT-STAR, SUPERGIANT O RA=00H15M33.4820S, J2000 V = 19.78 +/- 0.01 V-I=0.10 DEC=-39D15'10.29" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 18405( 2) - 17-Aug-2026 15:23:17 - [ 4] Visit: 01 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 D-28 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D-28 STIS/CCD ACCUM 0.2X0.2 G430L 4300 1 1800 S see below (2072 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 | ------------------------------------------------------------------------------------------------------------------------------------ D-28 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A D-28 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 1 1 1036.0 S D-28 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 2 1 1036.0 S 18405( 2) - 17-Aug-2026 15:23:17 - [ 5] Visit: 02 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 D-28 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D-28 STIS/NUV ACCUM 0.2X0.2 G230L 2376 3 2000 S -MAMA see below (7124 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 | ------------------------------------------------------------------------------------------------------------------------------------ D-28 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A D-28 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 1 none 1 2012.0 S -MAMA D-28 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 2 none 2 2584.0 S -MAMA D-28 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 3 none 3 2528.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 6] Visit: 03 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 D-28 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D-28 STIS/FUV ACCUM 0.2X0.2 G140L 1425 3 2000 S -MAMA see below (7245 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 | ------------------------------------------------------------------------------------------------------------------------------------ D-28 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A D-28 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 1 none 1 2091.0 S -MAMA D-28 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 2 none 2 2584.0 S -MAMA D-28 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 3 none 3 2570.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 7] Visit: 04 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 C1-13 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 C1-13 STIS/CCD ACCUM 0.2X0.2 G430L 4300 1 1800 S see below (2072 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 | ------------------------------------------------------------------------------------------------------------------------------------ C1-13 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A C1-13 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 1 1 1036.0 S C1-13 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 2 1 1036.0 S 18405( 2) - 17-Aug-2026 15:23:17 - [ 8] Visit: 05 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 C1-13 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 C1-13 STIS/NUV ACCUM 0.2X0.2 G230L 2376 3 2000 S -MAMA see below (7124 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 | ------------------------------------------------------------------------------------------------------------------------------------ C1-13 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A C1-13 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 1 none 1 2012.0 S -MAMA C1-13 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 2 none 2 2584.0 S -MAMA C1-13 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 3 none 3 2528.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 9] Visit: 06 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 C1-13 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 C1-13 STIS/FUV ACCUM 0.2X0.2 G140L 1425 3 2000 S -MAMA see below (7245 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 | ------------------------------------------------------------------------------------------------------------------------------------ C1-13 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A C1-13 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 1 none 1 2091.0 S -MAMA C1-13 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 2 none 2 2584.0 S -MAMA C1-13 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 3 none 3 2570.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 10] Visit: 07 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 C2-20 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 C2-20 STIS/CCD ACCUM 0.2X0.2 G430L 4300 1 1800 S see below (2072 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 | ------------------------------------------------------------------------------------------------------------------------------------ C2-20 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A C2-20 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 1 1 1036.0 S C2-20 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 2 1 1036.0 S 18405( 2) - 17-Aug-2026 15:23:17 - [ 11] Visit: 08 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 C2-20 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 C2-20 STIS/NUV ACCUM 0.2X0.2 G230L 2376 3 2000 S -MAMA see below (7124 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 | ------------------------------------------------------------------------------------------------------------------------------------ C2-20 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A C2-20 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 1 none 1 2012.0 S -MAMA C2-20 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 2 none 2 2584.0 S -MAMA C2-20 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 3 none 3 2528.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 12] Visit: 09 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 C2-20 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 C2-20 STIS/FUV ACCUM 0.2X0.2 G140L 1425 3 2000 S -MAMA see below (7245 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 | ------------------------------------------------------------------------------------------------------------------------------------ C2-20 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A C2-20 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 1 none 1 2091.0 S -MAMA C2-20 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 2 none 2 2584.0 S -MAMA C2-20 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 3 none 3 2570.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 13] Visit: 10 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 D-31 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D-31 STIS/CCD ACCUM 0.2X0.2 G430L 4300 1 1800 S see below (2072 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 | ------------------------------------------------------------------------------------------------------------------------------------ D-31 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A D-31 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 1 1 1036.0 S D-31 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 2 1 1036.0 S 18405( 2) - 17-Aug-2026 15:23:17 - [ 14] Visit: 11 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 D-31 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D-31 STIS/NUV ACCUM 0.2X0.2 G230L 2376 3 2000 S -MAMA see below (7124 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 | ------------------------------------------------------------------------------------------------------------------------------------ D-31 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A D-31 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 1 none 1 2012.0 S -MAMA D-31 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 2 none 2 2584.0 S -MAMA D-31 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 3 none 3 2528.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 15] Visit: 12 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 D-31 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 D-31 STIS/FUV ACCUM 0.2X0.2 G140L 1425 3 2000 S -MAMA see below (7245 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 | ------------------------------------------------------------------------------------------------------------------------------------ D-31 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A D-31 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 1 none 1 2091.0 S -MAMA D-31 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 2 none 2 2584.0 S -MAMA D-31 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 3 none 3 2570.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 16] Visit: 13 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 B-33 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 B-33 STIS/CCD ACCUM 0.2X0.2 G430L 4300 1 1800 S see below (2072 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 | ------------------------------------------------------------------------------------------------------------------------------------ B-33 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A B-33 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 1 1 1036.0 S B-33 2 STIS/CCD ACCUM 0.2X0.2 G430L 4300 none none none 2 1 1036.0 S 18405( 2) - 17-Aug-2026 15:23:17 - [ 17] Visit: 14 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 B-33 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 B-33 STIS/NUV ACCUM 0.2X0.2 G230L 2376 3 2000 S -MAMA see below (7124 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 | ------------------------------------------------------------------------------------------------------------------------------------ B-33 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A B-33 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 1 none 1 2012.0 S -MAMA B-33 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 2 none 2 2584.0 S -MAMA B-33 2 STIS/NUV ACCUM 0.2X0.2 G230L 2376 none none 3 none 3 2528.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 18] Visit: 15 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 B-33 STIS/CCD ACQ F28X50LP MIRROR 1 10 S (10 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 B-33 STIS/FUV ACCUM 0.2X0.2 G140L 1425 3 2000 S -MAMA see below (7245 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 | ------------------------------------------------------------------------------------------------------------------------------------ B-33 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A B-33 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 1 none 1 2091.0 S -MAMA B-33 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 2 none 2 2584.0 S -MAMA B-33 2 STIS/FUV ACCUM 0.2X0.2 G140L 1425 none none 3 none 3 2570.0 S -MAMA 18405( 2) - 17-Aug-2026 15:23:17 - [ 19] Summary Form for Proposal 18405 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, G430L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names B-33, C1-13, C2-20, D-28, D-31 ------------------------------------------------------------------------------------------------------------------------------------