8584( 8) - 08/21/01 15:34 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8584 Version: 8 Check-in Date: 21-Aug-2001 15:34:01 1.Proposal Title: Calibrating the Metallicity Dependence of the Cepheid PL Relation ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Robert Kennicutt University of Arizona CoI: Dr. Shoko Sakai University of California Los Angeles N CoI: Dr. Abhijit Saha NOAO N CoI: Dr. Laura Ferrarese University of California Los Angeles N ------------------------------------------------------------------------------------ 5. Abstract Uncertainty in the metal abundance dependence of the Cepheid PL relation remains as one of the largest sources of systematic error in the Cepheid distance scale and in the extragalactic distance scale as a whole. We propose to directly test and calibrate the metallicity dependence of the PL relation, by obtaining independent Pop II based distances to a sample of 6 Cepheid host galaxies with (Cepheid) metal abundances (0.2--2 Z_\odot), using the tip of the red giant branch (TRGB) method. The TRGB method offers the optimal combination of precision and metallicity insensitivity for this test. When combined with currently available Cepheid and TRGB distances, these data will provide: (1) A robust empirical calibration of the Cepheid metallicity dependence; (2) Hard limits on the systematic error in H_0 from metallicity effects; (3) Empirical constraints on theoretical models of Cepheids; (4) Tight limits on other systematic errors in Cepheid distances as functions of distance, stellar crowding, and extinction; (5) A valuable Pop II based cross- check on the zeropoint of the Pop I distance ladder. ------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 2] Observations Description ------------------------ Galaxy Sample. The table lists the 6 galaxies in the program, along with the technical details of the observations, including the assumed distances, expected TRGB magnitude, the required magnitude limits (1 mag below the tip in V and I), and the exposure times required to reach these limits. The galaxies were selected to cover the full range of metal abundances in the Cepheid fields, with particular emphasis on Z > 0.4 Z_\odot, which is poorly constrained by current observations. NGC 5457 (M101) has been observed with HST at two positions with 0.4Z_\odot and 2Z_\odot, and hence is a very high priority for the program. Galaxies with distances >>10 Mpc were not considered, because the observing time would be prohibitive. \medskip begintabularlcccccc & & & & Orbits & Orbits & Orbits Galaxy & (m - M) & I_tip + 1.0 & V_tip + 1.0 & F814W & F555W & Total NGC 300 & 26.66 & 23.7 & 24.7 & 0.5 & 0.5 & 1 NGC 3031 (M81) & 27.80 & 24.8 & 25.8 & 0.5 & 0.5 & 1 NGC 3351 & 30.01 & 27.0 & 28.0 & 8 & 6 & 14 NGC 3621 & 29.13 & 26.1 & 27.1 & 3 & 2 & 5 NGC 5457 (M101) & 29.34 & 26.3 & 27.3 & 3 & 2 & 5 IC 4182 & 28.36 & 25.4 & 26.4 & 1 & 1 & 2 endtabular Observational Requirements. Five of the galaxies in the program have distances >3 Mpc, and require imaging with HST to resolve the red giant stars. NGC 300 lies at a distance of 2.1 Mpc, and in principle is within reach of low precision TRGB measurements from the ground. However the differential test proposed here requires a very precise determination of the TRGB magnitude (Sigma < 0.1 mag), and this can only be obtained with HST. Each galaxy requires deep imaging with WFPC2 in F555W and F814W. The WFPC2 field will be centered in the halo or outer disk of each galaxy, to minimize stellar crowding and contamination. Exposure time requirements are based on the WFPC2 exposure time calculator, and verified against our own extensive experience with WFPC2 crowded field photometry in these passbands. Our previous experience demonstrates that measuring an accurate TRGB distance requires accurate stellar photometry to at least 1 magnitude below the TRGB, or M_I = -3. The F555W exposure times were calculated assuming a mean color V-I = 1.0 for the tip giants. \medskip Exposure Time Requirements. For NGC 300 and NGC 3031 (M81), both F555W and F814W cosmic ray split observations can be done in a single orbit. NGC 5457 (M101) and NGC 3621 are located at similar distances (7 Mpc), and we estimate that these galaxies will require five orbits each. For NGC 3621 the TRGB appears at I = 25.1, and we need to reach 1 mag deeper. According to the WFPC2 exposure time calculator, ~7000 seconds is needed to reach S/N=7, for stars at I=26.1 with the background surface brightness of 21 mag arcsec^-2. A total of ~4700 seconds is required for a F555W observations (V-I = 1.0 at I = 26.1). Thus, we estimate that five orbits in total are needed for the secure detection of the TRGB stars in NGC 3621. The same calculations apply to NGC 5457. IC 4182 is located at a distance of 4.7 Mpc, and similar calculations yield a required exposure time of 2 orbits (1 each in F555W and F814W). The most distant galaxy in this sample is NGC 3351 in the Leo I Group, at 10 Mpc. We need to observe RGB stars of I=27.0, V-I=1.0 with the I-band background surface brightness of 21 mag arcsec^-2. This translates into 8 orbits with F814W and 6 with F555W, a total of 14 orbits. This is a high priority object because it has the most metal-rich Cepheid field in the Key Project (~ 2.2 Z_\odot) \medskip Data Analysis. Analysis of the data will be carried out using the DAOPHOT and DoPHOT family of PSF- fitting photometry package. Our team has extensive experience with stellar photometry, the distance scale problem, and TRGB applications. Kennicutt is Co-PI of the HST Key Project on the Extragalactic Distance Scale, and led the part of the Key Project that dealt with the metallicity dependence of the PL relation (Kennicutt et al 1998). Saha is a Co-I both on the Key Project and the Sandage et al. distance scale team. He has extensive experience with HST and ground-based stellar photometry. Sakai is a Co-I on the Key Project and is an expert on the TRGB method, as applied from the ground and with HST. Ferrarese is a Co-I on the Key Project and has performed photometry on several of the galaxies. She also has extensive experience with artificial star simulations of crowded-field photometry on WFPC2 (Ferrarese et al 2000, in preparation). Real Time Justification ----------------------- One of our targets, NGC 3031 (M81), lies in the CVZ. We have requested 1 orbit total exposure time for the galaxy. The additional CVZ time would enable us to extend the depth of our stellar photometry and improve the precision of the TRGB magnitude measurement. However the core science requirements can be met in one orbit exposure time (without CVZ time), and hence the CVZ opportunity is not critical for our scientific objectives. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3031 GALAXY, Spiral RA=9H 55M 33.17S +/-0S, DEC=69D J2000 V=-34 V = 6.6+/-0.1 3' 55.1" +/-0" B-V = 0.8+/-0.1 Coordinate Source: OTHER_SOURCE 2 NGC3031-OFF GALAXY, Spiral RA=9H 54M 40.0S +/-0S, DEC=69D J2000 V=-34 V = 6.6+/-0.1 00' 00.0" +/-0" B-V = 0.8+/-0.1 Coordinate Source: OTHER_SOURCE 3 NGC300 GALAXY, Spiral RA=0H 54M 53.47S +/-0S, DEC=-37D J2000 V=+170 V = 7.9+/-0.1 41' 0.0" +/-0" B-V = 0.6+/-0.1 Coordinate Source: OTHER_SOURCE 4 NGC300-OFF GALAXY, Spiral RA-OFF=-9.93S +/- 0.1S, DEC-OFF= J2000 V=+170 V = 7.9+/-0.1 -417" +/- 1", FROM 3 B-V = 0.6+/-0.1 Coordinate Source: OTHER_SOURCE 5 NGC3351 GALAXY, Spiral RA=10H 43M 57.89S +/-0S, DEC=11D J2000 V=+778 V = 9.6+/-0.1 42' 14.4" +/-0" B-V = 0.7+/-0.1 Coordinate Source: OTHER_SOURCE 6 NGC3351-OFF GALAXY, Spiral RA-OFF=10.53S +/- 0.1S, DEC-OFF= J2000 V=+778 V = 9.6+/-0.1 -81" +/- 1", FROM 5 B-V = 0.7+/-0.1 Coordinate Source: OTHER_SOURCE 7 NGC3621 GALAXY, Spiral RA=11H 18M 16.06S +/-0S, DEC=- J2000 V=+727 V = 8.6+/-0.1 32D 48' 42.1" +/-0" B-V = 0.5+/-0.1 Coordinate Source: OTHER_SOURCE 8 NGC3621-OFF GALAXY, Spiral RA-OFF=4.1S +/- 0.1S, DEC- J2000 V=+727 V = 8.6+/-0.1 OFF=136" +/- 1", FROM 7 B-V = 0.5+/-0.1 Coordinate Source: OTHER_SOURCE 9 NGC5457 GALAXY, Spiral RA=14H 03M 12.48S +/-0S, DEC=54D J2000 V=+241 V = 7.7+/-0.1 20' 55.3" +/-0" B-V = 0.4+/-0.1 Coordinate Source: OTHER_SOURCE 10 NGC5457-OFF GALAXY, Spiral RA-OFF=11.5S +/- 0.1S, DEC-OFF=- J2000 V=+241 V = 7.7+/-0.1 549" +/- 1", FROM 9 B-V = 0.4+/-0.1 Coordinate Source: OTHER_SOURCE 11 IC4182 GALAXY, Spiral RA=13H 05M 49.53S +/-0S, DEC=37D J2000 V=+321 B = 13.0+/-0.7 36' 17.6" +/-0" Coordinate Source: OTHER_SOURCE 12 IC4182-OFF GALAXY, Spiral RA-OFF=-5.6S +/- 0.1S, DEC-OFF=- J2000 V=+321 B = 13.0+/-0.7 124" +/- 1", FROM 11 Coordinate Source: OTHER_SOURCE 8584( 8) - 08/21/01 15:34 - [ 4] Visit: 01 Visit Priority: Visit Requirements: CVZ ORIENT 180D TO 360D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC3031-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2200 S ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC3031-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2200 S ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 5] Visit: 02 Visit Priority: Visit Requirements: ORIENT 330D TO 80D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 NGC300-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 22 NGC300-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 6] Visit: 03 Visit Priority: Visit Requirements: ORIENT 278D TO 298D; GROUP 3-6 WITHIN 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC3351-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2400 S ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC3351-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S POS TARG 0.0, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 33 NGC3351-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 34 NGC3351-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S POS TARG 0.6, 0. ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 7] Visit: 04 Visit Priority: Visit Requirements: SAME ORIENT AS 3; GROUP 3-6 WITHIN 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 41 NGC3351-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG -0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 42 NGC3351-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S POS TARG -0.6, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 8] Visit: 05 Visit Priority: Visit Requirements: SAME ORIENT AS 3; GROUP 3-6 WITHIN 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 51 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2400 S ------------------------------------------------------------------------------------------------------------------------------------ 52 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.6, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 53 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG -0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 54 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG -0.6, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 9] Visit: 06 Visit Priority: Visit Requirements: SAME ORIENT AS 3; GROUP 3-6 WITHIN 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 61 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2400 S POS TARG 0.0,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 62 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 63 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.0, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 64 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 10] Visit: 07 Visit Priority: Visit Requirements: ORIENT 288D TO 10D GROUP 7-8 WITHIN 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 71 NGC5457-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S ------------------------------------------------------------------------------------------------------------------------------------ 72 NGC5457-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2800 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 11] Visit: 08 Visit Priority: Visit Requirements: SAME ORIENT AS 7 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 81 NGC5457-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S ------------------------------------------------------------------------------------------------------------------------------------ 82 NGC5457-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2800 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 83 NGC5457-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2800 S POS TARG -0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 12] Visit: 09 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 91 IC4182-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S ------------------------------------------------------------------------------------------------------------------------------------ 92 IC4182-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 13] Visit: 10 Visit Priority: Visit Requirements: ORIENT 305D TO 325D; GROUP 10-11 WITHIN 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 101 NGC3621-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S ------------------------------------------------------------------------------------------------------------------------------------ 102 NGC3621-OFF WFPC2 IMAGE WFALL F555W 5398 CR-SPLIT=DEF 1 2600 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 14] Visit: 11 Visit Priority: Visit Requirements: SAME ORIENT AS 10; GROUP 10-11 WITHIN 90D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 111 NGC3621-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S ------------------------------------------------------------------------------------------------------------------------------------ 112 NGC3621-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 113 NGC3621-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG -0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 15] Visit: 56 Visit Priority: Visit Requirements: ORIENT 294.900299D TO 294.900299D; BEFORE 21-JAN-2001 On Hold Comments: Additional Comments: This is a HOPR repeat of Visit 06. The BEFORE 21-JAN-2001 requirement enforces the original GROUP 03-06 WITHIN 90D since Visit 04 executed on 22- OCT-2000 and was the first to execute. The U3 ORIENT is an exact match converted from the PA_V3 value of 114.900299D from the Visit 06 data headers. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 61 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2400 S POS TARG 0.0,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 62 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 63 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.0, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 64 NGC3351-OFF WFPC2 IMAGE WFALL F814W 7921 CR-SPLIT=DEF 1 2600 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8584( 8) - 08/21/01 15:34 - [ 16] Summary Form for Proposal 8584 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFALL ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ORIENT 180D TO 360D ORIENT 330D TO 80D ORIENT 278D TO 298D; GROUP 3-6 WITHIN 90D POS TARG 0.0, 0.6 POS TARG 0.6, 0.6 POS TARG 0.6, 0. SAME ORIENT AS 3; GROUP 3-6 WITHIN 90D POS TARG -0.6,-0.6 POS TARG -0.6, 0.0 POS TARG 0.6, 0.0 POS TARG 0.0,-0.6 POS TARG 0.6,-0.6 ORIENT 288D TO 10D GROUP 7-8 WITHIN 90D SAME ORIENT AS 7 ORIENT 305D TO 325D; GROUP 10-11 WITHIN 90D SAME ORIENT AS 10; GROUP 10-11 WITHIN 90D ORIENT 294.900299D TO 294.900299D; BEFORE 21-JAN-2001 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3031-OFF NGC300-OFF NGC3351-OFF NGC5457-OFF IC4182-OFF NGC3621-OFF ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 5398 7921 ------------------------------------------------------------------------------------------------------------------------------------