10471( 6) - 04/27/05 08:47 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 10471 Version: 6 Check-in Date: 27-Apr-2005 12:47:06 1.Proposal Title: The Bottom of the Main Sequence in the Old Metal-Rich Cluster NGC 6791 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle 4. Parallel Pointing Tolerance GO 14 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. Ivan R. King University of Washington CoI: Dr. Jay Anderson Rice University N CoI: Prof. Giampaolo Piotto Universita di Padova N CoI: Dr. Luigi R. Bedin European Southern Observatory - Germany N CoI: Dr. Santi Cassisi INAF, Osservatorio Astronomico di Teramo N CoI: Dr. Maurizio Salaris Liverpool John Moores University N ------------------------------------------------------------------------------------ 6. Abstract This is the second epoch of GO-9815, whose first-epoch abstract was: We propose a photometric study of the lowest part of the main sequence of NGC 6791, an old, rich open cluster whose metallicity is considerably higher than solar. The cluster is rich enough that a single ACS/WFC field will have ample stars for the study. For the faintest stars, proper-motion separation of cluster from field is essential; hence we include Cycle 14 observations. These should give us a color-magnitude diagram and luminosity function that reach into the region of the hydrogen-burning limit, thus extending the study of the latter into a new domain of metallicity. Observational data of this type will allow theoreticians to check many aspects of their theories of stellar structure. We also expect to see the white dwarf sequence of the cluster. Our team has experience with studies of this type, and has provided the geometric- distortion calibration of ACS. ------------------------------------------------------------------------------------ 10471( 6) - 04/27/05 08:47 - [ 2] Observations Description ------------------------ These are second-epoch observations for proper motions, and must be taken at the same position and orientation as those of the first epoch. Since the purpose is astrometric, only F814W is used, it being chosen because it is the filter that will most enhance our existing photometry. Each orbit begins with a short exposure, and the remainder of the orbit is filled out with two long exposures. The exposures are dithered for optimum astrometry (same dithers as in first epoch). Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 10471( 6) - 04/27/05 08:47 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6791 STELLAR CLUSTER, OPEN RA=19H21M0.0000S +/- 0.1", J2000 V = 9.5+/-0.1 CLUSTER DEC=+37D47'0.00" +/- 0.1" Coordinate Source: HST_IMAGE 10471( 6) - 04/27/05 08:47 - [ 4] Visit: 01 Visit Priority: Visit Requirements: PCS MODE FINE; NUMBER OF GYROS 3; ORIENT 174.565D TO 174.565 D; BEFORE 05- AUG-2005:00:00:00 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 30 S GS ACQ SCENARIO BASE13GO ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 1200 S ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 1200 S POS TARG 0.1412, 0.0363 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 30 S POS TARG 0.0665, 0.1886 ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 1264 S POS TARG 0.0748, 0.1476 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 1264 S POS TARG -0.0166, 0.107 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 30 S POS TARG 0.1827, 0.0813 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 1264 S POS TARG 0.0665,-0.0114 ------------------------------------------------------------------------------------------------------------------------------------ 9 NGC6791 ACS/WFC ACCUM WFC-FIX F814W CR-SPLIT=NO,GAIN=2 1 1264 S POS TARG 0.0581, 0.0713 Comments: The TTRB has given permission for 3-gyro mode. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC6791 1 ACS/WFC ACCUM WFC-FIX F814W none none none none 1 N/A NGC6791 2 ACS/WFC ACCUM WFC-FIX F814W none none none none 1 N/A NGC6791 3 ACS/WFC ACCUM WFC-FIX F814W none none none none 1 N/A NGC6791 4 ACS/WFC ACCUM WFC-FIX F814W none none none none 2 N/A NGC6791 5 ACS/WFC ACCUM WFC-FIX F814W none none none none 2 N/A NGC6791 6 ACS/WFC ACCUM WFC-FIX F814W none none none none 2 N/A NGC6791 7 ACS/WFC ACCUM WFC-FIX F814W none none none none 3 N/A NGC6791 8 ACS/WFC ACCUM WFC-FIX F814W none none none none 3 N/A NGC6791 9 ACS/WFC ACCUM WFC-FIX F814W none none none none 3 N/A 10471( 6) - 04/27/05 08:47 - [ 5] Summary Form for Proposal 10471 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WFC-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO GAIN=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE FINE; NUMBER OF GYROS 3; ORIENT 174.565D TO 174.565 D; BEFORE 05-AUG-2005 00 00 00 GS ACQ SCENARIO BASE13GO POS TARG 0.1412, 0.0363 POS TARG 0.0665, 0.1886 POS TARG 0.0748, 0.1476 POS TARG -0.0166, 0.107 POS TARG 0.1827, 0.0813 POS TARG 0.0665,-0.0114 POS TARG 0.0581, 0.0713 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC6791 ------------------------------------------------------------------------------------------------------------------------------------