!  File:  5481P.PROP
!  Database:  PEPDB
!  Date:  14-FEB-1994:15:23:23

coverpage:

  title_1:         AGES FOR THE OUTERMOST GLOBULAR CLUSTERS: THE FORMATION
    title_2:       OF THE GALACTIC HALO: CYCLE 4 HIGH
    sci_cat:       COOL STARS
    sci_subcat:    OLD CLUSTERS
    proposal_for:  GO
    pi_fname:      JAMES
    pi_mi:         E.
    pi_lname:      HESSER
    pi_inst:       4628
    pi_country:    CANADA
    pi_phone:      604-363-0007
    num_pri:       8
    wf_pc:         Y
    off_fname:     JAMES E.
    off_lname:     HESSER
    off_title:     DIRECTOR
    off_inst:      4628
    off_addr_1:    DOMINION ASTROPHYSICAL OBSERVATORY
    off_addr_2:    5071 W. SAANICH RD.
    off_city:      VICTORIA
    off_state:     BC
    off_zip:       V8X 4M6
    off_country:   CANADA
    off_phone:     604-363-0007
! end of coverpage

abstract:

    line_1:        We propose observations of globular clusters in the outermost regions
    line_2:        of the Galactic halo that will answer fundamental questions about the
    line_3:        early epoch of the formation of the Galaxy.  We have selected two
    line_4:        clusters (NGC 2419 and Pal 4) which lie at Galactocentric
    line_5:        distances near 100 kpc.  Using deep HST WFPC2 images in the V and I
    line_6:        bands, we will reach the main-sequence turnoffs in these clusters with
    line_7:        photometric accuracy sufficient to obtain ages (relative to nearby
    line_8:        clusters and to clusters in the Galactic bulge) with a precision of
    line_9:        better than 1 Gyr.  This age comparison will be an essential component
    line_10:       in reconstructing the sequence of events during early Galactic
    line_11:       formation history, and our project is complementary to HST programs
    line_12:       for measuring ages of globular clusters in the Galactic bulge.

!
! end of abstract

general_form_proposers:

  lname:           HESSER
    fname:         JAMES E.
    inst:          4628
    country:       CANADA

!

  lname:           BELL
    fname:         ROGER A.
    inst:          2620
    country:       USA

!

  lname:           BOLTE
    fname:         MICHAEL
    inst:          1552
    country:       USA

!

  lname:           BOND
    fname:         HOWARD E.
    inst:          3470
    country:       USA

!

  lname:           FAHLMAN
    fname:         GREGORY G.
    inst:          4618
    country:       CANADA

!

  lname:           HARRIS
    fname:         WILLIAM E.
    inst:          4642
    country:       CANADA

!

  lname:           MCCLURE
    fname:         ROBERT D.
    inst:          4628
    country:       CANADA

!

  lname:           RICHER
    fname:         HARVEY B.
    inst:          4618
    country:       CANADA

!

  lname:           STETSON
    fname:         PETER B.
    inst:          4628
    country:       CANADA

!

  lname:           VANDENBERG
    fname:         DON A.
    inst:          4670
    country:       CANADA

!

  lname:           VAN DEN BERGH
    fname:         SIDNEY
    inst:          4628
    country:       CANADA

!
! end of general_form_proposers block

general_form_text:

  question:        3
    section:       1
    line_1:        We will use the PC chip of the WFPC2 to observe two of the most
    line_2:        distant known Galactic globular clusters, Pal 4 and NGC 2419, for the
    line_3:        purpose of determining and comparing their ages.
    line_5:        In both clusters we will observe two separate fields, in order to
    line_6:        measure enough stars for the age determinations. In each of the four
    line_7:        fields we will obtain eight 1400-sec exposures in F555W ("V") and
    line_8:        eight 1300-sec exposures in F814W ("I").  Since there are 8 separate
    line_9:        exposures in each filter, we will not do any further CR-SPLITs.  We
    line_10:       will move the telescope about 1/2 pixel between individual exposures,
    line_11:       in order to better sample the PSF. The aim of the program is to
    line_12:       achieve a precision of 0.06 mag in the V-I color at V = 25, in order
    line_13:       to define the stellar sequences in the vicinity of the main-sequence
    line_14:       turnoffs for accurate age determinations through comparison with
    line_15:       theoretical evolutionary tracks.
    line_17:       A second set of short exposures (six 60-sec in V and six 30-sec in I)
    line_18:       will be obtained in each field, in order to measure the brighter
    line_19:       stars on the red-giant branch and a sample of horizontal-branch stars
    line_20:       and assure a proper tie-in to ground-based photometry of the same
    line_21:       objects.  Since our deep fields have been carefully selected to be
    line_22:       free of bright stars, the pointings for the short exposures will be
    line_23:       shifted about half a field diameter toward the cluster center in order

!

  question:        3
    section:       2
    line_1:        to include several brighter stars.  The telescope will again be moved
    line_2:        about 1/2 pixel between individual exposures.
    line_4:        The spacecraft roll angle is arbitrary, but all exposures on a given
    line_5:        field should be taken at the SAME roll angle.

!

  question:        4
    section:       1
    line_1:        (See Phase I proposal.)

!

  question:        5
    section:       1
    line_1:        None.

!

  question:        6
    section:       1
    line_1:        None.

!

  question:        7
    section:       1
    line_1:        (See Phase I proposal.)

!

  question:        8
    section:       1
    line_1:        None.

!

  question:        9
    section:       1
    line_1:        (See Phase I proposal.)

!

  question:        10
    section:       1
    line_1:        (See Phase I proposal.)

!
!end of general form text

general_form_address:

  lname:           HESSER
    fname:         JAMES E.
    category:      PI
    inst:          4628
    addr_1:        DOMINION ASTROPHYSICAL OBSERVATORY
    addr_2:        5071 W. Saanich Rd.
    city:          VICTORIA
    state:         BC
    zip:           V8X 4M6
    country:       CANADA
    phone:         604-363-0007
    telex:         hesser@dao.nrc.ca

!
! end of general_form_address records

fixed_targets:

    targnum:       1
    name_1:        PAL4-NORTH
    descr_1:       C,201
    pos_1:         RA = 11H 29M 18.88S +/- 1",
    pos_2:         DEC = +28D 59' 03.2" +/- 1",
    pos_3:         PLATE-ID=019K
    equinox:       J2000
    comment_1:     NORTHERN FIELD IN DISTANT GLOBULAR
    comment_2:     CLUSTER PAL 4
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       2
    name_1:        PAL4-NORTH-OFF
    descr_1:       C,201
    pos_1:         RA-OFF = 0S +/- 0.08S,
    pos_2:         DEC-OFF = -20" +/- 1",
    pos_3:         FROM 1
    equinox:       J2000
    comment_1:     FIELD IN DISTANT GLOBULAR CLUSTER
    comment_2:     PAL 4, OFFSET 20" SOUTH OF DEEP
    comment_3:     FIELD TO INCLUDE BRIGHTER STARS.
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       3
    name_1:        PAL4-SOUTH
    descr_1:       C,201
    pos_1:         RA = 11H 29M 16.47S +/- 1",
    pos_2:         DEC = +28D 57' 26.4" +/- 1",
    pos_3:         PLATE-ID=019K
    equinox:       J2000
    comment_1:     SOUTHERN FIELD IN DISTANT GLOBULAR
    comment_2:     CLUSTER PAL 4
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       4
    name_1:        PAL4-SOUTH-OFF
    descr_1:       C,201
    pos_1:         RA-OFF = 0S +/- 0.08S,
    pos_2:         DEC-OFF = +20" +/- 1",
    pos_3:         FROM 3
    equinox:       J2000
    comment_1:     FIELD IN DISTANT GLOBULAR CLUSTER
    comment_2:     PAL 4, OFFSET 20" NORTH OF DEEP
    comment_3:     FIELD TO INCLUDE BRIGHTER STARS.
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       5
    name_1:        NGC2419-NORTH
    descr_1:       C,201
    pos_1:         RA = 07H 38M 09.04S +/- 1",
    pos_2:         DEC = +38D 54' 27.9" +/- 1",
    pos_3:         PLATE-ID=01H9
    equinox:       J2000
    comment_1:     NORTHERN FIELD IN DISTANT GLOBULAR
    comment_2:     CLUSTER NGC 2419.
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       6
    name_1:        NGC2419-NORTH-OFF
    descr_1:       C,201
    pos_1:         RA-OFF = 0S +/- 0.08S,
    pos_2:         DEC-OFF = -20" +/- 1",
    pos_3:         FROM 5
    equinox:       J2000
    comment_1:     FIELD IN DISTANT GLOBULAR CLUSTER
    comment_2:     NGC 2419, OFFSET 20" SOUTH OF DEEP
    comment_3:     FIELD TO INCLUDE BRIGHTER STARS.
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       7
    name_1:        NGC2419-SOUTH
    descr_1:       C,201
    pos_1:         RA = 07H 38M 09.21S +/- 1",
    pos_2:         DEC = +38D 51' 35.4" +/- 1",
    pos_3:         PLATE-ID=01H9
    equinox:       J2000
    comment_1:     SOUTHERN FIELD IN DISTANT GLOBULAR
    comment_2:     CLUSTER NGC 2419
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       8
    name_1:        NGC2419-SOUTH-OFF
    descr_1:       C,201
    pos_1:         RA-OFF = 0S +/- 0.08S,
    pos_2:         DEC-OFF = +20" +/- 1",
    pos_3:         FROM 7
    equinox:       J2000
    comment_1:     FIELD IN DISTANT GLOBULAR CLUSTER
    comment_2:     NGC 2419, OFFSET 20" NORTH OF DEEP
    comment_3:     FIELD TO INCLUDE BRIGHTER STARS.
    fluxnum_1:     1
    fluxval_1:     V=25

!
! end of fixed targets

! No solar system records found

! No generic target records found

exposure_logsheet:

    linenum:       1.000
    sequence_1:    DEFINE
    sequence_2:    6-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         CYCLE 4 / 1-6;
    req_2:         PCS MODE F / 1-6;
    req_3:         SAME ORIENT FOR 2-6 AS 1;
    req_4:         POS TARG 0., 0.
    comment_1:     THIS SEQUENCE TAKES 6 EXPOSURES
    comment_2:     SPACED AROUND A HEXAGONAL PATH
    comment_3:     WITH 1/2-PIXEL STEPS BETWEN EXPOSURES.

!


    linenum:       2.000
    sequence_1:    DEFINE
    sequence_2:    6-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.023, 0.

!

    linenum:       3.000
    sequence_1:    DEFINE
    sequence_2:    6-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.046, 0.023

!

    linenum:       4.000
    sequence_1:    DEFINE
    sequence_2:    6-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.023, 0.046

!

    linenum:       5.000
    sequence_1:    DEFINE
    sequence_2:    6-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.0, 0.046

!

    linenum:       6.000
    sequence_1:    DEFINE
    sequence_2:    6-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG -0.023, 0.023

!

    linenum:       11.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         CYCLE 4 / 11-18;
    req_2:         PCS MODE F / 11-18;
    req_3:         SAME ORIENT FOR 12-18 AS 11;
    req_4:         POS TARG 0., 0.
    comment_1:     THIS SEQUENCE TAKES 8 EXPOSURES
    comment_2:     SPACED AROUND AN OCTAGONAL PATH
    comment_3:     WITH 1/2-PIXEL STEPS BETWEN EXPOSURES.

!

    linenum:       12.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.023, 0.

!

    linenum:       13.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.046, 0.023

!

    linenum:       14.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.046, 0.046

!

    linenum:       15.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.023, 0.069

!

    linenum:       16.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG 0.0, 0.069

!

    linenum:       17.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG -0.023, 0.046

!

    linenum:       18.000
    sequence_1:    DEFINE
    sequence_2:    8-POSNS
    targname:      #
    config:        WFPC2
    opmode:        IMAGE
    aperture:      PC1-FIX
    sp_element:    #
    num_exp:       1
    time_per_exp:  100S
    fluxnum_1:     1
    priority:      1
    param_1:       CR-SPLIT=NO,
    param_2:       CLOCKS=NO,
    param_3:       ATD-GAIN=7
    req_1:         POS TARG -0.023, 0.023

!

    linenum:       21.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      PAL4-NORTH
    sp_element:    F555W
    time_per_exp:  X14
    req_1:         SAME ORIENT FOR 22 AS 21
    comment_1:     SEQUENCE OF 8 X 1400 SEC V FRAMES

!

    linenum:       22.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      PAL4-NORTH
    sp_element:    F814W
    time_per_exp:  X13
    comment_1:     SEQUENCE OF 8 X 1300 SEC I FRAMES

!

    linenum:       23.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      PAL4-NORTH-OFF
    sp_element:    F555W
    time_per_exp:  X0.6
    req_1:         SAME ORIENT FOR 23-24 AS 21
    comment_1:     SEQUENCE OF 6 X 60 SEC V FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!

    linenum:       24.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      PAL4-NORTH-OFF
    sp_element:    F814W
    time_per_exp:  X0.3
    comment_1:     SEQUENCE OF 6 X 30 SEC I FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!

    linenum:       31.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      PAL4-SOUTH
    sp_element:    F555W
    time_per_exp:  X14
    req_1:         SAME ORIENT FOR 32 AS 31
    comment_1:     SEQUENCE OF 8 X 1400 SEC V FRAMES

!

    linenum:       32.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      PAL4-SOUTH
    sp_element:    F814W
    time_per_exp:  X13
    comment_1:     SEQUENCE OF 8 X 1300 SEC I FRAMES

!

    linenum:       33.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      PAL4-SOUTH-OFF
    sp_element:    F555W
    time_per_exp:  X0.6
    req_1:         SAME ORIENT FOR 33-34 AS 31
    comment_1:     SEQUENCE OF 6 X 60 SEC V FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!

    linenum:       34.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      PAL4-SOUTH-OFF
    sp_element:    F814W
    time_per_exp:  X0.3
    comment_1:     SEQUENCE OF 6 X 30 SEC I FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!

    linenum:       41.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      NGC2419-NORTH
    sp_element:    F555W
    time_per_exp:  X14
    req_1:         SAME ORIENT FOR 42 AS 41
    comment_1:     SEQUENCE OF 8 X 1400 SEC V FRAMES

!

    linenum:       42.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      NGC2419-NORTH
    sp_element:    F814W
    time_per_exp:  X13
    comment_1:     SEQUENCE OF 8 X 1300 SEC I FRAMES

!

    linenum:       43.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      NGC2419-NORTH-OFF
    sp_element:    F555W
    time_per_exp:  X0.6
    req_1:         SAME ORIENT FOR 43-44 AS 41
    comment_1:     SEQUENCE OF 6 X 60 SEC V FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!

    linenum:       44.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      NGC2419-NORTH-OFF
    sp_element:    F814W
    time_per_exp:  X0.3
    comment_1:     SEQUENCE OF 6 X 30 SEC I FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!

    linenum:       51.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      NGC2419-SOUTH
    sp_element:    F555W
    time_per_exp:  X14
    req_1:         SAME ORIENT FOR 52 AS 51
    comment_1:     SEQUENCE OF 8 X 1400 SEC V FRAMES

!

    linenum:       52.000
    sequence_1:    USE
    sequence_2:    8-POSNS
    targname:      NGC2419-SOUTH
    sp_element:    F814W
    time_per_exp:  X13
    comment_1:     SEQUENCE OF 8 X 1300 SEC I FRAMES

!

    linenum:       53.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      NGC2419-SOUTH-OFF
    sp_element:    F555W
    time_per_exp:  X0.6
    req_1:         SAME ORIENT FOR 53-54 AS 51
    comment_1:     SEQUENCE OF 6 X 60 SEC V FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!

    linenum:       54.000
    sequence_1:    USE
    sequence_2:    6-POSNS
    targname:      NGC2419-SOUTH-OFF
    sp_element:    F814W
    time_per_exp:  X0.3
    comment_1:     SEQUENCE OF 6 X 30 SEC I FRAMES, IN
    comment_2:     FIELD OFFSET TO INCLUDE A FEW BRIGHT
    comment_3:     STARS.

!
! end of exposure logsheet

! No scan data records found