!   $Id: 5672,v 8.1 1994/07/27 20:16:03 pepsa Exp $
coverpage:

  title_1:         AGES FOR THE OUTERMOST GLOBULAR CLUSTERS: THE FORMATION
    title_2:       OF THE GALACTIC HALO: CYCLE 4 HIGH, PART II
    sci_cat:       COOL STARS
    sci_subcat:    OLD CLUSTERS
    proposal_for:  GO
    CONT_ID:       5481       ! Previous proposal ID (if continuation), I4
    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 1.5 PC pixels 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.  

!

  question:        3
    section:       2
    line_1:        The telescope will again be moved
    line_2:        about 1.5 pixels 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:        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:       4
    name_1:        PAL4-CENTER
    descr_1:       C,201
    pos_1:         RA = 11H 29M 15.86S +/- 1",
    pos_2:         DEC = +28D 58' 31.2" +/- 1",
    pos_3:         PLATE-ID=019K
    equinox:       J2000
    comment_1:     CENTRAL FIELD IN DISTANT GLOBULAR
    comment_2:     CLUSTER PAL 4
    fluxnum_1:     1
    fluxval_1:     V=25

!

    targnum:       5
    name_1:        PAL3-CENTER
    descr_1:       C,201
    pos_1:         RA = 10H 05M 31.4S +/- 1",
    pos_2:         DEC = +00D 04' 20.8" +/- 1",
    pos_3:         PLATE-ID=00JL
    equinox:       J2000
    comment_1:     CENTRAL FIELD IN DISTANT GLOBULAR
    comment_2:     CLUSTER PAL 3.
    fluxnum_1:     1
    fluxval_1:     V=25

!

! end of fixed targets

! No solar system records found

! No generic target records found

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!

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!

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!

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!

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!

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!

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!
! end of exposure logsheet

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