! Proposal 6282, submission 1
! PI: WESTPHAL, JAMES
! Received Sun Apr  9 21:07:48 EDT 1995
! From: spe@hellas.gps.caltech.edu
Proposal_Information

   Title:               STELLAR POPULATIONS IN DWARF SPHEROIDAL GALAXIES -
                        DRACO AND URSA MINOR
   Proposal_Category:   GTO/WFC
   Scientific_Category: GALAXIES & CLUSTERS
   Cycle:               5


Investigators

   PI_name:             WESTPHAL, JAMES  
   PI_Institution:      CALTECH

Questions
   Observing_Description:  A single, one-orbit, dark-time exposure with the 
                           WFC is desired in each of filters F555W and F814W  
                           for each field, plus shorter exposures for cosmic 
                           ray removal and calibration of brighter stars. One 
                           field per galaxy.  Targets for current observing 
                           period: Ursa Minor, Draco (Cycle 5).
   Real_Time_Justification:
   Calibration_Justification:
   Additional_Comments:    HR diagrams are proposed of dwarf spheroidal 
                           galaxies using the WFC and filters F555W and F814W. 
                           Studies include the age and stellar metallicity
                           distributions, distance moduli, luminosity functions,
                           and stellar mass-to-light ratios. One field in Ursa 
                           Minor and Draco is planned.


Abstract:     HR diagrams to deep levels using the F555W and F814W  filters and
              the WFC will be used to study the stellar populations of the 
              dwarf spheroidal galaxies Carina, Ursa Minor and Fornax. Aspects 
              to be studied include the star formation histories based on the 
              location and distribution of stars near the main-sequence turnoff;
              the luminosities, colors, and metallicities of stars on the giant
              branch; the relation of horizontal-branch morphology to stellar 
              ages and metallicities; distance moduli via main sequence fitting;
              the absolute magnitude of the horizontal branch; the main-
              sequence luminosity function; the possible incidence of binaries 
              on the main sequence; and an estimate of the overall mass-to-light
              ratio and space density of baryonic matter in stars. In Fornax, 
              the proposed field also contains the metal-poor cluster Fornax 4,
              whose HR diagram and radial density gradient will also be 
              measured.


Fixed_Targets

   Target_Number:       1
   Target_Name:         URSA-MINOR
   Alternate_Names:     
   Description:         GALAXY,DWARF SPHEROIDAL
   Position:            RA=15H 07M 55.6S +/- 0.3S,
                        DEC= +67D 23' 44" +/- 5"
   Equinox:             B1950
   Flux:                V = 18.1,
                        V-I = 0.55
   Comments:            PRETTY DIFFUSE DWARF GALAXY

!   Target_Number:       2
!   Target_Name:         DRACO
!   Alternate_Names:     
!   Description:         GALAXY,DWARF SPHEROIDAL
!   Position:            RA=17H 19M 21.8S +/- 0.3S,
!                        DEC= +57D 57' 36" +/- 5"
!   Equinox:             B1950
!   Flux:                V = 17.5,
!                        V-I = 0.55
!   Comments:            PRETTY DIFFUSE DWARF GALAXY


Visits

Visit_Number:           01
Visit_Requirements:     

   Exposure_number:     10
   Target_Name:         URSA-MINOR
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            WFALL
   Sp_Element:          F555W
   Number_of_iterations:1
   Time_Per_Exposure:   200S
   Optional_Parameters: CR-SPLIT=NO, ATD-GAIN=15
   Special_Requirements: NO SPLIT

   Exposure_number:     20
   Target_Name:         URSA-MINOR       
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            WFALL  
   Sp_Element:          F555W
   Number_of_iterations:1
   Time_Per_Exposure:   1000S
   Optional_Parameters: CR-SPLIT=NO
   Special_Requirements: SAME POS AS 10
                         NO SPLIT

   Exposure_number:     30
   Target_Name:         URSA-MINOR       
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            WFALL  
   Sp_Element:          F555W
   Number_of_iterations:1
   Time_Per_Exposure:   1100S
   Optional_Parameters: CR-SPLIT=NO
   Special_Requirements: SAME POS AS 10
                         NO SPLIT

   Exposure_number:     40
   Target_Name:         URSA-MINOR       
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            WFALL  
   Sp_Element:          F814W
   Number_of_iterations:1
   Time_Per_Exposure:   200S
   Optional_Parameters: CR-SPLIT=NO, ATD-GAIN=15
   Special_Requirements: SAME POS AS 10
                         NO SPLIT

   Exposure_number:     50
   Target_Name:         URSA-MINOR       
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            WFALL  
   Sp_Element:          F814W
   Number_of_iterations:1
   Time_Per_Exposure:   1200S
   Optional_Parameters: CR-SPLIT=NO
   Special_Requirements: SAME POS AS 10
                         NO SPLIT

   Exposure_number:     60
   Target_Name:         URSA-MINOR       
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            WFALL  
   Sp_Element:          F814W
   Number_of_iterations:1
   Time_Per_Exposure:   1100S
   Optional_Parameters: CR-SPLIT=NO
   Special_Requirements: SAME POS AS 10
                         NO SPLIT


!Visit_Number:           02
!Visit_Requirements:     
!
!   Exposure_number:     10
!   Target_Name:         DRACO
!   Config:              WFPC2
!   Opmode:              IMAGE
!   Aperture:            WFALL
!   Sp_Element:          F555W
!   Number_of_iterations:1
!   Time_Per_Exposure:   200S
!   Optional_Parameters: CR-SPLIT=NO, ATD-GAIN=15
!   Special_Requirements: NO SPLIT
!   Comments:            CYCLE 5 PROPOSAL  2/8/95  RML
!
!   Exposure_number:     20
!   Target_Name:         DRACO       
!   Config:              WFPC2
!   Opmode:              IMAGE
!   Aperture:            WFALL  
!   Sp_Element:          F555W
!   Number_of_iterations:1
!   Time_Per_Exposure:   2000S
!   Optional_Parameters: CR-SPLIT=0.5, CR-TOLERANCE=0.0
!   Special_Requirements: SAME POS AS 10
!                         NO SPLIT
!
!   Exposure_number:     30
!   Target_Name:         DRACO       
!   Config:              WFPC2
!   Opmode:              IMAGE
!   Aperture:            WFALL  
!   Sp_Element:          F814W
!   Number_of_iterations:1
!   Time_Per_Exposure:   200S
!   Optional_Parameters: CR-SPLIT=NO, ATD-GAIN=15
!   Special_Requirements: SAME POS AS 10
!                         NO SPLIT
!
!   Exposure_number:     40
!   Target_Name:         DRACO       
!   Config:              WFPC2
!   Opmode:              IMAGE
!   Aperture:            WFALL  
!   Sp_Element:          F814W
!   Number_of_iterations:1
!   Time_Per_Exposure:   2200S
!   Optional_Parameters: CR-SPLIT=0.5, CR-TOLERANCE=0.0
!   Special_Requirements: SAME POS AS 10
!                         NO SPLIT

Data_Distribution                  
         Medium:        8MM         
Blocking_Factor:        10          
        Ship_To:        PI_address
       Ship_Via:        UPS         
Recipient_Email:        !jaw@sol1.gps.caltech.edu