Proposal_Information
              Title: The Extreme Ultraviolet Spectrum of a High-Redshift Quasar
  Proposal_Category: GTO/FOS
Scientific_Category: QSO
              Cycle: 5

Investigators
        PI_name: Arthur F. Davidsen
 PI_Institution: Johns Hopkins University

       CoI_Name: Holland C. Ford
CoI_Institution: Johns Hopkins University

       CoI_Name: Richard Harms
CoI_Institution: Applied Research Corporatio

       CoI_Name: Edward Beaver
CoI_Institution: University of California, San Diego

       CoI_Name: E. Margaret Burbidge
CoI_Institution: Univeristy of California, San Diego

       CoI_Name: Frank Bartko
CoI_Institution: Applied Research Corporation

       CoI_Name: Bruce Margon
CoI_Institution: University of Washington

       CoI_Name: J. Roger P. Angel
CoI_Institution: University of Arizona

       CoI_Name: Ralph Bohlin
CoI_Institution: Space Telescope Science Institute

Abstract:
We will observe the far-UV spectrum of the z=2.36 QSO SBS1542+541 to measure the shape
of the extreme ultraviolet continuum, measure Lyman alpha forest lines, and to measure
metal line absorption systems.  The absorption line measurements will be used to
ascertain the physical characteristics of any intervening absorbers.  The Lyman alpha
forest measurements in particular will be used in conjunction with data obtained with
the Hopkins Ultraviolet Telescope during the Astro-2 mission to constrain the physical
state of the Lyman alpha clouds and the intergalactic medium.  These data may also
constrain the shape and the intensity of the meta-galactic UV ionizing background
radiation at high redshift.


Questions

Observing_Description:
The QSO will be observed with the high resolution UV gratings using both the red and
the blue sides of the FOS.  Starting on the red side, a binary target acquisition will
be used to place the quasar in the 0.86 arc sec circular aperture (B-3).  A 1600 s
integration using grating G270H will be obtained.  The target will then be transferred
to the blue side, and 14880 s of data will be obtained using grating G130H followed by
a 5040 s integration using grating G190H.  This set of integrations should fit into 9
orbits, between SAA passes.  If the program must be shortened to 8 orbits to fit
between SAA's, the G130H integration should be changed to 12320 s.


Fixed_Targets
  Target_Number: 1
    Target_Name: SBS1542+541
    Description: GALAXY, QSO
       Position: RA=15H 43M 59.40S +/- 0.01S,
                 DEC=+53D 59' 3.3" +/- 0.1",
                 PLATE-ID=01BT
        Equinox: 2000
        RV_or_Z: Z=2.371
           Flux: V=17.15 +/- 0.2,
                 B-V=0.16


Visits
Visit_Number: 1

     Exposure_Number: 1
         Target_Name: SBS1542+541
              Config: FOS/RD
              Opmode: ACQ/BINARY
            Aperture: 4.3
          Sp_Element: MIRROR
Number_of_Iterations: 1
   Time_Per_Exposure: 17.4S
Special_Requirements: ONBOARD ACQ FOR 2-4

     Exposure_Number: 2
         Target_Name: SBS1542+541
              Config: FOS/RD
              Opmode: ACCUM
            Aperture: 1.0
          Sp_Element: G270H
Number_of_Iterations: 1
   Time_Per_Exposure: 1600S

     Exposure_Number: 3
         Target_Name: SBS1542+541
              Config: FOS/BL
              Opmode: ACCUM
            Aperture: 1.0
          Sp_Element: G130H
Number_of_Iterations: 1
   Time_Per_Exposure: 14880S
            Comments: 14880S is the integration time to fit in 9 orbits.  12320S is the
                      integration time to fit in 8 orbits.

     Exposure_Number: 4
         Target_Name: SBS1542+541
              Config: FOS/BL
              Opmode: ACCUM
            Aperture: 1.0
          Sp_Element: G190H
Number_of_Iterations: 1
   Time_Per_Exposure: 5040S


Data_Distribution                      
         Medium: 8MM            
Blocking_Factor: 10             
        Ship_To: PI_Address     
       Ship_Via: UPS