! Proposal 6842, submission 1
! PI: John Spencer
! Received Thu Jan 18 17:38:39 EST 1996
! From: mcgrath@stsci.edu
Proposal_Information
              Title: EVOLUTION OF THE NEW BRIGHT SPOT ON IO
  Proposal_Category: GO
Scientific_Category: Solar System
              Cycle: 5

Investigators
        PI_name: John Spencer
 PI_Institution: Lowell Observatory

       CoI_Name: Melissa McGrath
CoI_Institution: Space Telescope Science Institute
        Contact: Y          ! Y or N (designate at most one contact)

       CoI_Name: Alfred McEwen
CoI_Institution: USGS Flagstaff


Abstract:                                ! Free format text (please update)
    We would like to re-observe the new bright spot that we discovered in
HST images of Io taken in July 1995, in order to determine the
evolution of its spectral reflectivity with time.  Observations with
WFPC2 on a single orbit in late Februray or March 1996 would fill a
large time gap between the July 1995 discovery images and the first
Galileo images (and possible Cycle 6 HST images) in July 1996.

Questions                       ! Free format text (please update)

     Observing_Description:
We use one HST orbit to obtain multicolor WFPC2 images of Io, centered
in the PC chip.  The filters to be used are F343N (500s), F375N (500s),
F410M (10s), F467M (3s), F502N (16s), F588N (3s), F658N (6s), and F791W
(2.3s).  For maximum time separation from the planned July 1996 Galileo
images of Io, HST observations should be made as soon as possible after
February 20th 1996, when Jupiter becomes far enough from the Sun for
HST to observe.  Io central longitudes between 300 and 340 degrees are
needed in order to get a good view of the new spot, which is at
longitude 325 degrees (central longitudes must be less than about 340
to avoid eclipses and occultations by Jupiter).


Calibration_Justification:             
      Additional_Comments:


Solar_System_Targets

  Target_Number: 1
    Target_Name: IO-LON320
    Description: SATELLITE IO
        Level_1: STD=JUPITER                       
        Level_2: STD=IO
         Window: OLG OF IO BETWEEN 300 340
                 SEP OF JUPITER IO FROM EARTH GT 5.0"
           Flux: SURF(V)=5.14
                 B-V = 1.2
       Comments: Io should be in full sunlight (not in Jupiter's shadow umbra or penumbra)
                 for all exposures.  Execution as soon as feasible after 20 Febr is highly  
                 desired.


Visits                                  

      Visit_Number: 1
Visit_Requirements:             
        BETWEEN 20-FEB-96 AND 10-MAR-96
  On_Hold_Comments:
    Visit_Comments: Execution as soon as feasible after 20 Febr is highly desired.


     Exposure_Number: 1                  
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F343N
 Optional_Parameters: CR-SPLIT=NO
                      ATD-GAIN=15
Number_of_Iterations: 1
   Time_Per_Exposure: 500S

     Exposure_Number: 2
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F375N
 Optional_Parameters: ATD-GAIN=15                      
Number_of_Iterations: 1
   Time_Per_Exposure: 500S

     Exposure_Number: 3
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F410M
 Optional_Parameters: ATD-GAIN=15                      
Number_of_Iterations: 1
   Time_Per_Exposure: 10S

     Exposure_Number: 4
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F467M
 Optional_Parameters: ATD-GAIN=15                      
Number_of_Iterations: 1
   Time_Per_Exposure: 3.0S

     Exposure_Number: 5
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F502N
 Optional_Parameters: ATD-GAIN=15                      
Number_of_Iterations: 1
   Time_Per_Exposure: 16S

     Exposure_Number: 6
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F588N
 Optional_Parameters: ATD-GAIN=15                      
Number_of_Iterations: 1
   Time_Per_Exposure: 3.0S

     Exposure_Number: 7                  
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F658N
 Optional_Parameters: ATD-GAIN=15                      
Number_of_Iterations: 1
   Time_Per_Exposure: 6.0S

     Exposure_Number: 8
         Target_Name: IO-LON320
              Config: WFPC2
              Opmode: IMAGE
            Aperture: PC1
          Sp_Element: F791W
 Optional_Parameters: ATD-GAIN=15                      
Number_of_Iterations: 1
   Time_Per_Exposure: 0.23S

Data_Distribution
         Medium: 8MM             ! 8MM or 6250BPI or 1600BPI
Blocking_Factor: 10              ! 10 or 1
        Ship_To: PI_Address      ! STSCI or PI_Address or <free-text>
       Ship_Via: UPS             ! UPS (2-day) or OVERNIGHT