!   $Id: 6324,v 2.1 1995/07/21 12:18:12 pepsa Exp $
Proposal_Information

   Title:               PARALLAX OF GEMINGA
   Proposal_Category:   GO/DD
   Scientific_Category: HOT STARS,NEUTRON STARS
   Cycle:               5


Investigators

   PI_name:             Giovanni Bignami
   PI_Institution:      Istituto per Richerche in Fisica
   CoI_Name:            Patrizia Caraveo
   CoI_Institution:     Istituto per Richerche in Fisica
   Contact:             Y
   CoI_Name:            Laurence Taff
   CoI_Institution:     JHU
  


Questions

   Observing_Description:  Director's Discretionary Program to obtain 
3 additional orbits of data on Geminga.  WFPC2 images will be
taken in the F555W filter.  Observations are best obtained at equinox so 
preferred date is 21 September.  Have included time window of 18 to 24
September to be more flexible.  An orient is also specified to ensure data
are obtained at the same orient as those taken last September in 5751 -- 
SU 01.

Abstract: The object orignally known as G" was proposed as the optical 
counterpart of the source Geminga on the basis of its colour peculiarities.  
The discovery of its proper motion strongly supported such identification by 
giving to it the characteristics of a neutron star.  Fixing the distance to 
Geminga by measuring the annual parallax of its optical counterpart became a 
real possibility only at the HST refurbishing mission.  

Fixed_Targets

   Target_Number:       1
   Target_Name:         STAR-0633+1746
   Alternate_Names:     GEMINGA,1E0630+178
   Description:         STAR,PULSAR,
   Position:            RA=6H 33M 54.13S +/- 0.033S,
                        DEC= 17D 46' 12.43" +/-  0.50",
                        PLATE-ID=001S
   Equinox:             J2000
   Epoch:               
   Rv_or_z:             
   RA_PM:               0.0
   Dec_PM:              0.0
   Annual_Parallax:     0.0
   Flux:                E(B-V) = 15.0 E-2,
                        V = 25.3 +/- 0.2,
                        B = 26.5 +/- 0.5
   Comments:            



Visits

Visit_Number:           01
Visit_Requirements:     BETWEEN 18-SEP-1995 AND 24-SEP-1995;
			ORIENT 272D TO 273D;
On_Hold_Comments:       
visit_comments:  Prefer 21 September at equinox scheduling.
   ! From Line 3
   Exposure_number:     10
   Target_Name:         STAR-0633+1746
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            PC1
   Sp_Element:          F555W
   Wavelength:          
   Optional_Parameters: CR-TOLERANCE=0.0
   Number_of_iterations:1
   Time_Per_Exposure:   1400S
   Special_Requirements:
   Comments:            

   ! From Line 3.5
   Exposure_number:     20
   Target_Name:         STAR-0633+1746
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            PC1
   Sp_Element:          F555W
   Wavelength:          
   Optional_Parameters: CR-TOLERANCE=0.0
   Number_of_iterations:1
   Time_Per_Exposure:   1600s
   Special_Requirements:
   Comments:            

   ! From Line 4
   Exposure_number:     30
   Target_Name:         STAR-0633+1746
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            PC1
   Sp_Element:          F555W
   Wavelength:          
   Optional_Parameters: CR-TOLERANCE=0.0
   Number_of_iterations:1
   Time_Per_Exposure:   1600s
   Special_Requirements:
   Comments:            

   Exposure_number:     40
   Target_Name:         STAR-0633+1746
   Config:              WFPC2
   Opmode:              IMAGE
   Aperture:            PC1
   Sp_Element:          F675W
   Wavelength:          
   Optional_Parameters: CR-SPLIT=NO
   Number_of_iterations:3
   Time_Per_Exposure:   800s
   Special_Requirements:
   Comments:            


Data_Distribution

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