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NICMOS Proposing Example - 4

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!  | PED OUTPUT PRODUCT |
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!
!  /data/charon4/smov/1033.prop
!  Generated by PREPROCESSOR, version 7.0
!  Date: Wed Dec 18 10:44:36 EST 1996

Proposal_Information
              Title: NICMOS Imaging of Circumstellar Material
  Proposal_Category: GO
Scientific_Category: STELLAR EJECTA
              Cycle: 7


Investigators

            PI_Name: Joan Smith
     PI_Institution: University 1


           CoI_Name: John Brown
    CoI_Institution: University 2
            Contact: 


Abstract:
Strategy for Point Spread Function (PSF) subtraction. Circumstellar objects
without using the coronograph.


Questions


    Observing_Description:
In this proposal, circumstellar material is being observed in NIC2 and
the F160W filter. The central star is so bright that its core will be
saturated in 0.1 seconds, much less than the minimum exposure time
allowed by NICMOS in the MULTIACCUM readout mode (0.204 seconds). The
use of the coronograph is NOT suitable for this observation, because
the material is located at a distance of less than 0".4 (the effective
radius of the NICMOS coronographic spot). In order to get enough
signal-to-noise on the circumstellar material, long exposures are
required.  The NICMOS detectors do not suffer from bleeding, and the
central object can be allowed to saturate without compromising the
observations. The MULTIACCUM readout mode with the sequence STEP256 and
NSAMP=12 (corresponding to 512 seconds of integration) is used to
obtain enough dynamical range and signal-to-noise ratio on the
circumstellar material. For the PSF subtraction two steps are needed:
1) exposures of the central star with the BRIGHTOBJ mode to obtain
unsaturated images and determine its centroid; these exposures must be
obtained back-to-back with each primary MULTIACCUM exposure, since
they must be obtained in the same detector's position; 2) observations
with the same instrument configuration of a nearby isolated star, to
determine the PSF. The "PSF" star is selected to be a couple of
magnitudes fainter than the primary target so unsaturated images will
be obtained with the MULTIACCUM sequence 1CAMRR and NSAMP=2.  Each
exposure series will be repeated to reach fainter brightness limits for the
circumstellar material (as an example, we will repeat the observation
twice); to avoid potential problems related to image persistence on
the detector, a POS TARG maneuver of 5" will be implemented between
exposure series to place the target on another detector position.

  Real_Time_Justification:


Calibration_Justification:


      Additional_Comments:



Fixed_Targets

  Target_Number: 1
    Target_Name: BRIGHTSTAR
Alternate_Names: Nice Star 1
    Description: STAR
       Position: RA=13H 50M 49.40S +/- 0.02S,DEC=42D 20' 58.0" +/- 0.7"
        Equinox: J2000
        RV_or_Z: 
          RA_PM: 0.0
         Dec_PM: 0.0
          Epoch: 
Annual_Parallax: 0.0
           Flux: 
                F(1.60)=0.00
       Comments: The value of the flux is in units of Jy, at 1.6 microns. The star is very bright

  Target_Number: 2
    Target_Name: PSFSTAR
Alternate_Names: Nice Star 2
    Description: STAR
       Position: RA=13H 50M 49.40S +/- 0.02S,DEC=42D 48' 58.0" +/- 0.7"
        Equinox: J2000
        RV_or_Z: 
          RA_PM: 0.0
         Dec_PM: 0.0
          Epoch: 
Annual_Parallax: 0.0
           Flux: 
                F(1.60)=0.00
       Comments: The value of the flux is in units of Jy, at 1.6 microns. This is the PSF star.


Solar_System_Targets


Generic_Targets


Scan_Data


Visits

      Visit_Number: 01
Visit_Requirements: 
  On_Hold_Comments: 
    Visit_Comments: Two targets will be visited.

     Exposure_Number: 1
         Target_Name: BRIGHTSTAR
              Config: NIC2
              Opmode: MULTIACCUM
            Aperture: NIC2
          Sp_Element: F160W
          Wavelength: 
 Optional_Parameters: SAMP-SEQ=STEP256,NSAMP=12
Number_of_Iterations: 1
   Time_Per_Exposure: DEF
Special_Requirements: 
            Comments: 

     Exposure_Number: 2
         Target_Name: BRIGHTSTAR
              Config: NIC2
              Opmode: BRIGHTOBJ
            Aperture: NIC2
          Sp_Element: F160W
          Wavelength: 
 Optional_Parameters: 
Number_of_Iterations: 1
   Time_Per_Exposure: 0.050176 S
Special_Requirements: 
            Comments: 

     Exposure_Number: 3
         Target_Name: BRIGHTSTAR
              Config: NIC2
              Opmode: MULTIACCUM
            Aperture: NIC2
          Sp_Element: F160W
          Wavelength: 
 Optional_Parameters: SAMP-SEQ=STEP256,NSAMP=12
Number_of_Iterations: 1
   Time_Per_Exposure: DEF
Special_Requirements: POS TARG 5, 5 
            Comments: 

     Exposure_Number: 4
         Target_Name: BRIGHTSTAR
              Config: NIC2
              Opmode: BRIGHTOBJ
            Aperture: NIC2
          Sp_Element: F160W
          Wavelength: 
 Optional_Parameters: 
Number_of_Iterations: 1
   Time_Per_Exposure: 0.050176 S
Special_Requirements: POS TARG 5, 5
            Comments: 

     Exposure_Number: 5
         Target_Name: PSFSTAR
              Config: NIC2
              Opmode: MULTIACCUM
            Aperture: NIC2
          Sp_Element: F160W
          Wavelength: 
 Optional_Parameters: SAMP-SEQ=SCAMRR,NSAMP=2
Number_of_Iterations: 1
   Time_Per_Exposure: DEF
Special_Requirements: 
            Comments: 

     Exposure_Number: 6
         Target_Name: PSFSTAR
              Config: NIC2
              Opmode: MULTIACCUM
            Aperture: NIC2
          Sp_Element: F160W
          Wavelength: 
 Optional_Parameters: SAMP-SEQ=SCAMRR,NSAMP=2
Number_of_Iterations: 1
   Time_Per_Exposure: DEF
Special_Requirements: POS TARG 5, 5
            Comments: 

Data_Distribution         ! Defaults indicated; change if desired

         Medium: 8MM
        Ship_To: PI_Address
Recipient_Email: 

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