Hubble Space Telescope
Phase II Example: NICMOS Parallel Observations

NICMOS Parallel Observations

NICMOS cameras can be operated in parallel with each other. However, doing so may require serial dumps of the memory buffer which will cost on target time. Also, due to the NICMOS dewar anomaly, the three cameras are not parfocual -- that is, they are not in focus at a common PAM position. The focus positions for Cameras 1 and 2 are very close to each other, and when operated in parallel with each other, Cameras 1 and 2 will produce acceptable images. The intermediate PAM position provides a compromise focus position for Cameras 1 and 2, optional parameter CAMERA-FOCUS = 1-2.

The focus position for Camera 3 is far from the focus position for Cameras 1 and 2. When Camera 3 is operated in parallel to Cameras 1 and 2, star images in Camera 3 will look like donuts, and vice versa. The following is an example of specifying "PARallel" observations on the Phase II exposure line. For this example, Camera 1 is prime and Camera 2 is operated in parallel. It is recommended that the exposure times of parallel observations be shorter than the primary science observation.

Note: Since Cycle 7 and 7N, the NICMOS commanding has been changed so that a camera not used in parallel with a prime camera will be set into mode that will not produce "Electronic Bars."

     Exposure_Number: 10
         Target_Name: NGC6681
              Config: NIC1
              Opmode: MULTIACCUM
            Aperture: NIC1-FIX
          Sp_Element: F170M
          Wavelength: 1.70
 Optional_Parameters: SAMP-SEQ=STEP8,NSAMP=9
Number_of_Iterations: 1
   Time_Per_Exposure: DEF
Special_Requirements: PAR 11,12 WITH 10
            Comments: exp=31.963s


     Exposure_Number: 11
         Target_Name: ANY
              Config: NIC2
              Opmode: MULTIACCUM
            Aperture: NIC2
         Sp_Element: F160W
          Wavelength: 1.600
 Optional_Parameters: SAMP-SEQ=STEP1,NSAMP=7
Number_of_Iterations: 1
   Time_Per_Exposure: DEF
Special_Requirements:
            Comments: exp=4.987s


     Exposure_Number: 12
         Target_Name: ANY
              Config: NIC2
              Opmode: MULTIACCUM
            Aperture: NIC2
          Sp_Element: F171M
          Wavelength: 1.71
 Optional_Parameters: SAMP-SEQ=STEP8,NSAMP=8
Number_of_Iterations: 1
   Time_Per_Exposure: DEF
Special_Requirements:
            Comments: exp=23.969s