24µm Focal Plane Survey, Fine

Principal: Jocelyn Keene
Deputy: Jane Morrison, Bill Wheaton
Data Monkey(s): Jane Morrison, Bill Wheaton
Priority: Necessary
Downlink Priority: Normal
Analysis Time: Campaign Q: 2880 minutes, Campaign R: 2880 minutes, analysis of combining Campagin Q and Campaign R: 120 minutes
Last Updated:


Objective

To measure the pixel locations (i.e. array orientation, scale, and distortion) as a function of scan mirror angle for the 24µm array to an accuracy of 0.14 arc secs. This will allow us to determine the mapping of the celestial coordinates to pixel coordinates.

Description

Use an IER based on the 24 µm photometry compact source AOT to measure the locations on the sky of several positions on the array as a function of scanning mirror angle.
This task is run twice in both campaigns Q and R. The two run for each campaign are processed by the MIPS team and one data set per campaign is set to the IPF team for analysis. The IPF team run each data set seperately and then combines the results from both campaigns. The results from the IPF multi-run are used to update Frame Table 14. The frame table updates for all the campaigns can be found in the following table:
Frame Table Updates.

Data Collected

The IER is very similar to the one for the 24µm coarse Survey. The only difference is the mirror positions chosen map out more of the array. Also for the fine survey the IER is repeated twice. Each IER collects 336 DCEs. Therefore the total number of observations will be 672.

Calibration Star

See IER for the star chosen. This star was chosen as the 24 µm focal plane calibrator based on the following requirements:

  • Star needs to used as the PCRS star as well as the MIPs focal plane star. Note that PCRS stars have a V magnitude between 7-10 (this catalog is based on the Tycho and Hipparcos stars).
  • In CVZ
  • MIPs requirements: stellar brightness corresponding to S/N of 30 (3 sec integrations) at least 14 mJy, K mag 6.53 (range 14 to 500 mJy or K = 6.5 to 1.3)

    Observing Strategy


    Figure 1. Observing Pattern at 3 locations on the detector. Note size of box is not the total size of the array but a portion of the central region which depends on array and if it is a coarse or fine survey

    Definitions:

  • W axis direction is defined by the Frame Table, and is always within +/- 90 degrees of the TPF z axis as projected on the sky. Motion along this axis corresponds to motion in the spacecraft motion (left/right).
  • V axis direction is defined by the Frame Table, and is always within +/- 90 degrees of the TPF y axis as projected on the sky. Motion along this axis corresponds to motion in the scan mirror direction (up/down).
  • W offset, the amount of motion in the W direction which results in the spacing between left array, middle array and right array observations
  • V offset, the amount of motion in the V direction which occurs between a set of observations.

    24 µm Fine FPS observational parameters:

  • W offset = 138 arc seconds
  • V offset = 69 arc seconds
  • W dither = 3.75 arc seconds
  • V dither = 3.75 arc seconds
  • mirror locations for 1 position shown in figure 1.
    1. position 1 = 0
    2. position 2 = -75
    3. position 3 = 25
    4. position 4 = -50
    5. position 5 = 50
    6. position 6 = -25
    7. position 7 = 75
    8. position 8 = position 1 = 0

    Observational Strategy

  • Step 1
    1. PCRS observation
  • Step 2
    1. Position the telescope so the data falls on the left side of array
    2. Take 8 DCES at positions shown in figure 1 (left)
    3. dither in V and W
    4. Take 8 DCES at positions shown in figure 1 (left)
  • Step 3
    1. Move the space craft according to the W offset (138 arc seconds), image should now be on the center of the array.
    2. Take 8 DCES at positions shown in figure 1 (middle)
    3. dither in V and W
    4. Take 8 DCES at positions shown in figure 1 (middle)
  • Step 4
    1. Move the space craft according to the W offset (138 arc seconds), image should now be on the right side of the array.
    2. Take 8 DCES at positions shown in figure 1 (right)
    3. dither in V and W
    4. Take 8 DCES at positions shown in figure 1 (right)
  • Step 5
    1. PCRS observation
  • Step 6: move telescope according to V offset (69 arc seconds) and repeat steps 1-5
  • Step 7: move telescope according to V offset (69 arc seconds) and repeat steps 1-5
  • Step 8: move telescope according to V offset (69 arc seconds) and repeat steps 1-5
  • Step 8: move telescope according to V offset (69 arc seconds) and repeat steps 1-5
  • Step 9: move telescope according to V offset (69 arc seconds) and repeat steps 1-5
  • Step 10: move telescope according to V offset (69 arc seconds) and repeat steps 1-5

    Number of observations from step 1-5, 48. Step 1-5 repeated 7 times for a total of (48 * 7) = 336 observations. For the fine survey this set of observations is repeated a second time for a total of 672 observations.

    
    

    Data Reformatting Requirements

    Array Data Desired:

    24 µm

    Data Reformatting Option:


    Task Dependencies


    Calibration Dependencies


    Output and Deliverable Products


    Data Analysis


    Software Requirements


    Actions Following Analysis


    Failure Modes and Responses

    1. Failure of one campaign (Q or R) to produce useful data
      • If one of the runs looks bad, then go back and analyze the data better. We may need to plot the data to look for bad data, we may need to edit the CA file and resend it to the IPF team.
      • We might need to ask the IPF team to look closer at their analysis.
      • If one set is bad and can not be fixed, then use data from other campaign, if data appear reasonable and change is not large?
    2. Results of Q & R inconsistent, neither obviously bad, then average the results.
    3. Both results are bad - then reschedule observations.

    Additional Notes