Sequencer Site SIRTF IOC Activity c. 2002

CAID: MIPS-138 Title: 70 um NF Focal Plane Survey (Fine)
 
System: MIPS Principal: jkeene Deputy: 
Objective:   
To measure the pixel locations ( i.e., array orientation, scale and distortion) as a function 
of scan mirror angle for the 70 um narrow field array configuration to an accuracy of 
1.1 arcsec relative to the PCRS.
 
Description: 
Use the 70 um super-resolution AOT to measure the locations on the sky of several 
positions on the array as a function of scanning mirror angle.  

1)   Adjust the IPPs to position the two extreme images (#1 and #S; see Figure 8-26 
      in the SIRTF Observer's Manual V.2.1) at the extremes of the allowable mirror 
      deflections with the remaining images evenly spaced between them. In this figure, 
      the uppermost image is off the array. Hereafter I call it #S.
2)   Set the S/C offset between AOT halves to be slightly less than half of the array width. 
3)   Perform a PCRS peak-up with the star on PCRS 1.
4)   Offset the star to PCRS 2 and make a measurement.
5)   Offset the star so that the central image (#7) is near but within the lower left-hand
      corner of the array. 
6)   Execute the AOT and repeat steps 3 & 4.
7)   Offset the star so that image #7 is at the center and near but within bottom edge of 
      the array. 
8)   Execute the AOT and repeat steps 3 & 4.
9)   Offset the star so that image #7 is near but within the upper left of the array.
10) Execute the AOT and repeat steps 3 & 4.
11) Offset the star so that image #7 is near but within the center top of the array.
12) Execute the AOT and repeat steps 3 & 4.
13) Offset the star so that image #7 is near the middle of the array.
14) Execute the AOT and repeat steps 3 & 4. 
15) Offset the star so that the lowest image (#1) is near but within the lower left-hand 
      corner of the array. 
16) Execute the AOT and repeat steps 3 & 4.
17) Offset the star so that image #1 is near but within the center bottom of the array. 
18) Execute the AOT and repeat steps 3 & 4.
19) Offset the star so that image #1 is near but within the upper left of the array.
20) Execute the AOT and repeat steps 3 & 4.
21) Offset the star so that image #1 is near but within the center top of the array.
22) Execute the AOT and repeat steps 3 & 4.
23) Offset the star so that image #1 is near the middle of the array.
24) Execute the AOT and repeat steps 3 & 4. 
25) Offset the star so that the uppermost image (#S) is near but within the lower left-hand 
      corner of the array. 
26) Execute the AOT and repeat steps 3 & 4.
27) Offset the star so that image #S is near but within the center bottom of the array. 
28) Execute the AOT and repeat steps 3 & 4.
29) Offset the star so that image #S is near but within the upper left of the array.
30) Execute the AOT and repeat steps 3 & 4.
31) Offset the star so that image #S is near but within the center top of the array.
32) Execute the AOT and repeat steps 3 & 4.
33) Offset the star so that image #S is near the middle of the array.
34) Execute the AOT and repeat steps 3 & 4.
 
Day:   81.3138888888934 Suggested Order:   V300
 
Must be preceded by these activities (list by CAID):   MIPS-137
 
Place in Schedule:   The telescope must be focussed. The S/C must be pointing and tracking optimally. The PCS, PCRS, and IRU must be calibrated. The 70 um array and scan mirror must be fully operational. The 70 um super-resolution AOT must be validated. The MIPS should have been turned on for at least 6 hours before this measurement so that the pointing performance is optimized.
 
Priority:   Desired

Conditions

Maximum telescope temperature: 12 K
 
Minimum telescope temperature: 5.5 K
 
Should activity be repeated if focus changes?   No     Repeat if focus changes by 0 mm
 
Maximum absolute pointing uncertainty: 3 arcsec (1 sigma radial)
 
Maximum precision offset uncertainty: 0.4 arcsec  (1 sigma radial)
 
Observatory configuration: IPP files must be adjusted to optimize the scan mirror motion and image placement.
 
Go/No Go criteria: The telescope must be focussed. The S/C must be pointing and tracking optimally. The

Resources

Duration:   260 minutes
 
Real time downlink:   No   

Data Volume (uncompressed): 35.9 Mbits
 
List Blocks, AORs, SERs, IERs, or unique sequences required (uplink): 70 um PT/SR AOT with modified IPP files.
 
List Analysis tools required (downlink):   Standard data reduction software (e.g., IRAF) for centroiding star images. Specialized software for calculating transformation of pixel number and mirror angles into location on sky.

Outcome

Estimate of data turn around:   48 hours
 
Description: Maps of the pixel locations as a function of scan mirror angle.
 
Can proceed in parallel with other activity: No
 
Must outcome be confirmed before next activity: No
 
Method of Confirmation:   Examination of data.
 
 
Success criteria: 1) Star images visible. 2) Sufficient S/N in each image (>30) to centroid each image to better than 0.1 pixel. 3) Redundant data give consistent results.
 
Contingency plan:  Repeat with different stars, integrating longer, using different S/C offsets, IPP files.
 
 

Comments

 
References:  
 
Additional Comments:
The same procedure will be used for the coarse and fine focal plane mappings. It may be repeated to achieve the accuracy needed for the fine survey.
 
This activity last updated: 1/2/2002 5:42:37 PM