24 µm Latent Images and Saturated Sources

Principal: Deborah Padgett
Deputy: James Muzerolle
Data Monkey(s):
Priority: Desired
Downlink Priority: Normal
Analysis Time: 48 hours
Last Updated:

Objective

Understand the consequences of observing very bright sources with MIPS

Description

Observations corresponding to 50%, 100%, and 500% of full well will be taken. These saturation levels will be achieved through a combination source selection and exposure times. This activity should be done with both point sources and extended saturating sources, but calculations are based on doing it only with point sources. At each of the three signal levels: (1) Observe a source using a small field dither pattern (1 cycle); (2) Execute a flush cycle (dark sky observation).

Data Collected

This task is accomplished entirely with AORs. We point at Thuban, take a single cycle of 24 µm small field photometry (16 DCEs) with a 3 sec exposure (~30% full well). Then we move to a dark sky region 1 deg N & E of Thuban and perform 3 sec single photometry cycles at two positions offset by 10". We return to Thuban for 10 sec exposures, followed by the 2 dither cycles of 3 sec exposures on dark sky. Finally, we do 30 sec exposure on Thuban with 3 dithered cycles of 3 sec dark sky exposure following. 


#  Please edit this file with care to maintain the
#  correct format so that SPOT can still read it.
#  Generated by SPOT on:  6/12/2002     14:20:31

HEADER: FILE_VERSION=6.1, STATUS = PROPOSAL

      AOT_TYPE:  MIPS Photometry
     AOR_LABEL:  MIPS-155-30%star-3s
    AOR_STATUS:  new

 MOVING_TARGET:  NO
   TARGET_TYPE:  FIXED SINGLE
   TARGET_NAME:  thuban
  COORD_SYSTEM:  Equatorial  J2000
      POSITION:  RA_LON=14h04m23.35s,  DEC_LAT=+64d22m33.1s, PM_RA=-0.057", PM_DEC=0.017"
OBJECT_AVOIDANCE:  EARTH = YES, OTHERS = YES

    MICRON_24: FIELD_SIZE = SMALL, EXPOSURE_TIME = 3, N_CYCLES = 1
SPECIAL_OVERHEAD: IMPACT = none, LATE_EPHEMERIS = NO
RESOURCE_EST: TOTAL_DURATION=296.6, SLEW_TIME=5.4, SETTLE_TIME=5.0, SLEW_OVERHEAD=180.0, SPECIAL_OVERHEAD=0.0, UPLINK_VOLUME=817, DOWNLINK_VOLUME=1041136, VERSION=S6.1.B5
INTEGRATION_TIME: MIPS_24=48.234497,MIPS_70=0.0,MIPS_160=0.0





      AOT_TYPE:  MIPS Photometry
     AOR_LABEL:  MIPS-155-30%sky-3s
    AOR_STATUS:  new

 MOVING_TARGET:  NO
   TARGET_TYPE:  FIXED CLUSTER - OFFSETS
   TARGET_NAME:  thuban-offsets
  COORD_SYSTEM:  Equatorial  J2000
     POSITION1:  RA_LON=14h04m23.35s,  DEC_LAT=+64d22m33.1s, PM_RA=-0.057", PM_DEC=0.017"
     OFFSET_P2:  EAST_ARRAY_V=3600.0",	NORTH_ARRAY_W=3600.0"
     OFFSET_P3:  EAST_ARRAY_V=3570.0",	NORTH_ARRAY_W=3600.0"
OFFSETS_IN_ARRAY:  NO
OBSERVE_OFFSETS_ONLY:  YES
OBJECT_AVOIDANCE:  EARTH = YES, OTHERS = YES

    MICRON_24: FIELD_SIZE = SMALL, EXPOSURE_TIME = 3, N_CYCLES = 1
SPECIAL_OVERHEAD: IMPACT = none, LATE_EPHEMERIS = NO
RESOURCE_EST: TOTAL_DURATION=403.2644, SLEW_TIME=16.4, SETTLE_TIME=17.664415, SLEW_OVERHEAD=180.0, SPECIAL_OVERHEAD=0.0, UPLINK_VOLUME=1172, DOWNLINK_VOLUME=2082272, VERSION=S6.1.B5
INTEGRATION_TIME: MIPS_24=48.234497,MIPS_70=0.0,MIPS_160=0.0





      AOT_TYPE:  MIPS Photometry
     AOR_LABEL:  MIPS-155-100%star-10s
    AOR_STATUS:  new

 MOVING_TARGET:  NO
   TARGET_TYPE:  FIXED SINGLE
   TARGET_NAME:  thuban
  COORD_SYSTEM:  Equatorial  J2000
      POSITION:  RA_LON=14h04m23.35s,  DEC_LAT=+64d22m33.1s, PM_RA=-0.057", PM_DEC=0.017"
OBJECT_AVOIDANCE:  EARTH = YES, OTHERS = YES

    MICRON_24: FIELD_SIZE = SMALL, EXPOSURE_TIME = 10, N_CYCLES = 1
SPECIAL_OVERHEAD: IMPACT = none, LATE_EPHEMERIS = NO
RESOURCE_EST: TOTAL_DURATION=414.6, SLEW_TIME=5.4, SETTLE_TIME=5.0, SLEW_OVERHEAD=180.0, SPECIAL_OVERHEAD=0.0, UPLINK_VOLUME=817, DOWNLINK_VOLUME=2513280, VERSION=S6.1.B5
INTEGRATION_TIME: MIPS_24=165.675,MIPS_70=0.0,MIPS_160=0.0





      AOT_TYPE:  MIPS Photometry
     AOR_LABEL:  MIPS-155-100%sky-3s
    AOR_STATUS:  new

 MOVING_TARGET:  NO
   TARGET_TYPE:  FIXED CLUSTER - OFFSETS
   TARGET_NAME:  thuban-offset
  COORD_SYSTEM:  Equatorial  J2000
     POSITION1:  RA_LON=14h04m23.35s,  DEC_LAT=+64d22m33.1s, PM_RA=-0.057", PM_DEC=0.017"
     OFFSET_P2:  EAST_ARRAY_V=3600.0",	NORTH_ARRAY_W=3600.0"
     OFFSET_P3:  EAST_ARRAY_V=3570.0",	NORTH_ARRAY_W=3600.0"
OFFSETS_IN_ARRAY:  NO
OBSERVE_OFFSETS_ONLY:  YES
OBJECT_AVOIDANCE:  EARTH = YES, OTHERS = YES

    MICRON_24: FIELD_SIZE = SMALL, EXPOSURE_TIME = 3, N_CYCLES = 1
SPECIAL_OVERHEAD: IMPACT = none, LATE_EPHEMERIS = NO
RESOURCE_EST: TOTAL_DURATION=403.2644, SLEW_TIME=16.4, SETTLE_TIME=17.664415, SLEW_OVERHEAD=180.0, SPECIAL_OVERHEAD=0.0, UPLINK_VOLUME=1172, DOWNLINK_VOLUME=2082272, VERSION=S6.1.B5
INTEGRATION_TIME: MIPS_24=48.234497,MIPS_70=0.0,MIPS_160=0.0





      AOT_TYPE:  MIPS Photometry
     AOR_LABEL:  MIPS-155-300%star-30s
    AOR_STATUS:  new

 MOVING_TARGET:  NO
   TARGET_TYPE:  FIXED SINGLE
   TARGET_NAME:  thuban
  COORD_SYSTEM:  Equatorial  J2000
      POSITION:  RA_LON=14h04m23.35s,  DEC_LAT=+64d22m33.1s, PM_RA=-0.057", PM_DEC=0.017"
OBJECT_AVOIDANCE:  EARTH = YES, OTHERS = YES

    MICRON_24: FIELD_SIZE = SMALL, EXPOSURE_TIME = 30, N_CYCLES = 1
SPECIAL_OVERHEAD: IMPACT = none, LATE_EPHEMERIS = NO
RESOURCE_EST: TOTAL_DURATION=748.6, SLEW_TIME=5.4, SETTLE_TIME=5.0, SLEW_OVERHEAD=180.0, SPECIAL_OVERHEAD=0.0, UPLINK_VOLUME=817, DOWNLINK_VOLUME=6719408, VERSION=S6.1.B5
INTEGRATION_TIME: MIPS_24=501.2,MIPS_70=0.0,MIPS_160=0.0





      AOT_TYPE:  MIPS Photometry
     AOR_LABEL:  MIPS-155-300%sky-3s
    AOR_STATUS:  new

 MOVING_TARGET:  NO
   TARGET_TYPE:  FIXED CLUSTER - OFFSETS
   TARGET_NAME:  thuban-3offsets
  COORD_SYSTEM:  Equatorial  J2000
     POSITION1:  RA_LON=14h04m23.35s,  DEC_LAT=+64d22m33.1s, PM_RA=-0.057", PM_DEC=0.017"
     OFFSET_P2:  EAST_ARRAY_V=3600.0",	NORTH_ARRAY_W=3600.0"
     OFFSET_P3:  EAST_ARRAY_V=3570.0",	NORTH_ARRAY_W=3600.0"
     OFFSET_P4:  EAST_ARRAY_V=3600.0",	NORTH_ARRAY_W=3570.0"
OFFSETS_IN_ARRAY:  NO
OBSERVE_OFFSETS_ONLY:  YES
OBJECT_AVOIDANCE:  EARTH = YES, OTHERS = YES

    MICRON_24: FIELD_SIZE = SMALL, EXPOSURE_TIME = 3, N_CYCLES = 1
SPECIAL_OVERHEAD: IMPACT = none, LATE_EPHEMERIS = NO
RESOURCE_EST: TOTAL_DURATION=511.45312, SLEW_TIME=28.2, SETTLE_TIME=32.053127, SLEW_OVERHEAD=180.0, SPECIAL_OVERHEAD=0.0, UPLINK_VOLUME=1506, DOWNLINK_VOLUME=3123408, VERSION=S6.1.B5
INTEGRATION_TIME: MIPS_24=48.234497,MIPS_70=0.0,MIPS_160=0.0





CONSTRAINT: TYPE=CHAIN, NAME=Chain-MIPS-155
AORS: AOR1=MIPS-155-30%star-3s, 
      AOR2=MIPS-155-30%sky-3s, 
      AOR3=MIPS-155-100%star-10s, 
      AOR4=MIPS-155-100%sky-3s, 
      AOR5=MIPS-155-300%star-30s, 
      AOR6=MIPS-155-300%sky-3s

Data Reformatting Requirements

Array Data Desired:

24 µm

Data Reformatting Option:

Special Instructions:

Task Dependencies

Calibration Dependencies

Output and Deliverable Products

The output of this test will be confirmation of the timescales estimated for latent decay from ground test.

Data Analysis

The data analysis for this task requires decent photometry of latent images on the dark sky DCEs. Thus, we will calibrate the data, including replacement of saturated pixels for the Thuban images. Aperture photometry will be performed on the stellar images and latents. Finally, we will make plots demonstrating the decay in latent images with time and fit exponential functions to the curve as in the analysis of Su (2002).

Software Requirements

Actions Following Analysis

The results of this test will validate ground tests on latent decay during flight conditions. In case of significantly different results, a more extensive set of latency tests will be designed and implemented as part of MIPS engineering time. These will provide more data for latency characterization.

Failure Modes and Responses

Most likely failure mode of task is poor S/N or excessive saturation of the stellar images. Another star must be selected in that case, and the test must be repeated. The test may also be invalidated if the dark field is too busy with extragalactic point sources. In that case, the task should be redone using the 24 µm dark position.

Additional Notes