160micron Routine Photometry Illumination Correction (IC)

Principal: Almudena Alonso
Deputy: David Frayer
Data Monkey(s): Almudena Alonso, David Frayer, Eiichi Egami
Priority:
Downlink Priority: Normal
Analysis Time: 24-48 hours
Last Updated:

Objective

To obtain a 160micron Routine Photometry IC

Description

We will obtain IOC acceptable routine 160um PHOTOMETRY mode ICs (this task is repeated a number of times in different IOC campaigns) to be used on a regular basis. This activity is a companion to the 160 um routine SCAN IC task (MIPS-916). The pair of activities will allow us to determine the relative efficiency and quality of ICs created using scan and photometry AORs.

Since this task is repeated a number of times during IOC, we will observe different regions of the sky each time. The task will check for possible variations of quality of IC or saturation. This task will also be useful for screening regions of the sky to obtain ICs in SIRTF routine operations. This task together with MIPS-916 will determine whether routine ICs will be obtained in photometry or scan mode.

This task is executed in:

    MIPS Campaign H
    MIPS Campaign J
    MIPS Campaign K

Data Collected

A 3x3 square dither map (1 cycle) will be obtained at 160micron with 3 second DCEs in a region of the sky chosen to avoid bright point sources. The offsets are 300 arcseconds. At each position there will be 12 images, so a total of 108 images will be obtained each time this task is executed. The map will require about 21.0 minutes of observing time. This is the AOR file overlaid on the sky:




#  Please edit this file with care to maintain the
#  correct format so that SPOT can still read it.
#  Generated by SPOT on:  8/15/2002     11:40:21

HEADER: FILE_VERSION=6.1, STATUS = PROPOSAL

      AOT_TYPE:  MIPS Photometry
     AOR_LABEL:  MIPS-919-Feb07-Mar22
    AOR_STATUS:  new

 MOVING_TARGET:  NO
   TARGET_TYPE:  FIXED CLUSTER - OFFSETS
   TARGET_NAME:  MIPS-919-Feb07-Mar22
  COORD_SYSTEM:  Equatorial  J2000
     POSITION1:  RA_LON=5h19m37.9036s,  DEC_LAT=+03d54m01.4538s
     OFFSET_P2:  EAST_ARRAY_V=300.0",   NORTH_ARRAY_W=0.0"
     OFFSET_P3:  EAST_ARRAY_V=300.0",   NORTH_ARRAY_W=300.0"
     OFFSET_P4:  EAST_ARRAY_V=0.0",     NORTH_ARRAY_W=300.0"
     OFFSET_P5:  EAST_ARRAY_V=-300.0",  NORTH_ARRAY_W=300.0"
     OFFSET_P6:  EAST_ARRAY_V=-300.0",  NORTH_ARRAY_W=0.0"
     OFFSET_P7:  EAST_ARRAY_V=-300.0",  NORTH_ARRAY_W=-300.0"
     OFFSET_P8:  EAST_ARRAY_V=0.0",     NORTH_ARRAY_W=-300.0"
     OFFSET_P9:  EAST_ARRAY_V=300.0",   NORTH_ARRAY_W=-300.0"
OFFSETS_IN_ARRAY:  NO
OBSERVE_OFFSETS_ONLY:  NO
OBJECT_AVOIDANCE:  EARTH = YES, OTHERS = YES

   MICRON_160: FIELD_SIZE = SMALL, EXPOSURE_TIME = 3, N_CYCLES = 1
SPECIAL_OVERHEAD: IMPACT = none, LATE_EPHEMERIS = NO
RESOURCE_EST: TOTAL_DURATION=1301.8495, SLEW_TIME=117.0, SETTLE_TIME=117.74944, 
SLEW_OVERHEAD=180.0, SPECIAL_OVERHEAD=0.0, UPLINK_VOLUME=4756, DOWNLINK_VOLUME=9
370224, VERSION=S6.1.2
INTEGRATION_TIME: MIPS_24=0.0,MIPS_70=0.0,MIPS_160=6.291456

COMMENT_START: 
COMMENT_END:

Data Reformatting Requirements

Array Data Desired:

All Arrays

Data Reformatting Option:

NORMAL

1 FITS file per AOR per array.

Special Instructions:

Task Dependencies

CAID and title of Precedent Task #1 (or None)
etc.

Calibration Dependencies

Dark

Output and Deliverable Products

Mosaic of observed region.

160micron IC obtained in PHOTOMETRY mode.

An IC will be applied to a star observed at different positions across the array to check the quality of the IC. We will provide an array map showing the location dependences -if any- of the photometric sensitivity.

Once the MIPS-916 task (Routine Scan IC at 160micron) is executed, we will provide a detailed comparison between ICs obtained in Photometry and Scan modes at 160micron.

Data Analysis

Standard Pipeline reduction using the DAT and/or SSC Pipeline. If using the DAT, we will run MIPS_SLOPER and then we will do the dark subtraction with MIPS_CALER.
Produce a mosaic of observed region using MIPS_ENHANCER.
Median combine 108 images (with some rejection algorithm) using the IRAF "imcombine" task to create an IC. Alternatively, once the IC DCEs are screened for possible saturation, etc, we can use the MIPS_ENHANCER to create the flatfield frame using an appropriate rejection algorithm.
Apply IC to star observations at different positions across the array (NEED TO DETERMINE IOC TASKS ADEQUATE FOR THIS)
Aperture photometry on star using the IRAF "phot" task to measure flux
Comparison of star aperture photometry at different positions across the array to determine IC accuracy.
Once the task is executed more than once:

we can look for possible IC variations with time/region of sky used
we can determine the number of DCEs necessary to construct a 'super' IC (see J. Stansberry simulations; NEED TO ADD LINK TO FLATFIELD MODEL WEBPAGE).
IMPORTANT NOTE: According to John's simulations we will need approximately 500 DCEs to get an IC with accuracy of 1% (rms, over the whole array), so this task needs to be executed at five times.

Once MIPS-916 is executed, we will carry out a detailed comparison between ICs created in photometry and scan modes.

Software Requirements

DAT
IRAF
IDL

Actions Following Analysis

If the IC S/N and quality requirements are met, the IC frame will be put in the calibration data requirement. Note that according to our simulations this task will have to be repeated more than once before we achieve the desired requirements.

Failure Modes and Responses

If region of the sky used is saturated, this region will be removed from the list of flatfield/IC regions (Jeonghee Rho's list of flatfield/IC regions). This task is repeated a number of times with different regions of the sky, so it should be possible to obtain 160micron ICs. If regions used are all saturated, we will look for different regions of the sky.