Principal: Chad Engelbracht
Deputy: Dean Hines, Dave Frayer, Doug Kelly, Almudena Alonso, Jeonghee Rho
Data Monkey(s): James Muzerolle, Kate Su, Casey Papovich
Priority: Necessary
Downlink Priority: Normal
Analysis Time: 24h
Last Updated:
This is the 24µm flux calibration to be done at the beginning and end of every campaign after the instrument has been basically checked out and the telescope temperature has stabilized.
This is the standard campaign 24µm flux calibration. 1 flux standard will be observed using 2 cycles of the photometry AOR, using small-field mode and 3-second DCEs. In addition, a short observation of the 24um stimulator (10 DCEs before and after the stellar observation) will be made to calibrate that stimulator and check for stimulator stability. This task is intended to establish the DN to Jy conversion factor for the campaign. Other tasks perform a detailed characterization of the dependence of this factor on integration time (mips-110), background (mips-921), or flux (mips-350).
The AOR takes 349 seconds. The stim IER takes 71 seconds and will be done twice, so the total duration of this task is about 8 minutes. If we have to use a fainter star for calibration, we'll use 10-second DCEs, pushing the total time up to about 13 minutes, a little more than the 11 minutes allotted for this task.
This task will generate 30 observations of the standard star, 14 observations of the stimulator, and 6 dark observations, for a total of 50 DCEs. The stellar and stimulator observations will both be 3-second DCEs. The stimulator observations will be generated using the 24µm stimulator IER (MIPS-IER-120), while the standard star observations will be generated using a standard AOR.
Array Data Desired:
24 µm
Data Reformatting Option:
Special Instructions:
The main goal of the analysis is to determine the flux conversion factor for this campaign. The data will be processed with both the SSC pipeline and the MIPS DAT (using default settings); the derived flux conversion factors will be compared to check for problems in the data processing. To derive the flux conversion factor, photometry will be performed on the star in each of the 30 DCEs. This must be done in such a way that corrects for distortion. The results will be averaged, rejecting any measurement greater than 3 standard deviations from the mean. The assumed flux of the star (from the tables on the MIPS IST web page) will be divided by the measured counts (corrected from the measured aperture to the total star counts using an aperture correction) to compute the flux conversion factor.
A mosaic of the stellar images will be generated. This image will be examined visually for any obvious problems, such as poor matching of background levels between DCEs, missing data, asteroids in the field, etc. Photometry will also be performed on the stellar image and compared to the results derived above. If the flux conversion factors do not match within the errors, a more thorough investigation of the data will be required.
The processed stimulator images will be averaged. If any image deviates by more than 3 standard deviations from the mean, the data will be investigated more thoroughly. If the data are acceptable, the flux conversion factor will be inserted in the header of the stimulator image and the data will be archived and made available to the IT/IST.
If the standard anomaly response actions do result in usable data, calibration can still be achieved using the redundant set of observations at the beginning or end of the campaign.