IRAC High Precision Photometry
MISSDATA, MISS_LCT
Dataset:
55cnc
r48070144 frame 353 and 6399
Symptoms:
Shows up as a position problem. The header is the key that tells me there is something wrong.
Explanation
MISSDATA = T and MISS_LCT GT 0
This frame is missing data.
These images should not be included in the analysis.
BADTRIG
Dataset:
55cnc
r48072960
images: 7950, 5259, 9256, among others
Symptoms:
Centroids of whole images are off in x.
Explanation:
In the headers BADTRIG is set, and ZEROPIX is gt 1 (often ~4800). An occasional problem is observed during the warm mission wherein an extra byte appears in the science packet (image data). As a result, all pixels after this byte are shifted by one pixel. Such images are identified by having the ABADDATA header keyword set in the raw data (BADTRIG in the BCD images); the images themselves usually become stripy as a result of the mismatch between the science and calibration data. The SSC pipeline corrects this by locating the first pixel in the image with a value of exactly 0, and then shifting all later pixels.
In the case of these images, there is more than one ZEROPIX, so the pipeline cannot correct the images for the shift in pixels.
These images should not be included in the analysis.
Figure 1: Left side vertical axis is for the grey lines and wheel speed RPM. The right side vertical axis corresponds to X (blue) and Y(green) centroids of the AOR as a function of SCLK_time. BADTRIG is set for the X positions which have centroids of 15.5 after sclk_time of 1.058017E9.