sdqflags -- serious data quality flags
This task computes the sum of the data quality flag values (bit mask) for the specified conditions, and the sum is assigned to the parameter value. If verbose=yes, the sum is also printed.
There is an SDQFLAGS keyword in the SCI extension headers of STIS data. This keyword serves to indicate to calstis which data quality conditions are considered by the user to be "serious." This is a bit mask with a default value of 32767, all bits set (the sign bit is not used). The purpose of the sdqflags task is to help the user find the appropriate value for the SDQFLAGS keyword.
Some of the descriptions were copied from the HST Data Handbook, Table 20.8.
- (softerr = no) [boolean]
- Reed-Solomon decoding error. Value = 1.
- (datalost = no) [boolean]
- Data were lost (e.g. due to a problem in telemetry) and were replaced by a fill value. Value = 2.
- (detectorprob = no) [boolean]
- Bad detector pixel (e.g. bad column) or beyond aperture. Value = 4.
- (datamasked = no) [boolean]
- Masked by occulting bar. Value = 8.
- (hotpix = no) [boolean]
- Hot pixel, a pixel with a dark count rate greater than five standard deviations above the median dark level. Value = 16.
- (largeblem = no) [boolean]
- Large blemish, sensitivity (relative to nearby pixels) less than 0.4. Value = 32.
- (overscan = no) [boolean]
- Can be used for finding bias level. (This flag is not currently used.) Value = 128.
- (satpixel = no) [boolean]
- Saturated pixel. For the CCD, this means that the pixel value is greater than the value in the SATURATE column in the CCD parameters table (CCDTAB). For the MAMAs, this means that the pixel value is greater than the value in the LOCAL_LIMIT column in the MAMA linearity table (MLINTAB), or that it is within EXPAND low-res pixels of such a pixel (where EXPAND is a column in the MLINTAB). Value = 256.
- (calibdefect = no) [boolean]
- Bad pixel in reference file. Value = 512.
- (smallblem = no) [boolean]
- Small blemish, sensitivity (relative to nearby pixels) between 0.4 and 0.7. Value = 1024.
- (x1d_bad_background = no) [boolean]
- During 1-D spectral extraction, more than 30% of background pixels were either rejected by sigma-clipping or were already flagged as bad. Value = 2048.
- (x1d_discarded = no) [boolean]
- During 1-D spectral extraction, one or more pixels in the extraction region were discarded. Value = 4096.
- (datareject = no) [boolean]
- Rejected during image combination for cosmic ray rejection. Value = 8192.
- (not_cti_corr = no) [boolean]
- Pixel not CTI corrected. This means that (if cticorr is perform) the gross counts in a pixel were less than or equal to zero, so the CTI correction was not applied to that pixel.
- (b= no) [boolean]
- Not assigned.
- (verbose = yes) [boolean]
- The default is to print value, the sum of the data quality flags.
- (value = 0) [integer]
- This value is assigned by the task; the user should not set it. This is the sum of the data quality values, the bitwise logical OR of all the flags specified.
This task was written by Phil Hodge.