| Flag |
Definition and source |
| 0 |
Good pixels |
| 1 |
Reed-Solomon decoding error; e.g. data lost during transmission or compression.
|
| 2 |
Calibration file defect. Set if pixel flagged in any calibration file.
Includes charge transfer traps identified in static pixel mask file (.r0h).
|
| 4 |
Permanent camera defect. Static defects are maintained in the CDBS database and
flag problems such as blocked columns and dead pixels. (Not currently used.)
|
| 8 |
A/D converter saturation. The actual signal is unrecoverable but known to
exceed the A/D full-scale signal (4095).
Calibrated saturated pixels may have values significantly lower than 4095 due to bias
subtraction and flatfielding. In general, data values above 3500 DN are likely saturated.
On-orbit tests have shown that for WFPC2, the conversion values have
remained constant; therefore, the A-to-D reference file contains only
one temperature and one set (row) of conversion values.
|
| 16 |
Missing data. The pixel was lost during readout or transmission. (Not currently used.)
|
| 32 |
Bad pixel that does not fall into above categories.
|
| 128 |
Permanent charge trap. (Not currently used.)
|
| 256 |
Questionable pixel. A pixel lying above a charge trap which may be affected by the trap.
|
| 512 |
Unrepaired warm pixel.
|
| 1024 |
Repaired warm pixel.
|
| 2048 |
Entire chip masked out, e.g. due to WF4 bias anomaly or to exclude PC chip
|
