STScI Logo

Hubble Space Telescope
Revisions to the Data Quality flags for calcos

The spatial Data Quality (DQ) flag assignments used by calcos were redefined on March 10, 2010 with the delivery of a new FUV bad pixel table (DHB Section 3.7.8). The new assignments can be found on the web at http://www.stsci.edu/hst/cos/pipeline/cos_dq_flags. This table supersedes Tables 2.16 and 3.10 in the COS Data Handbook. Additional redefinitions are expected with the release of calcos 2.13 in STSDAS and OPUS by the end of the year. The redefinitions associated with calcos 2.13 will be announced in a future STAN.

In addition, the default value of the header keyword SDQFLAGS (DHB Section 3.4.13) was changed from 184 to 188 for FUV data in early March 2010 with the installation of OPUS 2010.1b . Previously, detector edges, dead spots, hot spots, and out-of-bounds regions were excluded when the x1dsum spectra were constructed. Now, grid wire positions join this list. For FUV observations with multiple FP-POS positions this removes the regularly spaced grid wire shadows from the x1dsum spectra, with the caveat that the S/N will be reduced at these locations.

Section 3.4.12 of the COS Data Handbook describes how calcos uses the data quality flags for both TIME-TAG and ACCUM data.