Extracted Spectra Grades

The extracted spectra provided as a browse product represent the result of automatic processing through one particular data reduction tool, MAKEE. In general, human operators of such reduction tools can do a better job of spectral extraction than an automated pipeline, and hence, we strongly recommend that archive users who wish to make serious scientific use of the data should download the raw images and reduce the data themselves, taking particular care that the reduction parameters do not compromise the science that they hope to glean from the data.

Nevertheless, extractions by the pipeline can be quite good. In order to interpret the quality of the extractions, KOA also has an automated "quality assessment" (QA) grade. Again, the automated nature of this grading process is imperfect, so even the grade may not be correct in the archive. Grading is done order-by-order, and the large number of orders in the archive discourage manual grading of each order.

The automatic QA grade is either "Pass", "Fail" or "Unknown." A "Pass" means that reduction artifacts, while they may be present, do not obscure the underlying astronomical data. A "Fail" means that no sign of the underlying data is visible in the extraction; it is dominated by reduction artifacts. "Unknown" means that a QA grade could not be determined. Grades are included in the EXQUAL FITS header keyword.

Grades represent the quality of the extraction, not necessarily the quality of the original data.

Figure 1: Automated grading of a subset of HIRES extractions shows that 93% of the extractions are good, and correctly graded. Another 2% are bad extractions, but also correctly graded. The remaining 5% are incorrectly graded by the automatic algorithm.

Please see Guide to Interpreting the Extracted Spectra for more information on spectra quality.

For a thorough description of the quality assessment procedures, see Quality Assessment of KOA HIRES Extracted Spectra (PDF).

Please acknowledge the use of KOA by including this text in your publications:

This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration.

Please also acknowledge the PI(s) of datasets that have been obtained through KOA, and please contact the KOA Help Desk if you publish archival data.

If your research uses data reduced by the DEIMOS DRP or MOSFIRE DRP, please use the PypeIt Citation.

The Keck Observatory Archive (KOA) is a collaboration between the NASA Exoplanet Science Institute (NExScI) and the W. M. Keck Observatory (WMKO). NExScI is sponsored by NASA's Exoplanet Exploration Program, and operated by the California Institute of Technology in coordination with the Jet Propulsion Laboratory (JPL).

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+ Getting Started + KOA Search Form + KOA and Python + KI Search Form + Publicly Available Data + Contributed Datasets + KOA User Guide + Image API + Reducing Keck Data + KOA Helpdesk + KOA News + Related Archives + Login / Logout	Extracted Spectra Grades The extracted spectra provided as a browse product represent the result of automatic processing through one particular data reduction tool, MAKEE. In general, human operators of such reduction tools can do a better job of spectral extraction than an automated pipeline, and hence, we strongly recommend that archive users who wish to make serious scientific use of the data should download the raw images and reduce the data themselves, taking particular care that the reduction parameters do not compromise the science that they hope to glean from the data. Nevertheless, extractions by the pipeline can be quite good. In order to interpret the quality of the extractions, KOA also has an automated "quality assessment" (QA) grade. Again, the automated nature of this grading process is imperfect, so even the grade may not be correct in the archive. Grading is done order-by-order, and the large number of orders in the archive discourage manual grading of each order. The automatic QA grade is either "Pass", "Fail" or "Unknown." A "Pass" means that reduction artifacts, while they may be present, do not obscure the underlying astronomical data. A "Fail" means that no sign of the underlying data is visible in the extraction; it is dominated by reduction artifacts. "Unknown" means that a QA grade could not be determined. Grades are included in the EXQUAL FITS header keyword. Grades represent the quality of the extraction, not necessarily the quality of the original data. Figure 1: Automated grading of a subset of HIRES extractions shows that 93% of the extractions are good, and correctly graded. Another 2% are bad extractions, but also correctly graded. The remaining 5% are incorrectly graded by the automatic algorithm. Please see Guide to Interpreting the Extracted Spectra for more information on spectra quality. For a thorough description of the quality assessment procedures, see Quality Assessment of KOA HIRES Extracted Spectra (PDF).

Please acknowledge the use of KOA by including this text in your publications: This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. Please also acknowledge the PI(s) of datasets that have been obtained through KOA, and please contact the KOA Help Desk if you publish archival data. If your research uses data reduced by the DEIMOS DRP or MOSFIRE DRP, please use the PypeIt Citation. Privacy Policy Image Use Policy The Keck Observatory Archive (KOA) is a collaboration between the NASA Exoplanet Science Institute (NExScI) and the W. M. Keck Observatory (WMKO). NExScI is sponsored by NASA's Exoplanet Exploration Program, and operated by the California Institute of Technology in coordination with the Jet Propulsion Laboratory (JPL). KOA WMKO \#koashare.html\