Why Aren't Extracted Spectra Available?

The automated reduction pipeline has been designed to handle a wide variety of observing modes and astronomical objects. As a result, the data reduction pipeline can not properly extract 100% of the data. At times, this results in a complete reduction of the CCD order with individual orders that have failed as indicated in our Pass/Fail grading system. In other cases, an entire CCD may have failed and produced no output at all, or the reduction may have proceeded partially and ended prematurely. The lack of a KOA extracted specrum or preview does not necessarily mean the raw data are not scientifically valid, but rather the KOA automatic data reduction pipeline did not complete.

The absence of a preview image may be the result of a variety of causes including (but not limited to):

Sometimes raw images, or subsets of them, were never intended for spectral extraction. This could be the case, for instance, when an observer is interested in the red parts of the spectrum, and uses a slit length that is optimal for those wavelengths, while allowing orders in the blue to overlap.
If there are two or more objects on the slit at the same time, it is unclear which object was intended for reduction.
The data reduction pipeline was optimized for the extraction of point sources. A spectrum of an extended object that fills the slit requires significantly different extraction techniques, possibly causing the pipeline to fail.
The original observer may have failed to take appropriate calibration data. This sometimes occurs when the data were not meant for science (e.g. a test exposure to get a quick subjective feel for the target's spectrum), or the observer simply made a mistake.

In some cases, intermediate reduction files may still be available even if the entire process did not complete. Even if no preview images are available, you may be able to retrieve some extracted products in your download package by choosing to "Include Extracted Spectra" when you select files for download. Please see "KOA Extracted Spectra Products for more detail on the contents of download packages.

For more information, please see Guide to Interpreting the Extracted Spectra or Why Makee Fails.

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	Why Aren't Extracted Spectra Available? The automated reduction pipeline has been designed to handle a wide variety of observing modes and astronomical objects. As a result, the data reduction pipeline can not properly extract 100% of the data. At times, this results in a complete reduction of the CCD order with individual orders that have failed as indicated in our Pass/Fail grading system. In other cases, an entire CCD may have failed and produced no output at all, or the reduction may have proceeded partially and ended prematurely. The lack of a KOA extracted specrum or preview does not necessarily mean the raw data are not scientifically valid, but rather the KOA automatic data reduction pipeline did not complete. The absence of a preview image may be the result of a variety of causes including (but not limited to): Sometimes raw images, or subsets of them, were never intended for spectral extraction. This could be the case, for instance, when an observer is interested in the red parts of the spectrum, and uses a slit length that is optimal for those wavelengths, while allowing orders in the blue to overlap. If there are two or more objects on the slit at the same time, it is unclear which object was intended for reduction. The data reduction pipeline was optimized for the extraction of point sources. A spectrum of an extended object that fills the slit requires significantly different extraction techniques, possibly causing the pipeline to fail. The original observer may have failed to take appropriate calibration data. This sometimes occurs when the data were not meant for science (e.g. a test exposure to get a quick subjective feel for the target's spectrum), or the observer simply made a mistake. In some cases, intermediate reduction files may still be available even if the entire process did not complete. Even if no preview images are available, you may be able to retrieve some extracted products in your download package by choosing to "Include Extracted Spectra" when you select files for download. Please see "KOA Extracted Spectra Products for more detail on the contents of download packages. For more information, please see Guide to Interpreting the Extracted Spectra or Why Makee Fails.

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\