Changes to NIRC2 FITS Header

When NIRC2 data are prepared for inclusion into the archive, about 20 new keywords are added to the FITS header to provide additional information about the sky position, weather, wavelengths, and observing program. An error in this preparation code was discovered that formatted several of these keyword values (see below for the list) as string values rather than numerical values. This format error causes certain IDL programs (like the FITS file viewer ATV) to fail because the KOA-added World Coordinate System (WCS) header keyword values are not in the expected and proper format. The common FITS viewer DS9 can read in these FITS files and display sky coordinates based on the WCS, but shows 'nan' for the "Physical" pixel coordinates.

As of 29 September 2014, all NIRC2 headers in the archive have had this error fixed and are correctly read and interpreted by FITS reading software. If you have downloaded NIRC2 from KOA prior to 29 September 2014 and are negatively impacted by this error, then we encourage you to re-download the corrected data files. You could also try to fix the formats of these keywords (listed below) using whatever software with which you are most comfortable (eg., python, IDL, WCStools). The data values for these keywords are valid; only the format is incorrect.

The header keywords whose values were changed from string to numeric values are

WAVEBLUE
WAVECNTR
WAVERED
PIXSCALE
PIXSCAL1
PIXSCAL2
CRPIX1
CRPIX2
LTM1_1
LTM2_2
CD1_1
CD1_2
CD2_1
CD2_2
WXDOMHUM
WXDOMTMP
WXOUTHUM
WXOUTTMP
WXPRESS

We apologize for any inconvenience this error may have caused. Please contact the KOA Helpdesk if you require further information or help.

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).

\#koashare.html\

+ 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	Changes to NIRC2 FITS Header When NIRC2 data are prepared for inclusion into the archive, about 20 new keywords are added to the FITS header to provide additional information about the sky position, weather, wavelengths, and observing program. An error in this preparation code was discovered that formatted several of these keyword values (see below for the list) as string values rather than numerical values. This format error causes certain IDL programs (like the FITS file viewer ATV) to fail because the KOA-added World Coordinate System (WCS) header keyword values are not in the expected and proper format. The common FITS viewer DS9 can read in these FITS files and display sky coordinates based on the WCS, but shows 'nan' for the "Physical" pixel coordinates. As of 29 September 2014, all NIRC2 headers in the archive have had this error fixed and are correctly read and interpreted by FITS reading software. If you have downloaded NIRC2 from KOA prior to 29 September 2014 and are negatively impacted by this error, then we encourage you to re-download the corrected data files. You could also try to fix the formats of these keywords (listed below) using whatever software with which you are most comfortable (eg., python, IDL, WCStools). The data values for these keywords are valid; only the format is incorrect. The header keywords whose values were changed from string to numeric values are WAVEBLUE WAVECNTR WAVERED PIXSCALE PIXSCAL1 PIXSCAL2 CRPIX1 CRPIX2 LTM1_1 LTM2_2 CD1_1 CD1_2 CD2_1 CD2_2 WXDOMHUM WXDOMTMP WXOUTHUM WXOUTTMP WXPRESS We apologize for any inconvenience this error may have caused. Please contact the KOA Helpdesk if you require further information or help.

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\