NExScI Keck Interferometer

This page details specific issues for data calibration and intrepretation for KI by observing run.

• Jul 2008 - Aug 2009 -- V2 SPR configuration
For commissioning data obtained in the Self-Phase Referencing (ASTRA-SPR) configuration (period 2008116 to 2009197 or July 1 2008 to August 1 2009), the wavelength calibration for the data currently stored in the KI Database should not be assumed to be better than about 1%. If your science program requires more accurate wavelength calibration please contact your contact scientist or write to the Help Desk.


• Aug 2007 - present
Bias in visibility amplitude with flux levels has been quantitifed. When corrected (in wbCalib/nbCalib) both the WL and spectral channels for data from 2003 onwards have a absolute systematic bias of less than 0.03 in squared visibility amplitude and the 10 and 42 channel modes have a channel-to-channel systematic of 0.01.


• Jul 2003 - present
  1. Spectrometer well aligned.
  2. Two of the three fringe tracking issues resolved.
  3. Phase dither added to minimize systematics.
  4. Data accuracy 0.05.


• Jan - May 2003
  1. Use spectrometer data from these dates with caution, the spectrometer was aligned, but not in a repeatable fashion.
  2. Fringe data are affected by a software tracking issue which introduces a possible systematic effect of ~5%. See the clock memo for more details.


• Jun - Nov 2002
  1. DO NOT use spectrometer data from these dates, the spectrometer was not aligned.
  2. Fringe data are affected by a software tracking issue which introduces a possible systematic effect of ~5%. See the clock memo for more details.


• June - Sep 2002

  Single telescope flux data was taken only for K2. The ratio correction was constructed from this measurement plus FOREGROUND data.

Last update July 26, 2010

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