Eliminating Crosstalk: 2009-05-07

• Elimination of crosstalk
• Reduction of Readout Noise
• Increase in minimum DIT (from 1.2572 to 1.6762 seconds)

• Crosstalk between amplifiers: [All data prior to 2009-05-07, i.e. all periods prior to, plus part of P83] Crosstalk between the amplifiers of the chips produces a series of 'crater-like' artifacts arrayed horizontally with respect to each 'bright' star in the field.
  By adjusting certain voltages of the detector electronics this effect has been virtually eliminated. In addition this change reduced the Readout Noise of the detectors, but increased the minimum-DIT from 1.2572sec to 1.6762sec. This change was applied at approximately 2009-05-07T21:30.
• Change of the detector read speed 2009-05-07 : The HAWKI detector read speed has been changed for reasons to reduce the electronic ghosts.

  Before 2009-05-07T21:30 it was:

  HIERARCH ESO DET VOLT1 DC6   = 2.4000 / Set value DC-Voltage
  HIERARCH ESO DET VOLT1 DC7   = 3.4000 / Set value DC-Voltage
  HIERARCH ESO DET RSPEED      = 6 / Read-Speed Factor
  HIERARCH ESO DET MINDIT      = 1.2572000 / Minimum DIT                
  

  From 2009-05-07T021:30 on it is:

  HIERARCH ESO DET VOLT1 DC6   = 2.1000 / Set value DC-Voltage
  HIERARCH ESO DET VOLT1 DC7   = 3.6000 / Set value DC-Voltage
  HIERARCH ESO DET RSPEED      = 8 / Read-Speed Factor
  HIERARCH ESO DET MINDIT      = 1.6762000 / Minimum DIT     
  

  Consider 2009-05-07T21:30 as a breakpoint to associate calibrations. Do not use twlight flats or darks acquired before 2009-05-08 to calibrate science data acquired after 2009-05-08 and vice-versa.