HAWK-I was commissioned during Periods 79 and 80 and then began operations at the start of P81. Since then it has sufferred to varying degrees from several problems which afect the quality of the data. This page summarizes these problems. Details are provided in spearate web pages. They are linked from this page.

For further description of problems/features visit the History section of the plot_tutorial pages.

All data to date...

• Cosmetic quality: The HAWK-I chips have a number of cosmetic features, which are described in section B.2 of the User's manual.
• Radioactive Events: Chip No. 2 ( #78 ) is subject of charge collection induced by radioactive events (13 events per minute).
• Spider Web Patterns in DARKS: A "spider web" like pattern is clearly seen in CHIP1 DARK frames for DITs less than about 40sec, except when the minimum DIT is used.

Some of the data...

• 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.
• Central Flare-like feature: Intermittently, for periods of months, a flare-like feature appears at the centre of the four chip array, i.e. where the four chips meet each other, see here.

Some of the data...

• Pupil Ghosts: [2008-04-01 and 2008-08-20, i.e. most of P81]
• Wrong CD matrix WCS transformation coefficients: [P81]