STScI Logo

Hubble Space Telescope
WFC3 Crosstalk

Crosstalk in WFC3

Crosstalk in UVIS detectors

Crosstalk in the WFC3/UVIS CCD detectors occurs when a source in one quadrant generates an electronic mirror-image negative ghost in the neighboring quadrant on the same chip. The crosstalk is at a level of about -2 e-04 in quadrants B and D due to sources in A and C and at a level of about -0.7 e-04 for crosstalk in quadrants A and C due to sources in B and D (ISR 2009-03).

A standalone IDL procedure is available for correcting UVIS data for crosstalk, effectively restoring pixels to a mean which is well within 1 sigma of the mean of surrounding pixels. The code as well as a description of its use is available as part of ISR 2012-02, available as a pdf or included in a zip download with a sample data set.

Crosstalk in IR detectors

Crosstalk effects have been observed in the IR channel. Positioned symmetrically opposite the source about the dividing line between each of the coupled readout amplifier quadrants, IR crosstalk appears at a lower level than the surrounding background, about ~1e -06 that of the source signal. The level is low enough that it should not be an issue for most programs; dithering can help mitigate the effect. There is no code for correcting IR images for crosstalk. More details of the IR crosstalk are available in ISR 2010-02.