Pickup noise from autoguider of +/- 10 counts

The problem is pickup noise from the autoguider on chip 1 and 4. So if the autoguider is off no noise patterns are seen. The magnitude of the effect is +/- 10cts. Using signal we estimate that for typical exposure times (5min.) poisson noise from sky is higher than this effect (in U we get 122 photons/pix). This effect shouldn't be a killer for most science exposures. However narrow band / U imaging of faint extend objets might suffer.
The workaround is to stop guiding when reading out, this can be done by typing:

SYS>guide off
when the ccd starts to read. A more simple procedure is to include in your script the following comand:

SYS>run 500 object &
SYS>sleep 480
SYS>guide off This will ensure that when you are taking the exposure, as soon as reading starts the autoguider is turned off.

----8<--------8<--------8<--------8<--------8<--------8<--------8<--------8<----