This is the Health Check plot for the stability of the GIRAFFE flat field calibration
lamps. The plot is based on ROBOTIC flats (flattype=ROB) taken several times a week.
All 5 fibre systems (on two plates) are illuminated by the same flat lamp.
Since June 2006, the HC flats are measured for all five slit systems.
Before that date, they were taken for Medusa1 and Medusa2 only. </font><p><font size="2">

The average flux is obtained by dividing the average signal in the first raw
file by the EXPTIME.
Any effect showing up in only one fibre system is likely to be
caused by that fibre system. Effects related to the lamp should be visible
in any fibre system in the same way.</font><p><font size="2">

Find more tutorial information <a
href="/qc/GIRAFFE/qc/lamp_qc1.html">here</a>.