QC PLOTS
	CURRENT	HISTORY
imaging lamps
QC1 database (advanced users): browse | plot
spectroscopic lamps
QC1 database (advanced users): browse | plot
Click on CURRENT to see the current trending (Health Check).    Click on HISTORY to see the historical evolution of the trending.

QC1 parameters

• efficiency (QC1 database table fors2_scrflat, column efficiency)
  This is the median signal of the first raw frame devided by exposure time. The median value is computed within a window 250x150 pixel chosen close to the gap region between the 2 CCDs to minimize the illumination gradient. This is only a nominal 'efficiency' actually measuring the stability of exposure level (influenced by e.g. aging of lamps etc.).

Trending

History

• 2010-12-01 FlatBlue+1 lamp replaced
• 2010-11-04 new FlatBlue+1 lamp saturates imaging screen flats
• 2010-10-19 FlatBlue+1 lamp replaced
• 2010-08-25 FlatBlue+1 lamp replaced
• Trending of the old FORS2 CCD (until 2002-03-31) can be found here.

QC1 parameters

• lamp flux (QC1 database table fors2_lamp_chk, column flux)
  This parameter is determined from a bias-subtracted calibration lamp exposure in LSS mode. After background subtraction the total signal is integrated and normalized by the exposure time and the total number of original CCD pixels (keeping into account possible binning). The background is evaluated from the available overscan regions.

Trending

For trending we use only data obtained with the 300V grism with the GG435 filter and a 1" slit, using the standard resolution collimator.

History

• 2010-12-01 FlatBlue+1 lamp replaced
• 2010-10-19 FlatBlue+1 lamp replaced
• 2010-08-25 FlatBlue+1 lamp replaced
• 2010-02-11 Exposure times for FlatBlue+4 were reduced by 20%, thresholds were accordingly raised by 25%