Instrumental Signature Analyses

Instrumental Signature FNAL meeting info

Star flat


  • Non-linear crosstalk - Kerstin Paech's results on crosstalk.
  • Kerstin's update at LBL collaboration meeting Apr 2013 here

Low-light-level Nonlinearities

High-light-level nonlinearity

Flux-dependent PSF, a.k.a. brighter-fatter

PSF wings


Bad pixels

Flat-field and fringe frames


Dome offsets and flat fields

  • Dome offsets and flat fields - DJJ and WCW study of flat fields and small offsets in the dome alignment. Thought to be a problem pre-March 2013

u-band LED flat field degredation

  • u-band LED flat field degredation - It has been noticed that throughout Year 1, the LED illumination in u-band LED flat fields has degraded where the levels recorded in mid-Jan 2014 are only about 20% of the values of the beginning of Sept 2013. The file OneLEDataTime.pdf shows the results of a study where a special run by DJJ et al (see elog 156461, for instance). In short, the degradation appears to be due to the individual degradation of especially two of the four stations, but all stations have degraded as well.