Short Description of ‘The SIKKEMA* Set’ Gert Sikkema, Kapteyn Institute, Groningen * Surname of a Phd student who has now quite some experience with the 'The System‘.

WFI Pilot Project by P. Heraudeau -) 18 WFI pointings, 4 square degree; ~1000 redshifts from 2dfGRS. -) Limiting mags in V,R,I: 25, 24.5, 24.5 mag/arcsec^2: ss. -) Observations in OMEGACAM observation mode: Polar fields bad (use only OBJECT=‘2df*’ and ‘STD’) V band not photometric. Observing a 2dfGRS region in VRI. WFI pilot project

Data Reductions )can do all reductions within a week -) readnoise, bias, cold, hot pixels, dome, twilight, master flat, cosmics, straightforward -) pay attention to: overscan correction: method 8. -) pay VERY MUCH attention to time stamps. -)I sometimes gave quality flags to data (bad from logs)  not used -) easy to use: DB viewer and CalTS more sophisticated and sometimes more trustworthy: calls from prompt. -) did global photometry writing my own scripts in awe -) BACKGROUND subtraction to do structural analysis. Past: Change SExtractor values BACK_SIZE and BACK_FILTERSIZE in code Now: new background subtraction method……….

Problems not adressed with my data set: BACKGROUND problem for moderately crowded fields or large objects..