inaccuracies in lwimager specification via browser / cattery

[twillis449]

So I just tried for the first time to make a dirty image via the 'imaging options' that appears via turbo-sim.py. There I'm offered the options of specifying the image size in pixels and the image size in arcmin. Since lwimager wants the cell separation in arcsec, you divide image size(arcmin) / image size in pixels. In the particular case I had I specified 13.65 / 2048-> cell size of 3.999999 arcsec (or thereabouts - anyway marginally less than the 0.4 arcsec I wanted.) This meant that the lwimager called via turbo-sim calculated that a point source situated several hundred pixels from the field centre had a flux density of 4.78 units vs 4.74 when lwimager was directly specified via the command line with a cellsize of 0.4 arcsec. Since I'm trying to 'compete' in an SKA gridding competition I though I had discovered a CASA bug until I looked at the exact spec fed into the lwimager.

Could you please add an option to specify cell size directly so as to override the calculation done above? Thanks!