[alma-config] Difference images for the simulations using the SIL

[Steven]

Hello. Of late I have been wondering what the requirements, and indeed
definitions, are for fractional difference maps using the CLEAN images and
convolved models. More immediately my concern has been how to even create
simple subtractive difference maps for array resolutions other than A, where
the model and final CLEANed image are different sizes and have different
pixel scales. Registration of these maps has proved problematic due to
downsampling, windowing etc., and to show where I am at, I have put together
a page on my website which demonstrates the current state of the art
graphically. This may be found by following a link in the 8th November news
item at the top of my usual index page at
http://www.stevenheddle.co.uk/ALMA/ALMA_IND.HTM

I would be grateful if you could have a look at it.

Cheers,
    Steven