RE: [alma-sw-ssr] Offline and Pipeline Requirements

[mel wright 456 <wright@astron.berkeley.edu>]

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Tim,

	It's good to have your participation, and know what
to expect.

If there is a significant increase in image fidelity by
going back to the uv-data in the deconvolution of mosaiced
images, then this has a very significant effect on the operational
model for ALMA image analysis.

It remains to be demonstrated that there is a meaningful
increase in image fidelity with telescopes with real pointing
and other errors, and what the cost in performance is.

These tests should be done as soon as possible, and I would be happy
to provide some data. The attached MIRIAD script, takes
about 5 min to make images, 10 min for SDI and 20 min for Maxen
on a sun ultra 10 (93000 uv-points and 19 pointings and 64 channels).
 The numbers can be scaled appropriately for ALMA.

		cheers,

			Melvyn

> > 
> > The calibration and imaging, of course require the uv-data,
> > but almost all deconvolution algorithms do not.
> 
> FYI, this used to be true before the advent of mosaicing but now
> many of the highest quality deconvolution algorithms require
> going back to the original data in a minor cycle/major cycle
> mode.
> 
> In any event, I've sufficiently abused my lurker status that I'll
> shut up now.
> 
> Regards,
> 
> Tim
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#!/bin/csh

# multichannel mosaic imaging using MIRIAD
rm -r hcn.mp hcn.bm 
invert vis=@hcn.data map=hcn.mp  beam=hcn.bm  line=channel,64,1,1,1 options=mosaic,double,systemp imsize=194 cell=1.4 robust=0.5 

# SDI deconvolution
rm -r hcn.sdi  hcn.sdicm
mossdi map=hcn.mp  beam=hcn.bm    out=hcn.sdi  niters=100 'region=image(2,64)'
restor map=hcn.mp  beam=hcn.bm  model=hcn.sdi  out=hcn.sdicm

# Maximum entropy deconvolution
rm -r hcn.mem  hcn.memcm
mosmem map=hcn.mp  beam=hcn.bm    out=hcn.mem  niters=50 'region=image(2,64)'
restor map=hcn.mp  beam=hcn.bm  model=hcn.mem  out=hcn.memcm

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