Date: 2 Oct 2001
Time: 4:00 pm EDT (2:00 pm Socorro, 1:00 pm Tucson)
Past minutes, etc on MMA Imaging and Calibration Division Page
Agenda
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It was time for monthly reports, now become bimonthly reports. The July/August 2001 NSF Bi-Monthly Report is available at Carolyn's Place.
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Stephane's group has performed some simulations on a file provided by Crutcher:
"We made a few test with Dick Crutcher polarisation images. Results
can be downloaded at here.
They are astonishing: ALMA+SD completely fails. The "hybrid" technique
does a decent job without errors, but has more limited success in the "typical"
error case produced. Errors are dominated by the pointing error in this
case (just by accident, we don't control the random numbers)."
Some comments from AW are on
the science summary page (see above).
Mark has put his surface error simulations on a
WWW
site.
These simulations, including pointing errors, surface errors and aperture
illumination offset with an MEM image reconstruction technique, basically
verified results from IRAM incorporating pointing errors and a CLEAN-based
image reconstruction. Some of the improvement in image quality found by
including the ACA data could also be achieved by inclusion of the SMA instead.
He found that the expected frequency dependence was much less steep than
expected. Experiment showed that this was probaby traced to inclusion
of the aperture illumination offsets. Emerson suggested that the
latter could be dealt with as simply as treating it as a (u,v,w) offset.
If this does not turn out to be accurate, Holdaway suggests software correction,
time consuming, or tightening of antenna specifications.
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Travel
Oh, always
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