[evlatests] a little more on aliasing

[Gustaaf van Moorsel]

After my last report on aliasing a few days ago it was suggested I
check if the effect stays the same when changing sources.  If the
effect remains the same when changing sources the earlier proposed
method of fitting to a strong continuum source and applying it to
the source under investigation could possibly work.

Attached are plots showing the aliasing signature on EVLA - EVLA
baseline 4 - 18 for both IFs and both Stokes.  This is L-band, C-
configuration, and 0.78 MHz total bandwidth.  The first shows the
effect on a strong continuum source, and the second the effect on
a nearby strong source, 15 degrees away.  Moreover, the scans are
separated in time by 4 hours.  The result is that the aliasing
signatures in the two cases is very similar.

So, in conclusion:

1 - these observations confirm that the aliasing signature does not
     vary dramatically over a timescale of hours
2 - aliasing does not vary dramatically when moving to another source
     of order 15 degrees away

Gustaaf
-------------- next part --------------
A non-text attachment was scrubbed...
Name: S1T1.pdf
Type: application/pdf
Size: 13452 bytes
Desc: not available
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20080326/ab7c0e37/attachment.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: S2T2.pdf
Type: application/pdf
Size: 13425 bytes
Desc: not available
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20080326/ab7c0e37/attachment-0001.pdf>