[mmaimcal] Meeting

[Al Wootten]

Ho, ho ho MMAImCal Merry Christmas!

For your MMA holiday bonus, no meeting on 28 Dec or the following Monday.
I'll see many of you at URSI or the AAS meeting I guess.  We'll resume
on 11 Jan.  Until then, perhaps I'll share a question I've been considering
for your holiday amusement.

1/f noise again.  Let's do a continuum thought experiment.  Let's say
we are imaging a patch of sky larger than the beam at 7 or 3mm.
Since our bandwidth is so large relative to the observing frequency,
in the interferometric mode we decide to use multiple frequency channels,
as we don't want bandwidth smearing or other nasty effects in the data.
Then I image the same patch of sky in total power mode.  Do I decide
to do this again by using multiple frequency channels?  If so, it seems
to me that in the limit of lots of narrow frequency channels, the 1/f
noise diminishes in importance.  When I mosaic, I would presume I would
do this channel by channel, then sum the channels for the final continuum
map?  Or not?  This seems to me to be the corollary to the way we make
spectral line maps, by making as many as possible as fast as possible, then
adding them up later, to try to get around atmospheric systematics.

Clear skies,
Al
+--------------------------------------------------------+
| Alwyn  Wootten   (http://www.cv.nrao.edu/~awootten/)	 |
| Project Scientist, The Millimeter Array                |
| Astronomer, National Radio Astronomy Observatory       |        
| 520 Edgemont Road, Charlottesville, VA 22903-2475, USA |
| (804)-296-0329 voice Help us build The Millimeter Array|
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