[daip] Project BS077 (Sept.30,1999)
Leonia Kogan
lkogan at aoc.nrao.edu
Wed Jun 27 12:20:09 EDT 2001
Peter,
I hope your project is VLBA project.
You can look at the behavior of Pulse Cal for each antennas under
/home/aspen6/astronomy.
I do not know when your project was observed.
So I give you example of the project bs090a observed at april of 2001.
The file /home/aspen6/astronomy/apr01/bs090a/bs090atsm.BR.ps.gz should include
the plots of phase of the pulse cal for each antenna as a function of time.
These plots are very smooth usually. So if PCCOR finds solution for one time interval it will work for the whole experiment.
Send me please the PCCOR's and the following CLCAL's input parameters you used, and the time when your project was observed.
Leonia
You should received the file of paper
from our (NRAO) analysts. This file includes some pages with the plots of
delay
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>From owner-daip at kochab.cv.nrao.edu Wed Jun 27 09:50 MDT 2001
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Date: Wed, 27 Jun 2001 10:48:29 -0500
From: Peter Kortenkamp <pkortenk at blue.weeg.uiowa.edu>
To: daip at cv3.cv.nrao.edu
X-EXP32-SerialNo: 00002843
Subject: [daip] Project BS077 (Sept.30,1999)
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To: Contact person Geoff Bower
I'm a graduate student at the University of Iowa working with Steve Spangler
(steven-spangler at uiowa.edu). I am in the process of reducing the data from
BS077 and am currently trying to correct for instrumental phase. I've tried
using PCCOR but the results show the phase vs frequency plots having sharp
jumps between channels for many baselines. As a result I moved on to manual
phase correction (9.4.8.5 in "Cookbook"). Now when I run POSSM on a section
of scan from which the fringe fitting sample was taken everything is nice and
flat and continuous. However when I run POSSM on a different scan of the same
calibrator (and of course from the same frequency band) I discontinuous jumps
between channels again. In fact the CL table seems to work only for the scan
from which the fringe fitting sample was taken. Does this mean the assumption
of constant instrumental offsets does not hold in this case? It seems strange
that instrumentally induced phases would change from one hour to the next.
Here are a few things I've tried with no success:
-different ref. ant.
-different scan for fringe fitting
-longer solution intervals
Do I need to create a different CL table for each scan? I should say this is
my first experience with AIPS and have been at it for only about a month. No
doubt it is something simple but any help at all would be appreciated.
Thanks for your time,
Peter Kortenkamp
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