<div dir="ltr"><div><div>Hi Cormac,<br><br></div>Please see attached the vex. I am interested in EF-YS-NK-HH-O8. <br><br></div><div>cheers,<br></div>Sam</div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, May 15, 2017 at 7:45 AM, Cormac Reynolds <span dir="ltr"><<a href="mailto:cormac.reynolds@csiro.au" target="_blank">cormac.reynolds@csiro.au</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">hi Sam,<br>
<br>
just following up on Adam's point. The most common cause of a very high residual fringe rate (as yours appears to be) in an otherwise functioning array is an error in the station position(s). If you send the vex file you used, and the stations you are interested in, it should be straightforward to say if that is a likely cause or not.<br>
<br>
cheers,<br>
Cormac.<span class=""><br>
<br>
On 13/05/17 19:57, Hagatiana Andrianomena wrote:<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
Hi Adam,<br>
<br>
Many thanks for your explanations.<br>
<br>
Cheers,<br>
Sam<br>
<br>
On Sat, May 13, 2017 at 1:37 PM, Adam Deller <<a href="mailto:adeller@astro.swin.edu.au" target="_blank">adeller@astro.swin.edu.au</a><br></span><span class="">
<mailto:<a href="mailto:adeller@astro.swin.edu.au" target="_blank">adeller@astro.swin.edu<wbr>.au</a>>> wrote:<br>
<br>
Hi Sam,<br>
<br>
Integration time will affect the maximum fringe rate you are<br>
sensitive to. Shorter integrations = higher fringe rate before you<br>
lose signal due to decorrelation. But normally this is not a<br>
limitation. I would be fairly surprised if a 1 second integration<br>
time was a problem (unless there is an issue with the observing setup).<br>
<br>
Spectral resolution will affect the maximum residual delay you are<br>
sensitive too. Finer spectral resolution = larger delay before you<br>
lose signal due to decorrelation.<br>
<br>
These are not DiFX-specific things, but general to radio<br>
interferometers / correlators. To know what values are reasonable,<br>
you need to know your instrument and what the expected residual<br>
fringe rate and delay are.<br>
<br>
Cheers,<br>
Adam<br>
<br>
On 12 May 2017 at 23:59, Hagatiana Andrianomena<br></span><span class="">
<<a href="mailto:handrianomena@ska.ac.za" target="_blank">handrianomena@ska.ac.za</a> <mailto:<a href="mailto:handrianomena@ska.ac.za" target="_blank">handrianomena@ska.ac.z<wbr>a</a>>> wrote:<br>
<br>
Hi DiFX users,<br>
<br>
I got a question regarding the integration time in the setup:<br>
SETUP default<br>
{<br>
tInt = 1.000000<br>
fftSpecRes = 0.12500000<br>
specRes = 0.12500000<br>
doPolar = True<br>
maxNSBetweenACAvg = 2000000<br>
}<br>
<br>
I got this default setup by running oms2v2d using the .oms file<br>
from the experiment. When running the difx I got no fringe but<br>
from changing the tInt to<br>
0.08 and both fftSpecRes and specRes the result seems to suggest<br>
I got fringe (see plot attached).<br>
<br>
I am not quite sure whether it is a naive question but I wonder<br>
if there is a simple rule of thumb to get the right values of<br>
those parameters in order to get fringe. I do not have much<br>
experience with DiFX I must say though.<br>
<br>
Regards,<br>
Sam<br>
<br>
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Dr. Adam Deller<br>
ARC Future Fellow, Senior Lecturer<br>
Centre for Astrophysics & Supercomputing<br>
Swinburne University of Technology<br>
John St, Hawthorn VIC 3122 Australia<br></span>
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