Search found 79 matches
- Fri Feb 15, 2013 10:45 am
- Forum: Calibration
- Topic: Bad feed? To flag or not to flag - that is my question.
- Replies: 4
- Views: 19854
Bad feed? To flag or not to flag - that is my question.
I've been looking at calibrating some observations from mid-2011, and the first thing that I did was to split out the 1934 observation and plot the XX and YY product amplitudes as a function of time. It was immediately obvious that there is significantly more scatter in the ant 3 baselines for the Y...
- Tue Feb 12, 2013 12:51 pm
- Forum: MIRIAD
- Topic: Matching resolution in CABB
- Replies: 3
- Views: 5578
Re: Matching resolution in CABB
Hi Mark - just a quick question about using the fwhm parameter in INVERT which follows on from Sara's post and your reply. From the documentation it seems a little unclear what specifying a value for fwhm actually does. The help file says: "It specifies the FWHM of an image-domain gaussian -- t...
- Fri Feb 01, 2013 9:11 am
- Forum: Calibration
- Topic: Oscillations in 1934 spectrum after bandpass cal
- Replies: 12
- Views: 57026
Re: Oscillations in 1934 spectrum after bandpass cal
I already said it in an email, but I thought I'd acknowledge it here too - great stuff Emil! Thanks for taking the time to look into this for me! For the moment it is just good to have an idea what is going on, and that it is to some extent unavoidable using the simplest approach to getting a bandpa...
- Fri Feb 01, 2013 9:06 am
- Forum: MIRIAD
- Topic: How does nfbin divide the CABB band?
- Replies: 2
- Views: 4969
Re: How does nfbin divide the CABB band?
Great - thanks a lot Mark!
- Thu Jan 31, 2013 5:08 pm
- Forum: MIRIAD
- Topic: How does nfbin divide the CABB band?
- Replies: 2
- Views: 4969
How does nfbin divide the CABB band?
Hi guys, Quick question about the nfbin parameter: how exactly does the 2100MHz CABB band get divided when using nfbin? Say I set nfbin = 16. Does this mean that the band will be divided up into 16 bins, with 2100MHz (being the middle of the band) sitting precisely on the dividing line between the 8...
- Tue Jan 29, 2013 1:47 pm
- Forum: Calibration
- Topic: Oscillations in 1934 spectrum after bandpass cal
- Replies: 12
- Views: 57026
Re: Oscillations in 1934 spectrum after bandpass cal
Thanks very much for your reply Mark. A couple of people I have talked to since posting this have raised the possibility of additional sources in the field being the cause. For example, Emil Lenc said that he did some high dynamic range imaging of the 1934 region a few years back and found some exte...
- Thu Jan 24, 2013 11:34 am
- Forum: Calibration
- Topic: GPBOOT Multiplying by NaN
- Replies: 3
- Views: 12809
Re: GPBOOT Multiplying by NaN
Hi Rowan - Craig Anderson here. Just thought I'd give you my two cents because I have been working with 16cm data, calibrating it in much the same way. I have found that the issue you mention occurs whenever GPCAL does not converge on a calibration solution within about 5 iterations or so for the su...
- Wed Jan 23, 2013 11:04 am
- Forum: MIRIAD
- Topic: Issue with 'Divide & Conquer', then UVCAT
- Replies: 5
- Views: 8138
Re: Issue with 'Divide & Conquer', then UVCAT
Thanks for the help Jamie, and thanks for looking into the 'wobbles' issue for me! I owe you multiple beers next time I'm up...
- Tue Jan 22, 2013 12:43 pm
- Forum: MIRIAD
- Topic: Issue with 'Divide & Conquer', then UVCAT
- Replies: 5
- Views: 8138
Re: Issue with 'Divide & Conquer', then UVCAT
Also - I want to combine UV data from two different epochs (that has been separately calibrated) for imaging. UVCAT is the correct task for this purpose, is it not?
- Tue Jan 22, 2013 11:53 am
- Forum: MIRIAD
- Topic: Issue with 'Divide & Conquer', then UVCAT
- Replies: 5
- Views: 8138
Re: Issue with 'Divide & Conquer', then UVCAT
Thanks Jamie - much appreciated. You said that "In terms of calibration, I have not personally seen a single instance where calibration of individual chunks has been more effective than calibration of the entire bandwidth at once". Just to clarify - you mean that you've never seen an insta...