Search found 215 matches
- Fri Jun 21, 2019 10:08 am
- Forum: Imaging
- Topic: Region selection in cgdisp
- Replies: 3
- Views: 7690
Re: Region selection in cgdisp
Hi Brodie, No, it just means you specify offsets with regards to the reference pixel. So, region=arcsec,box(-10,-10,10,10) will be a box 20 arcseconds on a side, centred on the centre of your field. But region=arcsec,box(10,10,30,30) will be the same box centred 20 arcseconds away from the field cen...
- Wed May 29, 2019 12:16 pm
- Forum: Imaging
- Topic: Offset Problem
- Replies: 3
- Views: 6953
Re: Offset Problem
Hi Brodie, I'm unsure on what you're after here. Are you trying to measure the flux density of your source, which is offset, or are you trying to make an image with the source at the centre? If the latter, I wouldn't bother; there really should be no need to do that. But if you really do want to do ...
- Tue May 28, 2019 9:50 am
- Forum: MIRIAD
- Topic: buffer overflow in uvfit
- Replies: 3
- Views: 7476
Re: buffer overflow in uvfit
Hi Brodie,
No, you must recompile Miriad to change the buffer limit.
Have you tried uvsfit instead of uvfit?
No, you must recompile Miriad to change the buffer limit.
Have you tried uvsfit instead of uvfit?
- Mon May 20, 2019 4:44 pm
- Forum: Calibration
- Topic: 7mm Calibration Question
- Replies: 2
- Views: 6800
Re: 7mm Calibration Question
Hi Brodie, Thanks for your question. In general 7mm data doesn't really need the type of automatic flagging provided by pgflag; that's more for bands where there is a lot of RFI. Still, automatic flagging shouldn't hurt either, and it really is up to you to decide whether you include it or not, base...
- Mon Dec 10, 2018 4:01 pm
- Forum: Calibration
- Topic: Different spectral index on bandpass calibrator in 3mm band
- Replies: 10
- Views: 17941
Re: Different spectral index on bandpass calibrator in 3mm b
Hi Jimmy, I think I've had a bit of success in calibrating this data, but it does require using the technique I describe in the calibrator database documentation. The concept is that you first calibrate without consideration of the spectral index, so making the assumption that the average flux densi...
- Wed Dec 05, 2018 9:54 am
- Forum: Calibration
- Topic: Different spectral index on bandpass calibrator in 3mm band
- Replies: 10
- Views: 17941
Re: Different spectral index on bandpass calibrator in 3mm b
Hi Jimmy,
Thanks for that, that all looks pretty good. I have access to all data, whether restricted or not, so I'll go have a look.
Thanks for that, that all looks pretty good. I have access to all data, whether restricted or not, so I'll go have a look.
- Mon Dec 03, 2018 9:33 pm
- Forum: Calibration
- Topic: Different spectral index on bandpass calibrator in 3mm band
- Replies: 10
- Views: 17941
Re: Different spectral index on bandpass calibrator in 3mm b
Hi Jimmy,
Getting better!
But to help any further I think I'm going to have to see your entire process from atlod onwards. Perhaps it would be easier also to let me know which raw data files you're using: I can do the reduction the way I normally do and see what happens.
Getting better!
But to help any further I think I'm going to have to see your entire process from atlod onwards. Perhaps it would be easier also to let me know which raw data files you're using: I can do the reduction the way I normally do and see what happens.
- Wed Nov 28, 2018 11:21 am
- Forum: Calibration
- Topic: Different spectral index on bandpass calibrator in 3mm band
- Replies: 10
- Views: 17941
Re: Different spectral index on bandpass calibrator in 3mm b
Hi Jimmy, Have a read of the bandpass and flux calibration section of the calibrator database manual. http://www.narrabri.atnf.csiro.au/calibrators/calibrator_database_documentation.html#measurement-process-bandpass-flux-calibration I think in your case, it is a little surprising that the spectral i...
- Fri Nov 23, 2018 1:49 pm
- Forum: Calibration
- Topic: Different spectral index on bandpass calibrator in 3mm band
- Replies: 10
- Views: 17941
Re: Different spectral index on bandpass calibrator in 3mm b
Hi Jimmy, Thanks for your question. It would be helpful for me to see some plots of your spectral shapes, just to see how much your spectral indices vary. One thing you might want to try is using the select keyword, or clip keyword, in mfboot to remove any long baselines where Mars gets completely r...
- Fri Mar 16, 2018 3:29 pm
- Forum: Calibration
- Topic: atlod options=notsys and calibration
- Replies: 5
- Views: 10435
Re: atlod options=notsys and calibration
Hi Tim, You're right, changing tvchannels affects the Tsys and therefore changes the scaling factors in an unpredictable way. The only way to reverse this is via options=notsys as you say. In most cases, reversing the online application of Tsys won't have much of a deleterious effect, unless you're ...