The ATCA Forum

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...

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 ...

Hi Brodie,

No, you must recompile Miriad to change the buffer limit.

Have you tried uvsfit instead of uvfit?

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...

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...

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.

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.

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...

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...

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 ...