The ATCA Forum

Hi all,

I'm experimenting with uvamp and want to centre my source for the task. From previous questions I've asked I know I have to correct for the primary beam attenuation and then measure the source offset with impos. However, I think I may be missing some key inputs. I'm currently following (my input is the result from my imaging process which involves invert,clean,r and restor, the input file for linmos is source.freq.image from restor)

linmos
in=source.freq.image
out=source.freq.correction
rms=(either theoretical rms from invert of the rms read by histo on the dirty map)
bw=bandwidth of the cabb?
cutoff=(no input)
options=(no input)

impos
in=source.freq.correction
coord=(unsure)
type="abspix"
stype=(unset)
options=(unset)

The main issue I have is I'm not sure what my absolute pixel position is and even how to determine it?

Thanks,
Brodie

Hi Brodie,

what are you using to look at your images?
Most image display programs (e.g., kvis, ds9) will show the pixel and world coordinate values of the cursor, so you can just point at your source and read off the pixel offsets. If you need to translate from pixel to world coordinates you can use impos.

There is also the cgcurs task which lets you draw a region around your source. If you look at the file it creates it will have offsets in arcseconds in it. So plenty of choices, pick whatever is handiest for your case.

Cheers,

Mark

Thanks for the help ,cgcurs is what I was looking for