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Region selection in cgdisp

PostPosted: Wed Jun 19, 2019 5:38 pm
by bnorfolk
Hi again,

Quick question, more of a confirmation. I'm zooming in to my region of interest in cgdisp using the box method, I'm looking at a protoplanetary disk so it's very small. The region documentation on miriad says for the arcsec option "the coordinates are in arcseconds, relative to the reference pixel". Does this mean that my region (where the size is defined by my box input) will be centred on the reference pixel, where this reference pixel is (in RA and DEC) what I pointed the telescope at during the observations?

Cheers,

Re: Region selection in cgdisp

PostPosted: Fri Jun 21, 2019 10:08 am
by ste616
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 centre in each of the RA and Dec directions.

Re: Region selection in cgdisp

PostPosted: Fri Jun 21, 2019 10:50 am
by bnorfolk
Makes sense, thanks

And the centre of field is the RA and DEC the telescope was pointed at?

Re: Region selection in cgdisp

PostPosted: Fri Jun 21, 2019 11:51 am
by ste616
Yes.