This seems to have worked perfectly -- thanks very much!
Sarah
David Berry wrote:
> Hi Sarah,
> Just to expand on Tim's point, the way to do this is
> as follows:
>
> % wcsatrrib 13c0.sdf set alignsystem vrad
> % wcsatrrib 12c0.sdf set alignsystem vrad
> % wcsalign 13c0 12co
>
> Note, the 13co and 12co cubes will then continue to align using radio
> velocity in all subsequent operations until you change the alignsystem
> attributes again.
>
> David
>
> On 22 October 2010 14:36, Horst Meyerdierks (ROE) <[log in to unmask]> wrote:
>
>> Hi Sarah,
>>
>> Specdre's RESAMPLE (which is now Figaro's RESAMP) was
>> written to do this. It essentially resmaples all rows
>> (spectra) of a cube to a specified new linear grid.
>> RESAMP both cubes to the same v grid (and same v range)
>> and they should become easier to intercompare.
>>
>> However, Specdre predates WCS and was then subsumed in
>> the broom cupboard that is called Figaro, i.e. no features
>> like WCS were added. So it may not cope with how your
>> cube describes the velocity information.
>>
>> Still, there may be a tool to change the v info from a
>> WCS form to an appropriate old-fashioned form. I haven't
>> done much WCS, and no spectroscopy for many years, so
>> don't know about that.
>>
>> Cheers,
>> Horst
>>
>> On Fri, Oct 22, 2010 at 12:28:51PM +0100, S F Graves wrote:
>>
>>> Hi,
>>>
>>> I want to try and align a 13CO cube and 12CO cube in velocity space, so
>>> that I can look at optical depth effects in the line wing.
>>>
>>> I tried simply using WCSALIGN, but this seems to produce a completely
>>> blank output cube.
>>>
>>> If I use SQORST to rebin my 13CO cube spectral axis to the same channel
>>> width as the 12CO cube (1kms), then I have the problem that the channel
>>> bins don't have the same start and end points -- i.e. the 13CO channel
>>> goes from 5.39 to 4.39, whereas the 12CO channel goes from 4.08 to 5.08
>>> (my 13CO cube was previously in 0.1 km/s bins, so from my point of view
>>> sqorst has shifted this cube by roughly three 0.1km/s channels from
>>> where I would like it to be).
>>>
>>> Does anyone know if any of the KAPPA or DATACUBE tools can do this? I
>>> was sure that I'd seen a STARLINK command to do this in the past, but I
>>> don't seem to be able to find one now.
>>> Sarah
>>>
>>> --
>>> Sarah F Graves
>>> Cavendish Astrophysics Group University of Cambridge
>>> Tel: +44 1223 760796
>>>
>>>
>>>
>>>
>> --
>> Horst Meyerdierks Royal Observatory Edinburgh
>> Linux/Network Manager [log in to unmask]
>> http://www.roe.ac.uk/~hme/ +44-131-6688-309
>>
>>
--
Sarah F Graves
Cavendish Astrophysics Group
University of Cambridge
Tel: +44 1223 760796
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