2009/1/16 Jane Buckle <[log in to unmask]>:
> Hi David,
>
> Its probably worth checking with Brad whether this data was taken during the
> RTS timing problems, which I think occured on 20081007 - in which case there
> may be deeper problems than oracdr can solve.
Hi Jane,
Thanks for the suggestion. But what ever else is wrong with the data,
I think there is also something wrong with the autogrid algorithm. If
you use the OUTCAT parameter of MAKECUBE to list the detector sample
positions, and then use TOPCAT to display them graphically, you can
see they form a regular pattern that autogrid should be able to
handle.
David
>
> Cheers,
>
> Jane
>
> David Berry wrote:
>>
>> 2009/1/15 Tim Jenness <[log in to unmask]>:
>>
>>>
>>> I've had a closed look at #54 on 20081007 that has the different base
>>> position. The others are all in the same group with a current version
>>> of oracdr. This seems to be an issue with the position used as the
>>> frequency reference. The base position reported in the state structure
>>> is correct, as you can see from using makecube:
>>> makecube
>>>
>>> /Volumes/jcmtdata/raw/acsis/spectra/20081007/00048/a20081007_00048_01_0001.sdf
>>> autogrid
>>> Projection parameters used:
>>> CRPIX1 = 2
>>> CRPIX2 = 225.797959178686
>>> CRVAL1 = 85.4158333333333 ( RA = 5:41:39.8 )
>>> CRVAL2 = -1.9075 ( Dec = -1:54:27 )
>>> CDELT1 = -0.254 ( -914.4 arcsec )
>>> CDELT2 = 0.00102777777777778 ( 3.7 arcsec )
>>> CROTA2 = 33.2999992370605
>>> (noting that autogrid is having serious trouble with the RA pixel size).
>>>
>>
>> I've spent a lot of today looking into this autogrid failure. It
>> always was a very complex and fragile algorithm, and this particular
>> data set throws it badly out for some reason which I don't understand
>> yet. I could press on with this investigation for another day or so to
>> try and track down the issue, but it means more time off STC, which
>> has already suffered badly recently due to a spat of bug reports.
>>
>> David
>>
>
> --
>
> Dr Jane V. Buckle
> Astrophysics Group, Cavendish Lab, J J Thomson Avenue, Cambridge CB3 0HE
> Tel: +44 (0)1223 337298
>
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