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.

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