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
|