Hi Stephanie,
The problem is caused by the fact that your
data uses a CAR projection. The published FITS-WCS standard defines a
CAR projection differently to the way in which the previous ad-hoc
AIPS standard defined it. And there is no sure way for a piece of
software to know which definition is being used since they use the
same keywords and keyword values. The fits2ndf command defaults to the
published FITS-WCS definition, but allows the user to over-ride this
choice. See the help for parameter WCSATTRS:
% conhelp fits2ndf par wcsattrs
You should add ' wcsattrs="carlin=1" ' (without the enclosing single
quotes, but with the double quotes) when running fits2ndf to force it
to use the old AIPS definition of a CAR projection.
David
On 19 July 2012 08:59, Stephanie Haeffner
<[log in to unmask]> wrote:
> Hello,
>
> I try to read in a fits file via the CONVERT package before applying some
> cluster find algorithm.
> I use the command.
> ndf2fits "fitsfile*.fits" "*"
>
> If I open the produced sdf file I get problems with the WCS system. The
> data are in galactic coordinated, but applying the coordinate grid in gaia
> (see the attached screenshot) works just for longitudes between 0 and 180
> degrees.
>
> I tried to use the ENCODINGS command with the ndf2fits command, but for
> each encoding type I just get an error message:
> !! WCS information could not be read using the FITS-IRAF encoding. ! The
> output NDF will still be created but will not contain any WCS information.
>
> The fits header of the fits contains:
> SIMPLE = T / Standard FITS format
> BITPIX = 16 / Bits per pixel
> NAXIS = 3 / Number of axes
> NAXIS1 = 493 / Number pixels on axis 1
> NAXIS2 = 2881 / Number pixels on axis 2
> NAXIS3 = 81 / Number pixels on axis 3
> CTYPE1 = 'VELO-LSR' / axis 1 coord type
> CRVAL1 = -3.198000E+02 / coord value at CRPIX1
> CDELT1 = 1.300000E+00 / linear pixel spacing axis 1
> CRPIX1 = 1.000000 / ref pixel for axis 1
> CTYPE2 = 'GLON-CAR' / axis 2 coord type
> CRVAL2 = 1.800000E+02 / coord value at CRPIX2
> CDELT2 = -1.250000E-01 / linear pixel spacing axis 2
> CRPIX2 = 1.000000 / ref pixel for axis 2
> CTYPE3 = 'GLAT-CAR' / axis 3 coord type
> CRVAL3 = 0.000000E+00 / coord value at CRPIX3
> CDELT3 = 1.250000E-01 / linear pixel spacing axis 3
> CRPIX3 = 41.000000 / ref pixel for axis 3
> BSCALE = 3.364563E-04 / real = int*bscale + bzero
> BZERO = 9.499844E+00 /
> DATAMIN = -1.000000E+00 / minimum real value
> DATAMAX = 2.000000E+01 / maximum real value
> BLANK = -32768 / missing data flag
> BUNIT = 'K' / main beam brightness temp
> COMMENT Spectra linearly interp'ed for <= 2 missing channels
> COMMENT lb image slices interp'ed for single missing pts
> COMMENT ----------------------------------------
> COMMENT | A composite of surveys from |
> COMMENT | Dame, Hartmann, & Thaddeus (2001) |
> COMMENT | ApJ, 547, 792 |
> COMMENT ----------------------------------------
> COMMENT Axis units: v(km/s) x LII(deg) x BII(deg)
> COMMENT Contact: Tom Dame ([log in to unmask])
> COMMENT Created: Thu Jun 24 14:35:13 2010
> END
>
>
> The fits file I use is downloadable here:
> http://www.cfa.harvard.edu/rtdc/CO/download/COGAL_local_interp.fits.gz
>
> I use the newest version of the linux 6- bit starlink software.
>
> Thank you very much in advance.
>
> Best regards,
> Stephanie Häffner
>
>
> --
> Stephanie Haeffner
> Dipl. Phys.
> Erlangen Centre for Astroparticle Physics (ECAP)
> University of Erlangen-Nuremberg, Department of Physics
> Office 322, Erwin-Rommel-Str. 1, D-91058 Erlangen
> Phone: +49 (0)9131-85-27093
> Fax: +49 (0)9131-85-20799
>
>
>
>
> --
> Stephanie Haeffner
> Dipl. Phys.
> Erlangen Centre for Astroparticle Physics (ECAP)
> University of Erlangen-Nuremberg, Department of Physics
> Office 322, Erwin-Rommel-Str. 1, D-91058 Erlangen
> Phone: +49 (0)9131-85-27093
> Fax: +49 (0)9131-85-20799
>
>
> ----
> Starlink User Support list
> For list configuration, including subscribing to and unsubscribing from the list, see
> https://www.jiscmail.ac.uk/cgi-bin/webadmin?A0=STARLINK
----
Starlink User Support list
For list configuration, including subscribing to and unsubscribing from the list, see
https://www.jiscmail.ac.uk/cgi-bin/webadmin?A0=STARLINK
|