On Sun, Jun 17, 2012 at 8:21 PM, Eduardo Unda-Sanzana
<[log in to unmask]> wrote:
> On 17 June 2012 23:11, Tim Jenness <[log in to unmask]> wrote:
>> If you converted from FITS then the epoch header should have been
>> filled in from the DATE-OBS header originally. The DATE-OBS in the
>> FITS header is just a memory of the original FITS header rather than
>> an expression of the WCS. I assume the header in this case did not
>> come from a FITS file.
> Yes it did. The NDF produced from the original FITS file has the right
> DATE-OBS but the EPOCH is missing (I think it was absent from the FITS
> headers). However, when I convert back to FITS this strange DATE-OBS
> is added. I'll try to get one of the original FITS files in case this
> is useful.
Have you sent David Berry a test file? If the input FITS file has a
DATE-OBS then the AST frameset should have an epoch of that value and
converting back to FITS should restore the value. Note that the EPOCH
FITS header is not relevant.
Is it possible that you have an MJD-OBS FITS header which has some
kind of default value that differs from DATE-OBS? I think AST will
take MJD-OBS or MJD-AVG in preference to DATE-OBS.
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