standard task: ERROR: Cannot convert between selected units

Nicola Caon wrote on Oct 05, 2007

Hi,
we are trying to create the sensitivity function using the Iraf task "standard" in noao.imred.specred.

However, we get the error:
ERROR: Cannot convert between selected units

The spectrum seems to be correctly calibrated in wavelength (nanometers units) as seen with splot.

There is probably something wrong in the fits spectrum header, or in the standard star data table, however we seem to be unable to find it.

The command we are executing is:

standard starrbnspec_azul.tot starrbnspec_azul.txt star_name="cd32d9927" caldir = "./" extinct="./paranalextinc_n.dat" airmass=1.012 exptime=120.0

We are running Iraf 2.12.2a in a RHEL4 box.

We have put a tar archive with the relevant files in ftp://ftp.iac.es/out/ncaon/standard.tar.gz

Thanks very much for your help
Nicola

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Nicola Caon wrote on Oct 05, 2007

The problem was due to the DC-FLAG keyword missing from the spectrum fits header. We add it manually with value 0 and the task "standard" now works fine.

These files were produced by the FLAMES ESO pipeline, which apparently does not add the DC-FLAG keyword when doing the wavelength calibration.

Cheers
Nicola

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Last post on Oct 05, 2007