<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><font size="2"><span style="font-size:10pt;">Thanks Petr,<br>
<br>
Unforunately phot.count does not seem correct...<br>
phot.count represents the number of photons counted<br>
by the instrument, while what I'm talking about is<br>
really instrumental data numbers (ADUs) which are far<br>
from being the number of photons.<br>
<br>
That is, I cannot take the number of ADUs, multiply<br>
it by the energy of a photon (which I can derive from the wavelength info<br>
of obscore) to get a representative flux...<br>
<br>
That is why I would like to have a phot.uncalibrated,<br>
or phot.adu, or similar... any other idea?<br>
<br>
Thanks,<br>
Alberto</span></font><div><span class="Apple-style-span" style="font-size: 13px;"><br></span><div><div>On 24 Jul 2015, at 16:17, Petr Skoda wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>On Wed, 22 Jul 2015, Alberto Micol wrote:<br><blockquote type="cite"><br></blockquote><blockquote type="cite">Dear ObsCorers,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">At ESO we are serving spectra very well calibrated in wavelength, but uncalibrated in flux.<br></blockquote><blockquote type="cite">What would be the correct o_ucd value for such data?<br></blockquote><blockquote type="cite">I cannot find a UCD that could fit… something like: phot.uncalibrated would be nice to have…<br></blockquote><blockquote type="cite">Any idea?<br></blockquote><br>Hi Alberto,<br><br>In stellar astronomy we formally describe the vertical axis as integrated flux in ADU or counts ....<br>It is in principle produced by summing all pixels values in given wavelength but modified by various sensitivies of detetror (flat-field etc) . So perhaps something like flux in counts may be used??<br>So UCD="phot.count"<br>?????<br><br><br>Than the problem comes with continuum normalization made by some pipelines. For this was already a suggestion by Mirellei for SDM<br><br>Char.FluxAxis.CalibrationStatus='NORMALIZED'<br>Char.FluxAxis.unit=NULL or 'unitless'<br>Char.FluxAxis.ucd=phot.flux;arith.ratio;<br><br><br>Is there any other suggestion ?<br><br>Just my practical view for intended usage of obscore: I am either interested in getting SOME form of spectra of my object - so I am perfectly happy with the RAW extracted spectrum - in counts (or ADUs) or in a SPECIFIC form for analysis - than I prefer the FLUXCALIB=normalized or ABSOLUTE - if I already know about many spectra of the same object in given form. But more flexible approarch is to use DataLink.<br><br><br>OTOH - it is not sometimes obvious the spectra are normalized to continum without visual inspection - you see the most values are at level 1.0 and there is not visible skew of the spectra ....<br><br>BTW - I am glad that the ESO is still considering the VO as a viable technology for presenting data ....<br><br>*************************************************************************<br>* Petr Skoda Phone : +420-323-649201, ext. 361 *<br>* Stellar Department +420-323-620361 *<br>* Astronomical Institute AS CR Fax : +420-323-620250 *<br>* 251 65 Ondrejov e-mail: <a href="mailto:skoda@sunstel.asu.cas.cz">skoda@sunstel.asu.cas.cz</a> *<br>* Czech Republic *<br>*************************************************************************</div></blockquote></div><br></div></body></html>