LineTAP

[Arnold Rots]

FWIW, a good principle for IVOA is to make specifications as general as
possible for application across all subcommunities.
If we are talking about the spectral coordinate axis, frequency and energy
make much more sense than wavelength.
Wavelength, for most of us, just runs the wrong way.
For energy one could use the eV as the basic unit, but using Hz for
frequency probably makes more sense.
That should feel natural for radio and HEA and indeed the physical quantity
of the spectral axis increases as the numbers get bigger.
Powers of 10 can easily be avoided by using the usual prefixes.

Cheers,

Arnold H Rots

Research Associate

SAO/HEAD

Center for Astrophysics | Harvard & Smithsonian

Email: arots at cfa.harvard.edu

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On Fri, Apr 29, 2022 at 7:39 AM Pinheiro de Castro Neves, Margarida <
mcneves at ari.uni-heidelberg.de> wrote:

>
> Hi,
>
> >> Hello,
> >>
> >> Following Margarida nice presentation about LineTAP, here are some
> comments and questions.
> >>
> >> 1 - Choice of units for energy levels
> >> I saw that Joule was proposed. Joule is a bit a strange unit for energy
> levels because 1 Joule is lot of energy whereas rotational levels or
> hyperfine structures contains very few energy. Using Joule means that we
> will have to manipulate quantities as 10E-XX where XX is a lot.
>
> in my former answer I mistakenly read the comment about a proposal for
> joule for wavelength, and you’re talking about energy levels. Sorry,
> please do not consider this part of my answer. I need to get more sleep :)
>
>
> Margarida
>
> —
>
> Margarida Castro Neves
>
> German Astrophysical Virtual Observatory (GAVO)
> Astronomisches Rechen-Institut (ARI)
> Zentrum für Astronomie, Universität Heidelberg  (ZAH)
> Mönchhofstr. 12 - 14, 69120 Heidelberg
> phone +49-6221-54-1891   fax +49-6221-54-1888
> mcneves at ari.uni-heidelberg.de
> http://www.ari.uni-heidelberg.de
>
>
>
>
>
>
>
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