Obtain spectral lines from NED query · Issue #3446 · astropy/astroquery · GitHub
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Obtain spectral lines from NED query #3446

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@cosimoNigro

Hello,

it seems that it is not possible to obtain the spectral lines from a NED query.

(I am referring to these in the NED search, for clarity)
Image

It seems that the photometry table is available via the get_table method, but this - as the name suggests - incudes only photometric measurements.
On the other hand, one can fetch the spectra with get_spectra.
But I'd like to access directly the line information.
Any workaround?

Best, and thank you!

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  1. cosimoNigro commented on Oct 23, 2025

    @cosimoNigro
    Author

    My bad, apologies, the lines measurement are indeed in the photometry table

    tab = Ned.get_table("NGC1275", table="photometry")
    mask = tab["Observed Passband"] == "[O III] 5007"
    tab[mask]
    <Table length=1>
     No.  Observed Passband Photometry Measurement Uncertainty   Units    ... Coordinates Targeted     Spatial Mode                 Qualifiers                      Comments        
                                                                          ...                                                                                                       
    int32       object             float64            object     object   ...        object               object                      object                         object         
    ----- ----------------- ---------------------- ----------- ---------- ... -------------------- ------------------- ----------------------------------- -------------------------
      119      [O III] 5007              4.545e-13  +/-3.8E-15 erg/cm^2/s ...                      From fitting to map Spectral fittting flag=2; see paper From reprocessed raw data

    Isn't this a bit (semantically) confusing?
    Maybe I am wrong, but I understood "photometry" as a flux measurement in a finite band, as opposed to "spectroscopy" that measure lines through a spectrometer (I'm thinking to photometric vs spectroscopic surveys).
    And indeed the tables are separated in NED.

    If you deem the separation not relevant, I can close the issue.

    P.S. would it be useful to add to the docs a few lines with examples of fetching fluxes or lines measurements?

    Thanks again.

  2. keflavich commented on Oct 23, 2025

    @keflavich
    Contributor

    @cosimoNigro Thanks for pointing this out. If they are separated on the NED page, I'd say it does make sense to separate them in astroquery. A documentation or feature contribution would be welcome, though I defer to @bsipocz for thoughts on whether this is implementable.

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