Question about inclination angle UCD

[Stéphane Erard]

Hello - thinking of it : 
there are very few UCD for rotational quantities. For solar system objects the reference src.orbital may be misleading, and some services use phys.obliquity for the spin direction (angle between the axis and the orbital plane). It may be a better choice also in this case (at least this is not a position angle, indeed).

Cheers
Stéphane

> Le 21 mars 2025 à 18:09, Baptiste Cecconi via semantics <semantics at ivoa.net> a écrit :
> 
> Thanks all for your answers, I started a draft answer in Slack and then I saw this set of emails. 
> 
> In short, yes, src.orbital.inclination is probably the best shot at this point, since it is already used with the same context.
> 
> Cheers
> Baptiste
> 
>> Le 21 mars 2025 à 11:22, Stéphane Erard via semantics <semantics at ivoa.net> a écrit :
>> 
>> Hello
>> 
>> 
>> In the EPN-TAP interface to exoplanet.eu, we're using src.orbital.inclination for this angle.
>> - although intended for inclination of an orbit on the ecliptic (in the Solar System), the UCD refers to a generic orbital inclination and seems acceptable in this context.
>> This UCD is also used in ESAsky, which takes the values from exoplanet.eu <http://exoplanet.eu/>
>> 
>> Hope this helps
>> 
>> Stéphane Erard
>> ____________________________________________
>> LIRA, Observatoire de Paris
>> 5 place Jules Janssen F-92195 Meudon cédex, France
>> tel : 33 1 45 07 78 19       fax : 33 1 45 34 76 83
>> e-mail : stephane.erard at obspm.fr
>> 
>> 
>>> Le 20 mars 2025 à 21:41, Kelle Cruz via semantics <semantics at ivoa.net> a écrit :
>>> 
>>> Hi folks IVOA folks,
>>> 
>>> (I posted this question in Slack but didn't get a response. I found these email addresses on the wiki and am giving them a try. If there's a better place for discussion, please let me know.)
>>> 
>>> What’s the best UCD to use for the inclination angle of a star? That is, the angle of the star’s rotation axis w.r.t. us. Also known as “viewing angle” or the i in vsin(i).  
>>> 
>>> I don’t think it’s src.orbital.inclination.  But pos.posAng feels wrong too.  
>>> 
>>> Thanks for any advice.
>>> 
>>> Kelle
>>> 
>>> --
>>> Kelle Cruz, PhD (she/her, they/them)
>>> Assoc. Professor, Physics and Astronomy, Hunter College
>>> CEO, ScienceBetter Consulting, LLC
>>> CFO, Startorialist, Inc. <http://shop.startorialist.com/>
>>> Editor-in-Chief, AstroBetter Blog and Wiki <http://astrobetter.com/>
>>> Research Associate, American Museum of Natural History
>>> Visiting Scholar, Flatiron Institute
>> 
>> 
>> 
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ivoa.net/pipermail/semantics/attachments/20250321/e81e040b/attachment-0001.htm>