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PostPosted: Wed, 15-04-20, 16:05 GMT 
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Joined: Wed, 05-12-18, 22:11 GMT
Posts: 19
Hi,

I'm working on adding some globular clusters from the Magellanic Cloud. First one I'm doing is Hodge 11.

Code:
Globular "Hodge 11:ESO 57-76:KMHK 1700:LW 437"
{
   RA               6.23970  # [hours]
   Dec            -69.84858  # [degrees]
   Distance       1.631e+05  # [ly]
   Radius                64  # [ly], mu25 Isophote
   CoreRadius         0.250  # [arcmin]
   KingConcentration   1.09  # c = log10(r_t/r_c)
   AbsMag           -6.5649  # [V mags]
   InfoURL  "http://simbad.u-strasbg.fr/sim-id.pl?Ident=Hodge 11"
}

I'm reasonably confident that I have most of the parameters correct. I got the CoreRadius and KingConcentration parameters from Table 3 of Lanzoni et al. (2019).

I am the least confident about my Radius parameter. I got it by using the angular size listed on SIMBAD, but by looking at the references, I couldn't really tell whether it was the mu25 isophote diameter. I heard somewhere that the mu25 isophote is a standard for measuring the diameters of objects, so is it okay to use the diameter listed on SIMBAD?

Thanks in advance,
Luke


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PostPosted: Wed, 15-04-20, 20:09 GMT 
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Joined: Fri, 31-08-07, 7:01 GMT
Posts: 4675
Location: Hamburg, Germany
Hi Luke,

from my original 2008 work on globular clusters for Celestia

[Click on image to make it better readable:]
Attachment:
Screenshot_20200415_214439.png
Screenshot_20200415_214439.png [ 35.68 KiB | Viewed 313 times ]


and now the missing definition
Attachment:
Screenshot_20200415_214524.png
Screenshot_20200415_214524.png [ 49.67 KiB | Viewed 313 times ]


Cheers
Fridger

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PostPosted: Thu, 16-04-20, 22:47 GMT 
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Joined: Wed, 05-12-18, 22:11 GMT
Posts: 19
Hi, thanks for the response,

I did come across those two posts of yours ;) Unfortunately, the image comparison of M4 with the moon is now gone. But that's fine, I just did a comparison of my own using Celestia:

Attachment:
M4-moon-comparison.png
M4-moon-comparison.png [ 429.93 KiB | Viewed 295 times ]


Unfortunately, my confusion about the mu25 isophote remains; specifically, where to find it. In the literature, I've found apparent diameters for star clusters, but rarely do they explicitly say whether it's the mu25 isophote or some other isophote. What do I do in that scenario?


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