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PostPosted: Fri, 18-01-19, 0:22 GMT 
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Hi everyone (but specifically t00fri, who wrote the script):

I'm looking at the file [url="https://github.com/CelestiaProject/Celestia/blob/master/src/tools/galaxies/deepsky.pl"]deepsky.pl[/url], which uses several input sources ("catalogs/ned1d.txt", "catalogs/sbf.txt", etc.) Does anyone know exactly how to obtain/format these files so that the can be used by the script?


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PostPosted: Fri, 18-01-19, 9:04 GMT 
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LukeCEL wrote:
Hi everyone (but specifically t00fri, who wrote the script):

I'm looking at the file [url="https://github.com/CelestiaProject/Celestia/blob/master/src/tools/galaxies/deepsky.pl"]deepsky.pl[/url], which uses several input sources ("catalogs/ned1d.txt", "catalogs/sbf.txt", etc.) Does anyone know exactly how to obtain/format these files so that the can be used by the script?


LukeCEL,

If you are not an expert with "regular expressions" and perl scripting, you will most probably be plagued with lots of tricky mistakes...

Whenever you make any changes, I expect proper credits that must not be decoupled from the perl sources and the galaxies.dsc output file.

The same kind of remarks apply to any changes of my other scripting results about

  • the various kinds of binary star orbits and their orientations in space (visualbins.stc, spectbins.stc).

  • the globular cluster results (globulars.dsc) and

  • the location files avoiding nasty label-overlaps at all Zoom levels.

Large updates of the perl sources, catalogs and the various output files are part of celestia.Sci in my private Github repository and will be made public in due time...
Please, take also into account that I am an official co-author of Celestia since 2002 (see AUTHORS file).

Fridger (aka t00fri)

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PostPosted: Fri, 18-01-19, 20:26 GMT 
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Here is a celestia.Sci screenshot of the "Exclamation Point Galaxy".

[Click on image by all means for a bigger size. ]
Attachment:
Screenshot_20190118_223009.png
Screenshot_20190118_223009.png [ 404 KiB | Viewed 1471 times ]


Data from NED catalog.

Fridger

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PostPosted: Fri, 18-01-19, 21:35 GMT 
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t00fri wrote:
Large updates of the perl sources, catalogs and the various output files are part of celestia.Sci in my private Github repository and will be made public in due time...
Please, take also into account that I am an official co-author of Celestia since 2002 (see AUTHORS file).

Fridger (aka t00fri)


Fair enough. I just hate to see stuff that's out of date ;) By the way, can you give us an update on how the development?

Also, I quite like the screenshot of Arp 302 / "Exclamation Point Galaxy"! Since it wasn't part of the original galaxies.dsc, does that mean that the new galaxies database will have more galaxies, maybe from the UGC?


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PostPosted: Fri, 18-01-19, 22:08 GMT 
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Quote:
Fair enough. I just hate to see stuff that's out of date ;) By the way, can you give us an update on how the development?

If you take into account the inherent measuring uncertainties, the "out of date effect " is rather modest. The crucial challenges remain to be reliable values for the galaxy distances which often can hardly be improved...

My updates, notably for galaxies and globulars, are essentially finished. For these DSOs the progress came mainly from writing a lot of completely new shader code that also provides almost realistic coloration for a given instrumental color profile and given B-V indices.
And YES more galaxies are included from various (minor) catalog updates. And YES my perl scripts have become even more complex... :°

Here is the coloration due to an estimate of B-V indices for the Arp 302 pair :
[Click on image for a bigger size by all means]
Attachment:
Screenshot_20190118_224246.png
Screenshot_20190118_224246.png [ 491.1 KiB | Viewed 1469 times ]

This matches the more reliable color photos pretty well (using SDSS color profile).
A longtime problem is still partly unsolved: to infer from existing catalog data whether the spiral arms are turning clockwise or counter-clockwise... :°

Irregular galaxies were rendered via a Diffusion Limited Aggregation algorithm (DLA) which turned out to be a very fruitful approach. You may glance at some example here
viewtopic.php?f=11&t=628

Cheers,
Fridger

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PostPosted: Fri, 18-01-19, 22:42 GMT 
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That pair is visually difficult for my sky; there is another pair very similar but more easy: NGC 5544/5545 (Arp 199) still in Bootes...

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PostPosted: Fri, 18-01-19, 22:52 GMT 
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Yeah Massimo, this is what I get:

[click on image for a bigger size!]
Attachment:
Screenshot_20190118_235032.png
Screenshot_20190118_235032.png [ 382.11 KiB | Viewed 1464 times ]


Cheers

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PostPosted: Fri, 18-01-19, 22:59 GMT 
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Beautiful!

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