Increase the size of galactic and star bases

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LukeCEL
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Post #21by LukeCEL » 26.03.2019, 06:24

The main source, Steinicke's NGC/IC catalog, is probably fine. However, I'm having trouble tracking down the supplementary sources. There might also be newer sources for nearby galaxies.

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Art Blos M
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Post #22by Art Blos » 26.03.2019, 06:40

LukeCEL wrote:The main source, Steinicke's NGC/IC catalog, is probably fine. However, I'm having trouble tracking down the supplementary sources. There might also be newer sources for nearby galaxies.
I am very worried about how the tool calculates the orientation of the galaxy relative to the Earth. Or was the necessary information in the source?
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LukeCEL
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Post #23by LukeCEL » 27.03.2019, 20:01

Art Blos wrote:I am very worried about how the tool calculates the orientation of the galaxy relative to the Earth. Or was the necessary information in the source?

The tool takes the inclination and position angle of the galaxy. Those two are enough to position the plane of the galaxy, but you need a third parameter so the individual arms are in the right position. I don't think there is a standardized way to note this.

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Art Blos M
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Post #24by Art Blos » 28.03.2019, 07:32

LukeCEL < I discovered the current location of the base from which our 10 thousand galaxies were taken. The old address is unavailable since 2007. May be helpful.
https://ngcicproject.org/
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LukeCEL
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Post #25by LukeCEL » 28.03.2019, 21:17

Not sure if this is the right link, I found http://www.klima-luft.de/steinicke/ngcic/ngcic_e.htm which has a download link for an XLS file. But I'll still look for more sources, especially related to distances and other properties.

Also, a bit off-topic, but a bunch of my add-ons finally got updated at the Motherlode! (See this page)

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Art Blos M
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Post #26by Art Blos » 29.03.2019, 05:18

LukeCEL wrote:Not sure if this is the right link
This is the same site that was listed in the original file with the galaxies. The old one is accessible only from the web archive, and by the name of the project I managed to find out where it moved. The appearance of the main page has not changed since.
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norinonoroi
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Post #27by norinonoroi » 07.06.2020, 01:12

I'm new here (just made an account), but I have experience working with the Gaia DR1 and DR2 data releases. What kind of information do you need to include a star? Right Ascension, Declination, distance (from parallax), magnitude, etc? And what kind of limits would you think are reasonable for including a star? distance, magnitude, absolute magnitude? Gaia DR2 has 1.1 billion stars with distances that can be calculated (though large error bounds), I doubt you want them all.

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Post #28by SevenSpheres » 07.06.2020, 02:11

norinonoroi wrote:What kind of information do you need to include a star? Right Ascension, Declination, distance (from parallax), magnitude, etc?

Yes, those and spectral type. The issue though isn't getting the data into a file, but that Celestia only supports HIP and TYC catalog numbers and has issues with loading very large star databases. One of the developers, pirogronian, has been doing some work toward supporting more and larger star catalogs in Celestia (relevant thread); if you know C++ programming we'd be glad to have you help!
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Post #29by Joey P. » 07.06.2020, 02:48

If you aren't aware, we've got a new largest star now, Stephenson 2-18 with a diameter of over 3 billion kilometers. You might want to consider adding it to databases that don't include it yet.
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