Updated version of charm2.stc

LukeCEL · Post #1by **LukeCEL** » 03.11.2018, 21:26

Hi everyone. The new thread by onetwothree about restarting the development of Celestia re-kindled my interest in updating the star catalogs of Celestia. In particular, one thing that might be easy to do is charm2.stc, which is a catalog of stellar radii using measurements of stellar angular size. Anyway, CHARM2 was published in 2005 and since then, there have been many new catalogs that I could use for the apparent diameters—not to mention Gaia DR2, which provides the distances which are needed to convert the apparent diameter to a real diameter.

On VizieR there's a list of options—just select "Diameters" in the scroll-down menu for Astronomy, then click Find Catalogs for the list. Do you have any suggestions for which one I should use? If not I'll just use CHARM2 and try to update that using Gaia DR2.

SpaceFanatic64 · Post #2by **SpaceFanatic64** » 03.11.2018, 22:51

Luke, it would also be cool if visualbins and spectbins were updated to have your Binary Star Catalog addon.

Post #3by **selden** » 03.11.2018, 22:51

So long as you choose a specific catalog, specify what it is and document all of the changes you make, I think it should be fine.

Ideally, anyone should be able to follow the same procedure you did and get the same results.

LukeCEL · Post #4by **LukeCEL** » 04.11.2018, 12:52

SpaceFanatic64 wrote:Luke, it would also be cool if visualbins and spectbins were updated to have your Binary Star Catalog addon.

I'm actually considering updating visualbins.stc with a data from Cvetković et al. (2010). It's going to take a while, though, since I'd have to extract orbits from the Sixth Orbit Catalogue. If anybody knows of any more data sources that I could use, please send them my way.

selden wrote:So long as you choose a specific catalog, specify what it is and document all of the changes you make, I think it should be fine.

Okay, thank you. My first choice was to use the JMMC Stellar Diameters Catalog v2, which is a massive catalog that my measly computer can't handle. It's going to be harder than I thought...

SpaceFanatic64 · Post #5by **SpaceFanatic64** » 04.11.2018, 18:18

Luke, can you create an STC code that modifies Rigel and Spica as binary stars?

Joey P. · Post #6by **Joey P.** » 04.11.2018, 19:04

Charm2 is wildly inaccurate and obsolete. Definitely needs an update. Thanks.

Askaniy · Post #7by **Askaniy** » 11.11.2018, 11:41

LukeCEL, theoretically, can you create a full star catalog from scratch?

LukeCEL · Post #8by **LukeCEL** » 11.11.2018, 15:43

Askaniy wrote:LukeCEL, theoretically, can you create a full star catalog from scratch?

I don't know how to create a stars.dat file. However, usually what I do to create a star catalog (in .stc) is I download some data from SIMBAD, copy and paste that data into Microsoft Excel, play around with that, copy and paste the new data into a text editor, and use find and replace to replace tabs with line breaks, etc. A full star catalog would be too much data for my computer to handle, but it might be possible to do in chunks.

LukeCEL · Post #9by **LukeCEL** » 23.12.2018, 01:02

Hi everyone. I've created a preliminary version of jsdc.stc, a stellar radius catalog meant to supersede charm2.stc. It contains radii for 66,295 stars.

For these new star catalogs I'm trying to build them using Perl scripts to make my procedure easily reproducible. For more information, see LukeCEL/jsdc on GitHub. I've also re-worked buildstardb.pl to create an updated version of the stars.dat file.

For jsdc.stc, I've used the enormous JMMC Stellar Diameters Catalogue, and cross-matched it with the Hipparcos Catalogue using the CDS X-Match Service. Then I used a Perl script to extract the values, using stars.txt as the source of distances.

Here's the file. Any feedback is appreciated.