New comparison addon (work in progress)

[Danny Lorraine II]

i downloaded it and it is nice. thanks
however, why isn't vv cephei b and VY Canis Majoris present ? is it possible to add them ?

[Danny Lorraine II]

also the sizes are way off , especially betelgeuse and antares. i tried modifiying the stc but failed . how to fix this ? thanks .

[selden]

When a star is missing from Celestia, you have to create a STar Catalog file to define it. It's a plain text file which specifies the star's name and characteristics. You can create it using your favorite text editor (e.g. Notepad or Emacs).

For details, see https://en.wikibooks.org/wiki/Celestia/STC_File

[Danny Lorraine II]

i've made an .stc file on the largest stars

i might uplaod it to the motherlode once i get good textures

[Joey P.]

Can someone suggest a *well known* star which is *much* smaller than our Sun, excluding Proxima Cen ?

Sirius B, Van Maanen, IK Pegasi B, and Wolf 359.

Added after 3 hours 10 minutes:

- Antares (huge and unacceptable difference) -- Celestia 493.56 Sol, elsewhere : 700 Sol.

Antares was once thought to be between 280 to 700 sol.

[Joey P.]

[content deleted]

[Joey P.]

No offense, but this addon needs an update as the forum becomes Celestia's main repository for addons. The Motherlode is, unfortunately, dying.

[SpaceFanatic64]

All hope isn't lost, someone could make a new Motherlode.

[Joey P.]

But I'm really looking for an updated version of this addon.

[john71]

We should make a torrent out of the whole Motherload data .

[Anthony_B_Russo10]

Or a .7z archive.

[onetwothree]

Or a .7z archive.

Are you kidding? It's 54GB total.

We should make a torrent out of the whole Motherload data .

I've downloaded it. But 54GB..., will we have enough volunteers to download and seed such huge torrent?

[Anthony_B_Russo10]

How about making a .7z archive out of each section rather then one giant file.

[SpaceFanatic64]

I'd rather go for the .7z archive, as I don't really trust torrents that much.

[Joey P.]

I agree about the .7z archive. Or why not "merge" each author's addons to here? I've seen a list of Cham's addons as a post.

[Joey P.]

Another very good idea, looks really great. But you can use it to show more than just sizes! This is a very good moment to show shapes of stars and their changes too. Giants in general are not perfectly spherical - it's impossible on this scale! Maybe you should try to make a giant as a combination of a few spheres which rotate around its "centre of mass"? Here is a numerical simulation of Betelgeuse's shape:

http://www.aip.de/~mst/pub_files/images ... 0086_E.gif
http://www.aip.de/~mst/pub_files/images ... _I1brm.jpg

There are movies somewhere too, I dont have a link to them - if you want I can send them to you (timescale of changes and their sizes are important).

I think it would be a good idea to add Altair or Achernar due to their elongated shape.

http://www.jb.man.ac.uk/news/starshape/im2.gif

AFAIK Deneb rotates very fast, it should be elongated too.

I mean you shouldnt put all these stars in your extension, but it would be really useful to see stars which differ in sizes AND shapes.

And something about VV Cephei:

"The three stars with the largest known sizes are KW Sagitarii (distance 9,800 light-years), V354 Cephei (distance 9,000 light-years), and KY Cygni (distance 5,200 light-years), all with radii about 1500 times that of the Sun, or about 7 astronomical units(AU). For comparison, the red super-giant star Betelgeuse is known from other work to have a radius about 650 times that of the Sun, or about 3 AU. If one of these stars were placed in the sun?€™s location, its outer layers would extend to midway between the orbits of Jupiter (5.2 AU) and Saturn (9.5 AU). The previous record holder, mu Cephei comes in a close fourth in size in the study. The only other star for which a very large size has been claimed is the binary star system VV Cephei, which consists of a red super-giant and a hot companion orbiting within a common gaseous envelope, in which the gravitational forces of the companion have distended the surface of the super-giant and the meaning of the size of the star is therefore fuzzy. None of the stars in the new study are believed to be binaries, and thus their properties tell us about the extreme sizes that normal stars reach."

http://www.noao.edu/dir/proj-rep/proj-rep-05.pdf

I don't think you have to abandon the idea of this in the next version of Celestia. Celestia gives Altair and Vega their non-spherical shapes.

[Joey P.]

Here's a newer comparison addon, featuring all planets (not by me):
viewtopic.php?f=23&t=19861&p=145645#p145645