Celestia Forums

This addon compares the sizes of all the Solar System asteroids in Celestia, along with 3 comets, the 9 Major bodies, a Brown Dwarf, Teegarden's Star, Proxima Cen, Alpha Cen B, Sol, Sirius A, Procyon, Rigel, and an O type star. The folder contains two builds, one for 1.6.1 with the brown dwarf with spectral type T9, and one for 1.7.0 with the brown dwarf at its correct spectral type of Y2.The above image is of the 1.7.0 build.
These are of the 1.6.1 build.

Nice!

What about putting the Danny Phantom stars in it?

Remember this older one comparing various giant stars including the red giant Sun?
viewtopic.php?f=6&t=11257&p=145647#p145647

Joey P. wrote:What about putting the Danny Phantom stars in it?

The point of the add-on was to compare the sizes of various (real) astrophysical objects.

Joey P. wrote:What about putting the Danny Phantom stars in it?

You can make your own comparison thread with the fictional stars you've made. This one's for real objects, as what Sirius_Alpha said.

Also, the object comparison is right behind Alpha Centauri as seen from Earth, but its combined apparent and absolute magnitudes are so bright that Alpha Centauri is lost in the glare.

I upped the distance of the barycenter to 1000 light years.

Nice

This is the code for a modification that slightly changes the position of the comparison and turns the base star into Danny Phantom (though 12 times smaller than he should be). It also adds "2" to the stars involved so that they are not involved in anything else.

Talking about object comparison, and apologizing for drifting a little offtopic, this topic reminded me of an issue I observed in my Celestia 1.6.0 (Yes, I know...).
Once upon a time, in a not so far away galaxy, I had the idea of making a comparison of object sizes putting them side by side in a vertically splited view. To my total surprise, I observed that a Brown Dwarf with a radius of 74400Km was visually larger than a planet with a radius of 78171Km, both seen from the same distance and FOV. Please, see the image below.

Well, I figured out that the issue arises in the planet side. When one calculates the angular diameter for the Brown Dwarf, the value is correct. The same does not happen to the planet. The angular diameter of the planet should be ~27°52' using the equation:
angdiam=2arcsin[diameter/(2*dist)]
But as you can see in the image, the apparent diameter of the planet, given by Celestia, is ~22°23'.

Is this an issue? Or a silly mistake of mine?

It's fine.

This update adds more stars:

Fabers_br wrote:Is this an issue? Or a silly mistake of mine?

The issue arises in the way Celestia calculates the "distance." For a planet, the distance is between the observer and the surface, whereas for a star, it is defined with respect to the centre of the star. If you "land" on the star's surface, you'll note you will have quite some "distance" still.

Mu Cephei, VV Cephei, and VY Canis Majoris (this uses textures only found in Celestia-ED):

Sirius_Alpha wrote:The issue arises in the way Celestia calculates the "distance." For a planet, the distance is between the observer and the surface, whereas for a star, it is defined with respect to the centre of the star. If you "land" on the star's surface, you'll note you will have quite some "distance" still.

Oh! Thank you, Sirius! So many years using Celestia and I had never noticed that! Shame on me.
After being enlighted on this matter, I was able to correctly display the comparison the way it was meant to be.

Full size comparison including large stars and Danny Phantom objects:

Also, how do you tweak the glow color for the stars like what you have done with the red dwarf in the first picture? Thanks.

Joey P. wrote:Also, how do you tweak the glow color for the stars like what you have done with the red dwarf in the first picture? Thanks.

It's toggled by the "%" key.

Oh, thanks!