Opinions: dwarf planets and minor moons

[chris]

I've added new object classes called minormoon and dwarf planet. Minor moon exists to reduce some of the orbit and label clutter from all the rocks orbiting the outer planets. If you set the class of a moon to minormoon, its orbit and label will not be shown unless you enable minor moon orbits and labels. The same behavior will apply for dwarf planets: their labels and orbits can be toggled independently of planets.

For label toggle keys, I think shift+m and shift+p make the most sense for minor moons and dwarf planets. Sensible?

Some other questions:

- Should the label/orbit colors be the same for moons as minor moons; my sense is that they should be the same colors.
- Same question for dwarf planets: identical label/orbit colors as for planets?
- I'm not that enthusiastic about actually changing the classes of Ceres, Pluto, and Eris to dwarf planet. It's not that I have strong opinions either way on the IAU decision; I just don't want to mess with the classes if the resolution of 2006 gets overturned in 2006. Does anyone actually care about this whole dwarf planet thing? (Careful: I'm asking about this in the context of Celestia, not trying to stir up the whole is-Pluto-a-planet debate. Impassioned statements about the planethood of any solar system body will be deleted from this thread.)

--Chris

[selden]

The support described for minor moons and minor planets seems reasonable to me. Although there are few minor-planets now, the number could grow, and I think it'd be good to be able to distinguish them.

[ElChristou]

Concerning Ceres and co, it depends if it's too much work to do or not; if not IMHO I would say let's go because if I'm not wrong official publications have already change their entries. I say if it's not too much work because then reverting would be easy...

For minor moons versus moons colors, why a light declination of the moon color? just to mark the 2 groups? Don't need to be different, just a tone or two up or down... no?

For dwarf planets same thing, I would say same palette as planets, a tone or two up or down...

[Adirondack]

I do agree with Selden and ElChristou (minor moons versus moons colors).

Adirondack

[ElChristou]

BTW, do the GUI need some new checkbox for those classes?

[chris]

BTW, do the GUI need some new checkbox for those classes?

Yes, the GUI will need to be updated.

--Chris

[ANDREA]

I've added new object classes called minormoon and dwarf planet. ....Some other questions:...identical label/orbit colors as for planets?--Chris

Chris, actually in my "The new Solar System show" I'm compelled to define Pluto, Ceres and Eris Dwarf planets as spacecraft, so giving them a different label/orbit color.
Burt this can be impossible in other situations.
So I would prefer, if this is not a big programming problem, to have dwarf planets as a different class with its own label/orbit color, possibly.
However it's not a must-be change, IMHO.
Bye

Andrea

[Cham]

I advocate for some new orbit and label colors, for each new class. The dwarfplanet and minormoon should have their own orbit and label color, defined in the start script. The user could then use the same color as for the planets, if he/she wants to. I prefer a different color, so we can clearly see the difference.

I agree with the shift-m and shift-p keyboard shortcuts.

[bdm]

What is the definition of a minor moon?

[chris]

What is the definition of a minor moon?

It's arbitrary. The idea is to eliminate the clutter of orbits and labels around the outer planets when moon orbits are enabled. In most cases, you're just interested in the larger moons that generally orbit in the equatorial plane of the planet. The cloud of rocks in orbit around the gas giants are just a distraction 99% of the time, but every once in a while it's interesting to have a look at them. The minormoon class provides a way to filter them out without actually removing them from the ssc files.

Grant pointed out that there are really two classes of 'minor moons': small satellites that orbit close to the planet in the equatorial (such as the ring shepherd moons) and distant irregular satellites that tend to have very inclineds. But, to avoid overwhelming the user with options, I've implemented just one minor moon class for both these types of object.

--Chris

[Kolano]

• While the existing data files may contradict this, I'd personally like to define "minor-moon" as a moon without an official name (i.e. numbered moons). That may provide a more concrete definition than currently proposed.
  
• Regarding orbit color, I feel moons/minor moons and planets/dwarf planets should be of the same "color" (i.e. red, blue, purple) but of differing shades so that they can be distinguished from one another (i.e. moons are dark blue, minor-moons light blue). Label color should match orbit color.
  
• Ceres, Pluto, and Eris should be dwarf planets. If the IAU decision is reversed then they should reverse back, but until then they are dwarfs.

[ElChristou]

Do each entries in minormoons.ssc and numberedmoons.ssc need to be edited adding the minormoon class?

[chris]

Do each entries in minormoons.ssc and numberedmoons.ssc need to be edited adding the minormoon class?

Yes, they all need to be edited and assigned the class minormoon. I could add some code to do it automatically (e.g. anything with a radius less than 1/1000th of its parent's is a minormoon), but any such criterion has weird holes or cutoffs. It's better if the maintainers of the data files are explicit about what is a minor moon, as ultimately there's no clear natural boundary between moon and minor moon. The decision is clear with some objects, such as when comparing Titan to Ymir, an 18km rock orbiting Saturn in an eccentric retrograde orbit with a semimajor axis of 23 million km. But what about the co-orbital satellites of Dione and Tethys? Are they minor satellites because of they're size? Or major satellites because the have regular orbits? Given the challenges involved in making an automatic categorization based on size and orbits, I feel it's best to simply leave it to us humans.

--Chris

[chris]

• While the existing data files may contradict this, I'd personally like to define "minor-moon" as a moon without an official name (i.e. numbered moons). That may provide a more concrete definition than currently proposed.
  

No. The whole point of the minor moon category is to eliminate orbit and label clutter. Saturn has 60 named satellites; showing all of their orbits still leaves the Saturn system looking rather busy.

Regarding orbit color, I feel moons/minor moons and planets/dwarf planets should be of the same "color" (i.e. red, blue, purple) but of differing shades so that they can be distinguished from one another (i.e. moons are dark blue, minor-moons light blue). Label color should match orbit color.

For dwarf planets, I agree with you. Since there's no official distinction between moons and minor moons, I'm not sure it's right to give them different orbit colors. On the other hand, it would be helpful to highlight the primary satellites.

Ceres, Pluto, and Eris should be dwarf planets. If the IAU decision is reversed then they should reverse back, but until then they are dwarfs.

Agreed.

--Chris

[chris]

I've added new object classes called minormoon and dwarf planet. ....Some other questions:...identical label/orbit colors as for planets?--Chris

Chris, actually in my "The new Solar System show" I'm compelled to define Pluto, Ceres and Eris Dwarf planets as spacecraft, so giving them a different label/orbit color.
Burt this can be impossible in other situations.
So I would prefer, if this is not a big programming problem, to have dwarf planets as a different class with its own label/orbit color, possibly.
However it's not a must-be change, IMHO.

Yes, I will give them different colors. It's not at all a hard thing to do.

--Chris

[ANDREA]

So I would prefer, if this is not a big programming problem, to have dwarf planets as a different class with its own label/orbit color, possibly. However it's not a must-be change, IMHO.

Yes, I will give them different colors. It's not at all a hard thing to do.
--Chris

Thank you, Chris, appreciated.
Bye

Andrea

[Vincent]

I've added new object classes called minormoon and dwarf planet. ....Some other questions:...identical label/orbit colors as for planets?--Chris

Chris, actually in my "The new Solar System show" I'm compelled to define Pluto, Ceres and Eris Dwarf planets as spacecraft, so giving them a different label/orbit color.
Burt this can be impossible in other situations.
So I would prefer, if this is not a big programming problem, to have dwarf planets as a different class with its own label/orbit color, possibly.
However it's not a must-be change, IMHO.

Yes, I will give them different colors. It's not at all a hard thing to do.

--Chris

Chris,

I've added the Dwarf Planet and Minor Moon label/orbit settings to the QT4 and Windows UIs.
I also made the required change to the orbit/label renderer in order to test my changes.
This should save you a few minutes of coding...
Now, we just need to agree on the label and orbit colors for these two new classes...

[chris]

Chris,

I've added the Dwarf Planet and Minor Moon label/orbit settings to the QT4 and Windows UIs.
I also made the required change to the orbit/label renderer in order to test my changes.
This should save you a few minutes of coding...
Now, we just need to agree on the label and orbit colors for these two new classes...

Thanks, Vincent. I've checked in the core changes, the keyboard bindings, and the Qt4 solar system browser changes. So go ahead and commit the UI changes whenever you're ready.

--Chris

[cartrite]

Chris,
I just built r4275. And no for others out there, I did not update my site yet.
I made the following change to minormoons.ssc from the extras folder.

Code: Select all

"Metis" "Sol/Jupiter"
{
   Class "MinorMoon"
   Texture       "asteroid.jpg"
   SemiAxes [ 30 20 20 ]

   EllipticalOrbit
   {
   Period      0.294780
   SemiMajorAxis   127979
   Eccentricity   0.0012
   Inclination   0.019
   AscendingNode   263.953   #
   ArgOfPericenter 274.588   # J2000.0
   MeanAnomaly   7.649   #
   }



When I toggle M nothing seemed to happen until I went to Metis. I toggled m and lit up all the moon labels. Then when I toggled M, the Metis label disappeared and reappeared. But if I togged m to turn the labels off on all moons, toggling M had no affect.
Is this how it is supposed to work?
cartrite

[ajtribick]

What is the default class for objects in orbit around dwarf planets: moon or minormoon?