Sun vs. Planets - size comparison script

Bob Hegwood · Post #21by **Bob Hegwood** » 17.11.2003, 00:36

Don and Christoria,

I have added the final version of your Planetary Size Comparison Script to my web page at: http://www.home.earthlink.net/~bobhegwood

I've also added Mr. Hutchison's revised locations files for those of you interested in such things.

Note on the Location Files... It seems that Mr. Laurel has not finished with this project yet, since many of the location type codes have not yet been implemented. Catena (A series or range of craters) is not yet utilized in Celestia, even though the code is recognized by the system. After much experimentation and coding, it seems that we're currently limited to selecting montes (Mountains), vallis (Valleys), craters, Terrae (Land Masses), and a couple of other selections. This is good, however... If you wish to view ONLY the mountains on Mars, or ONLY the craters on the Moon, for example, you can now do that. The rest of the features (Catena for example) can only be viewed when the "Other Features" menu selection has been checked.

Again, a few of these location files may be found at the link above.

Hope that helps someone...

Take care, Bob

Darkmiss · Post #22by **Darkmiss** » 17.11.2003, 02:35

I just had a go of this script
And I must say i like it very much

Thanks to Christoria and Don
good work.

Bob Hegwood · Post #23by **Bob Hegwood** » 17.11.2003, 04:47

That's okay Paul...

You don't have to thank *me* for the 12 hours or so that *I* put into this project. Sheesh! :wink:

Take care, Bob

don · Post #24by **don** » 17.11.2003, 06:29

Bob Hegwood wrote:That's okay Paul...

You don't have to thank *me* for the 12 hours or so that *I* put into this project. Sheesh!

Take care, Bob

Only 12 hours? Geee, that's just a kick in the bucket <jokingly laughing out loud>.

LOTS of trial and error was the only way to arrive at the final values Bob used in his modifications. Trial and error is also the only way to do lots of other things, like text placement and duration, since .CEL scripting is by no means a full-blown programming language. So, certain tasks can be quite time-consuming, especially testing and debugging <smile>.

I'm gonna go have a look at your final version now Bob...

-Don G.

don · Post #25by **don** » 17.11.2003, 08:52

Howdy Bob and Everyone,

Thanks for your final version of this script!

When run with the basic Celestia distribution package, there are some timing and distance problems, so I too made a "final" version of this script that runs perfectly with the basic distribution. It can be found on my Celestia web page (http://www.donandcarla.com/Celestia/), downloaded here (http://www.donandcarla.com/Celestia/cel_scripting/SunAndPlanetsSizeComparison_1_0_3.cel.txt), or copied and pasted from the top message on page 1 of this topic.

Bob Hegwood wrote:I've also added Mr. Hutchison's revised locations files for those of you interested in such things.

You might also want to post this announcement in the User's forum.

-Don G.

Darkmiss · Post #26by **Darkmiss** » 17.11.2003, 21:29

Bob Hegwood wrote:That's okay Paul...

You don't have to thank *me* for the 12 hours or so that *I* put into this project. Sheesh!

Take care, Bob

Oh! very sorry Bob, I thought Christoria was the original author, and Don adding some flare.

Thanks to you too Bob, and anyone else who may have had a hand in it too. :lol:

Bob Hegwood · Post #27by **Bob Hegwood** » 18.11.2003, 08:06

Sorry, Paul...

You *know* how DEFENSIVE I can be,,,

Take care, Bob

Bob Hegwood · Post #28by **Bob Hegwood** » 18.11.2003, 08:29

don wrote:Howdy Bob and Everyone,

Thanks for your final version of this script!

When run with the basic Celestia distribution package, there are some timing and distance problems, so I too made a "final" version of this script that runs perfectly with the basic distribution.

I'm gonna download it and see what the differences are Don. There just HAS to be some logical reason for the distance and timing differences. Maybe we can figure it out. :cry:

By the way, I'm now designing a "killer" Mars touring script... It's based loosely on one of Mr. Ball's old projects, but with what I've learned about locations now, I'm getting some really neat features out of Pre11. I'll give you a look at it before I post it on my page or here on the Forum. Should be finished by this weekend I hope.

Take care, Bob

Post #29by **selden** » 18.11.2003, 13:26

Mr. Hegwood,

As someone else said, "Mr..." is my father.
Such formality really isn't necessary and is rather disconcerting. While some people lament the informality of modern electronic discourse, I'm not one of them.

*pfui* to formality, say I!

Bob Hegwood · Post #30by **Bob Hegwood** » 18.11.2003, 17:42

Sorry Selden...

This is a habit I picked up long ago to show my RESPECT for someone who has contributed greatly to my store of knowledge. My apologies...

While I'm here though, do you know of any reason why the latitude/longitude values in your original Mars.cel script would be in error? Olympus Mons, for example, is not shown on my display when I run your original script - even though the text says it should be. When I plug in the values I stole from the mars_locs.ssc, Olympus Mons shows up precisely in the center of my screen.

Probably been modified or something?

At any rate, I'm having a ball playing with this new location feature. Thanks again for all your help.

Bob Hegwood · Post #31by **Bob Hegwood** » 18.11.2003, 17:53

Don,

I've downloaded the latest Size Comparison script from your site, and here's what I found on my machine...

The 2 million distance are *all* accurate to within 500 km. This - I assume - is also true on your machine?

The only real difference I found was that our viewing distances from Uranus are off. Yours is 181000 km or so, and mine is roughly 179000.

I'm using an addon for Uranus' Rings and texture, but as far as I can tell, that's the only difference. Curiously, I'm also using similar addons for Jupiter, Saturn and Neptune, but we're atill arriving at the same distances. Let me have a closer look at the Uranus addons.

By the way, I've also changed Pluto's radius back to the suggested 1151 km... I'm *still* curious though. Why would the Nine Planets Organization be using 1137 km? Presumably, they're as smart as we are...

Take care, Bob

don · Post #32by **don** » 19.11.2003, 02:28

Howdy Bob,

Yes, the distance difference is the initial distance at Uranus. Unknown why.

The timing differences are the spots on Jupiter and Neptune. Unknown why.

Yes, the 2M km distances all looked good to me. Thanks!

Bob wrote:I'm *still* curious though. Why would the Nine Planets Organization be using 1137 km?

Not sure. Maybe you could write a note to them asking why, and use Selden's URLs as the reason you are asking?

-Don G.

don · Post #33by **don** » 19.11.2003, 02:34

Howdy Bob,

Bob Hegwood wrote:There just HAS to be some logical reason for the distance and timing differences. Maybe we can figure it out.

I sure hope so. You are using pre 11 right? Windows? Though I can't imagine a different OS producing this. It *would* be nice to have *one* script work exactly the same "across the board".

Bob Hegwood wrote:By the way, I'm now designing a "killer" Mars touring script...

Sounds like a fun project! One note about using older scripts ... as time progresses, Celestia gets more and more accurate with regards to the celestial mechanics stuff, so this might make an older script not quite as "exacting" as it could be on today's Celestia.

Have fun!

-Don G.

Bob Hegwood · Post #34by **Bob Hegwood** » 19.11.2003, 06:47

Don wrote:I sure hope so. You are using pre 11 right? Windows? Though I can't imagine a different OS producing this. It *would* be nice to have *one* script work exactly the same "across the board".

Pre 11, Windows XP See below...

Let's look first at the obvious. What radius are you using for Uranus? Dumb question maybe, but perhaps mine got changed somehow. Right now, on my system, Uranus is set at 26200...

Just a thought. As for the Great Spot on Jupiter, that works fine. It's the spot on Neptune that does not display at all during the latest script's duration at the planet. Hmmm... More investigation needed here.

Thanks, Bob

Bob Hegwood · Post #35by **Bob Hegwood** » 19.11.2003, 07:12

Better yet, Don, I've attached the appropriate Solarsys.SSC values for Uranus and Neptune below. Notice anything different from your version of Celestia's Solarsys.SSC?

Code: Select all

"Uranus" "Sol"
{
   Texture "uranus.jpg"
   Color [ 0.75 0.85 1.0 ]
   HazeColor [ 0.5 0.8 1.0 ]
   HazeDensity 0.2
   Radius 26200
   Oblateness 0.024

   CustomOrbit "vsop87-uranus"
   EllipticalOrbit
   {
   Period           84.0139
   SemiMajorAxis    19.1913
   Eccentricity      0.0472
   Inclination       0.7699
   AscendingNode     74.230
   LongOfPericenter 170.964
        MeanLongitude    313.232
   }

   RotationPeriod        17.24 # System III (magnetic field)
   Obliquity             97.81
   EquatorAscendingNode 167.76
   RotationOffset       331.18 # correct System III prime meridian

   Albedo            0.66

   Rings {
      Inner  41800
      Outer  51149
      Texture "uranus-rings.png"
   }
}


"Neptune" "Sol"
{
   Texture         "neptune.jpg"
   Color         [ 0.75 0.75 1.0 ]
   HazeColor      [ 0.6 1 0.75 ]
   HazeDensity      0.35
   Radius         24764
   Oblateness      0.01708

   CustomOrbit "neptune"
   EllipticalOrbit
   {
      Period       164.793
      SemiMajorAxis    30.06896348
      Eccentricity    0.00858587
      Inclination    1.76917
      AscendingNode    131.72169
      LongOfPericenter 44.97135
      MeanLongitude    304.88003
   }

   RotationPeriod      16.11
   Obliquity      28.32
   LongOfRotationAxis   49.235

   Albedo         0.41

   Rings
   {
      Inner    41900
      Outer    62983
      Texture   "neptune-rings.png"
   }
}

Take care, Bob

Bob Hegwood · Post #36by **Bob Hegwood** » 19.11.2003, 07:40

don wrote:
Bob wrote:I'm *still* curious though. Why would the Nine Planets Organization be using 1137 km?
Not sure. Maybe you could write a note to them asking why, and use Selden's URLs as the reason you are asking?

Did a little more investigation on the Nine Planets site with some interesting results...

"Pluto's radius is not well known. JPL's value of 1137 is given with an error of +/-8, almost one percent."

Just thought I'd share that with you...

-Bob

don · Post #37by **don** » 19.11.2003, 07:54

Howdy Bob,

Good call !

Yes, there are LOTS of differences. Remember, mine is from the basic Celestia distribution, without any add-ons or mods.

-Don G.

Code: Select all

Uranus Differences:

Texture "uranus.*"
Radius 25559 # equatorial
Oblateness 0.0229

Uranus-In mine but not in yours:
  Atmosphere {
    Height 130
    Lower [ 0.75 0.85 1.0 ]
    Upper [ 0.5 0.8 0.9 ]
    Sky [ 0.6 0.7 0.7 ]
  }

Code: Select all

Neptune Differences:

  Texture "neptune.*"
  Radius 24766 # equatorial
  Oblateness 0.017

  CustomOrbit "vsop87-neptune"

  SemiMajorAxis     30.0690
  Eccentricity      0.0086
  Inclination       1.7692
  AscendingNode   131.722
  LongOfPericenter 44.971
  MeanLongitude   304.880
  Obliquity             28.03
  Albedo                 0.62

Neptune-In mine but not in yours:
  Atmosphere {
    Height 130
    Lower [ 0.6 0.65 1.0 ]
    Upper [ 0.5 0.55 0.9 ]
    Sky [ 0.5 0.7 0.9 ]
  }
  EquatorAscendingNode  49.235
  RotationOffset       228.65 # correct System III prime meridian

Neptune-In yours but not in mine:
  LongOfRotationAxis   49.235 

  Rings 
    { 
    Inner    41900
    Outer    62983 
    Texture   "neptune-rings.png" 
    }

Bob Hegwood · Post #38by **Bob Hegwood** » 19.11.2003, 08:13

Well now we're getting somewhere...

You know, I'm starting to think that I may have screwed up my version of Pre11 when I installed it. Now that I think about it, I may have even copied the 1.3.0 SolarSys.SSC file to the new version thinking that THAT way, I wouldn't lose my changes. (Okay, okay... I already *know* I'm an idiot now!) :roll:

Is there somewhere that I can download just the solarsys.SSC file for Celestia 1.3.1 Pre11? CVS maybe?

At any rate, I'll have a look see at what you've provided, and see if *that* explains the differences.

Thank you Mr. Goyette! You're a gentleman and a scholar. :lol:

Aw... hell, yer an old geezer like me, but I *really* appreciate the input. I'll let you know if these changes could be causing our differences in the script. It certainly LOOKS as if they might be responsible.

Thanks again Sir.

Take care, Bob

don · Post #39by **don** » 19.11.2003, 08:38

Howdy Bob,

You can get any of the distribution data files from CVS, and also from Christophe's great Cross Reference page, for example, here:
http://celestia.teyssier.org/lxr/source/data/extrasolar.ssc

I think I did the same thing (copied my old .ssc file) the first time I installed an updated version too. Just a minor newbie error.

Bob wrote:Aw... hell, yer an old geezer like me

Now THIS is more like it! :lol:

Save the "Mr." stuff for when it really counts, whenever that might be. :wink:

-Don G.

PS. I use the "G." so my posts are not confused with Don Edwards, who signs his messages "Don".

Bob Hegwood · Post #40by **Bob Hegwood** » 19.11.2003, 17:47

Don,

Almost everything works the same way on my machine now...
The only difference is that the dark spot on Neptune still doesn't rotate around to the display when it should.
Since I had to change the solarsys.ssc file when I installed the Neptune addon, I'm simply going to have to try each of the lines one at a time in order to see which one is the culprit.

So what have we learned here?

First, one should *never* keep an old ssc file, except in a separate directory somewhere as a reference point to re-enable old addons.
Second, textures and ring systems have *no* effect on distance and timing calculations. (At least as far as I could tell.) Another thought though... Perhaps *my* Neptune.jpg file is a different picture of Neptune. In other words, perhaps the dark spot may be located at the end of the texture, rather than the beginning. I'll find out.
Third, planetary radii may *change* with different versions of Celestia since they are *not* as "set in stone" as I once thought they were.

Not too bad for my first real experimentation with scripts. :wink:

Thanks again, Don. When I figure out what the deal is with the Neptune Dark Spot, I'll let you know.

Take care, Bob