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http://www.orbitsimulator.com/cgi-bin/yabb/YaBB.pl?num=1438215374

Message started by Tony on 07/29/15 at 17:16:14

Title: more Neptune trojans
Post by Tony on 07/29/15 at 17:16:14

D. W. Gerdes, et al discovered two more Neptune trojan asteroids. 2014 QO4441 and 2014 QP441 have the same orbital period as Neptune, and reside in the region near Neptune's L4 point. This simulation is in a rotating frame that keeps Neptune stationary.

http://orbitsimulator.com/gravitySimulatorCloud/simulations/1438214302139_NeptuneTrojans.html

Title: Re: more Neptune trojans
Post by frankuitaalst on 07/30/15 at 09:19:58

Nicely done Tony .
Seems the trojan family grows ! In may 2014 Wikipedia counted 9 trojans of Neptune , I simulated here :

http://www.orbitsimulator.com/cgi-bin/yabb/YaBB.pl?num=1233500541/24#24

Now ,in 1 year time the number is 13 .
Congrats for the animation .
The code also keeps Neptune stationary which is an improvement imo .

Title: Re: more Neptune trojans
Post by Tony on 07/30/15 at 11:42:47

Neptune's trojan family will probably continue to increase.  It may have as many as Jupiter.
You can simulate all of them by starting here:
http://orbitsimulator.com/gravitySimulatorCloud/simulations/orbitViewer.html
and typing their names, separated by commas in the Import box.

Or just copy and paste:
2001 QR322, 2004 UP10, 2005 TN53, 2005 TO74, 2006 RJ103, 2007 VL305, 2008 LC18, 2004 KV18, 2011 HM102, 2010 EN65, 2012 UV177, 2014 QO441, 2014 QP441, 2005 TN74, 2007 RW10

Then in the dropdown list choose Neptune barycenter.

Title: Re: more Neptune trojans
Post by frankuitaalst on 07/30/15 at 12:34:06

Thanks Tony , the viewer works fine !
I imported all of the given trojans , they are inserted smoothly .
I , however , have a remarkable result : in rotating frame the 2007 RW10 Trojan seems to circle Neptune , i.e it is not in L4, nor L5 nor is on a horseshoe .
Do you get the same result ?

( Or have I been importing the new bodies when the sim already had started ...) .
How do you manage to import bodies ? I mean : the x,y,z, vx,vy, vz must be inserted in the sim at the time the sim is .

Question concerning representation : the orbit representation changes when the body is under or above the "ecliptic" .
Is it possible to turn this feature off somehow ?

Title: Re: more Neptune trojans
Post by Tony on 07/30/15 at 15:03:01

2007 RW10 is a quasi satellite, not trojan.  I shouldn't have included it.  If it escapes quasi, it may become trojan or horseshoe.
You can import objects while the sim is running, but JPL Horizons doesn't give data beyond this century, so its best to import while paused and at a current epoch.
When you import, it sends a request to JPL Horizons, which sends x,y,z, vx, vy, vz back to the program.

The orbits turn darker when below the ecliptic.  You can change this.  Pause the simulation, then type "E" for edit object (or type "M" for menu and choose Objects > Edit Objects).
Choose an object and make its trail color and its "sub-z" color the same.

You can also save your simulations.  Press "M" for menu, then File > Save As
There are 3 ways to save:
1. check "Create temporary link".  This saves it on the orbitsimulator.com server, but the link is only visible to you.
2. check "Share on orbitsimulator.com".  This saves it on the orbitsimulator.com server and places on the page http://orbitsimulator.com/gravitySimulatorCloud/simulations
3. copy the code under where it says "source code".  Paste this into notepad or wordpad, and save it as plain text with a ".html" extension.  You can then run it directly off your computer without having saved it to orbitsimulator.com server.

Title: Re: more Neptune trojans
Post by frankuitaalst on 08/01/15 at 01:49:00

Tony ,
The insertion of bodies in this code works yust fine !

Fabuluous that you are able to get the data from the JPL Horizons Web interface !
If I'm not mistaken JPL generates the data out of a priorly  calculated set of polynomials as a function of time .
This is why the data are available that quick I guess.

I guess I'll add this link to my favorites , as a starting point .  
http://orbitsimulator.com/gravitySimulatorCloud/simulations/orbitViewer.html

Playing with it I personnaly have some preferences :
* when edting in a pop-up screen the screen is set transparant. This feature leaves the background visible but makes the input harder to read . May depend on the screen characteristics. I myself would prefer an opaque foreground screen.
* when having created a new sim it would be fine if I could save the file in a folder on my own pc , just as we could do in the stand alone GravSim . Can this be done ?

Title: Re: more Neptune trojans
Post by Tony on 08/01/15 at 08:29:15

The semi-transparent input fields are on my list to fix.  But until then, you can right-click on any one of them, choose "inspect element" and change their opacity to 1.
Yes, you can save it to your own computer.  See my last post.  Method #3 is for saving to your computer.  Another method is to right-click the link it generates for you when you save it, and choose "Save link as..."  This requires you have either the "create temporary link" or "share on orbitsimulator.com" checked.  But it is a little easier than copying and pasting the code into notepad and saving with .html extension.

Title: Re: more Neptune trojans
Post by frankuitaalst on 08/02/15 at 02:01:01

Thanks Tony for the clarification . I see I already added a Uranian Trojan sim on the server . Now trying to save it on my desktop as you describe...;

Concerning the editing of objects I have some  difficulty to change the color of objects in the edit menu .
The Windows color picker doesn't seem to accept color changes . Do you have the same experience ?
( the color picker window remains visible after having edited a color , and doesn't disappear )

Title: Re: more Neptune trojans
Post by Tony on 08/02/15 at 13:59:42

I don't have that trouble. Can you post a screenshot? What browser are you using?

Title: Re: more Neptune trojans
Post by frankuitaalst on 08/02/15 at 22:34:13

Item is solved . I didn't realize I had to click on a non-color field in order to get the color selection box to disappear .

Title: Re: more Neptune trojans
Post by Tony on 08/02/15 at 22:41:09

ok, now I know what you're describing.  This bothers me too.  I don't like the color picker.  I didn't write it.  I only chose it because it works in Internet Explorer, and my stats show me that I still have a lot of IE users.  There are better ones that work in Firefox and Safari, but not IE.  Maybe one day I'll write my own.

Title: Re: more Neptune trojans
Post by frankuitaalst on 08/03/15 at 13:27:10

ok , I also noticed that in the "Edit" menu two kinds of editing are available : "elements" and "vectors" . Both  have their color picker , and they seem to be synchronised , which is ok .
In fact I was looking for an instruction to render an object "invisible" ie : existing but not visible .
Is this instruction already available Tony ? Or should I look in another Menu ?

Title: Re: more Neptune trojans
Post by Tony on 08/03/15 at 16:37:16

Just set its color to black.
You can also set its size to 0, and then choose 0 pixels as the minimum object size.  Then you have to exaggerate the sizes of the objects so they show up.
What I like about HTML graphics is sub-pixeling.  You can draw something 0.3 pixels wide.  Press "A" to open the display options and you can set the minimum size of objects and their trails.

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