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Gravity Simulator
10/20/18 at 19:48:17
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1  General / Discussion / Re: Moon orbit - max distance
 on: 10/18/18 at 16:14:01 
Started by wil | Post by wil
Ok.
Thus what is the real maximum distance in the case of the Moon, or in general: in any three-body scenario?
 
Hill by 2, 3, maybe e?
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2  General / Discussion / Re: Moon orbit - max distance
 on: 10/18/18 at 15:29:55 
Started by wil | Post by Tony
Hill Sphere is sometimes mistakenly interpreted as the volume with which an object can orbit. It is not.
In prograde orbits, objects can orbit out to about 1/3 of a Hill Sphere. In retrograde orbits, they can exceed 1/2 Hill Sphere. Anything past this and the Sun will strip them away.
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3  General / Discussion / Moon orbit - max distance
 on: 10/18/18 at 13:32:04 
Started by wil | Post by wil
The Hill sphere for the Earth is about 1.5 mln km.
 
But when I try to set only two times bigger distance to the Moon: 2x400 = 800 only, then the Moon escapes from the Earth immediately.
 
This is something wrong in the GS, or the Hill sphere is a nonsense?
 
This is about 1/3 of the Hill's distance possible for stable lunar orbit, thus about: 500 = 0.5 mln km only, maybe 550 !
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4  General / Discussion / Re: 300 Error when trying to access old threads...
 on: 08/12/18 at 03:26:49 
Started by stargate38 | Post by frankuitaalst
Hi Stargate,  
 
I checekd :  
Funny result : the posts "gravity assist " cannot be openend indeed .  
However if I perform a search for "assist " I get the posts listed in the search output and can see them in prview  .  
The posts themselves however cannot be openend . This means the posts aren't really lost I guess ....
 
Frank
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5  General / Discussion / Re: 300 Error when trying to access old threads...
 on: 08/02/18 at 10:01:19 
Started by stargate38 | Post by stargate38
I know you don't know how to recover them, but the text above the forum says "New Members need to post in the welcome thread within 24 hours from account activation to complete confirmation", which is impossible because the thread is inaccessible. Why are whole threads suddenly deleting themselves? Huh It shouldn't be happening. Maybe you should create a whole site backup, or something similar, just in case the whole forum goes down. Your server might have a failing hard drive, or some other form of corruption. You don't want the whole forum suddenly vanishing with no backups.
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6  General / Discussion / Re: 300 Error when trying to access old threads...
 on: 07/29/18 at 12:19:51 
Started by stargate38 | Post by Tony
Same answer as last time. I didn't write the forum software. I don't have a clue as to how to recover deleted messages. New users have to email me for an account because too many robots were making accounts.
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7  General / Discussion / Re: Autopilot in the browser version
 on: 07/29/18 at 12:17:38 
Started by Tony | Post by Tony
The Quick Help dialog box is for giving simple instructions to the user. You can change the color and size in Autopilot Now.
Code:
txtAreaQuickHelp.style.backgroundColor = '#440000';
txtAreaQuickHelp.style.color = '#FF00FF';

txtAreaQuickHelp.style.height = '150px';
divQuickHelp.style.height = '150px'; 

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8  General / Discussion / Re: 300 Error when trying to access old threads...
 on: 07/25/18 at 14:52:58 
Started by stargate38 | Post by stargate38
Sorry for bumping up an old thread, the Welcome (Terms of Use) thread is giving me the same error as the others. Please fix it. If you don't, new users won't be able to activate their accounts, which is a major problem for this forum, as it blocks legit users as well. Also, the "Insert Flash" button isn't coming up for me.
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9  General / Discussion / Re: Autopilot in the browser version
 on: 07/18/18 at 14:22:13 
Started by Tony | Post by Tony
This code will create an object from an MPEC. Place it in the Autopilot Now interface, and paste the contents of the MPEC into the Quick Help dialog box.
 
For example, go to the page: https://www.minorplanetcenter.net/mpec/K17/K17L08.html
Copy the contents of the page (not the source code) and paste it into Quick Help.
Open Objects > Create Objects. Make sure the reference objects is correct.
Make sure the simulation's epoch matches the epoch of the MPEC.  
 
Open Autopilot Now and paste the following code. Press Apply.
It will change the units for SMA to AU.
It will then populate the Create Objects interface with the object's name, and its 6 orbital elements.
Press Create.
 
This method may not save a lot of time vs. copying and pasting the name and elements individually, but it will eliminate the high chance of making a typo.
Code:
	var inString = txtAreaQuickHelp.value;
	var pos1 = inString.indexOf("Orbital elements:");
	var pos2 = inString.indexOf(String.fromCharCode(10), pos1);
	var pos3 = inString.indexOf(String.fromCharCode(10), pos2+1);
	var oName = inString.substring(pos2+1, pos3);
	
	// Find M
	var pos4 = inString.indexOf("M ", pos3);
	var pos5 = inString.indexOf(".", pos4);
	var pos6 = inString.indexOf(" ", pos5);
	var M = inString.substring(pos4+1, pos6);
	M = M.trim();
	
	// Find peri
	var pos7 = inString.indexOf("Peri. ", pos6);
	var pos8 = inString.indexOf(".", pos7+5);
	var pos9 = inString.indexOf(" ", pos8);
	var peri = inString.substring(pos7+5, pos9);
	peri = peri.trim();
	
	// Find a
	var pos10 = inString.indexOf("a ", pos9);
	var pos11 = inString.indexOf(".", pos10);
	var pos12 = inString.indexOf(" ", pos11);
	var a = inString.substring(pos10+1, pos12);
	a = a.trim();
	
	// Find Node
	var pos13 = inString.indexOf("Node ", pos12);
	var pos14 = inString.indexOf(".", pos13);
	var pos15 = inString.indexOf(" ", pos14);
	var node = inString.substring(pos13+4, pos15);
	node = node.trim();
	
	// Find e
	var pos16 = inString.indexOf("e ", pos15);
	var pos17 = inString.indexOf(".", pos16);
	var pos18 = inString.indexOf(" ", pos17);
	var e = inString.substring(pos16+1, pos18);
	e = e.trim();
	
	// Find Incl.
	var pos19 = inString.indexOf("Incl. ", pos18);
	var pos20 = inString.indexOf(".", pos19+5);
	var pos21 = inString.indexOf(" ", pos20);
	var i = inString.substring(pos19+5, pos21);
	i = i.trim();
	
	
	// below is used for Autopilot. It will paste the orbital elements into the Create Objects interface. User must make sure the epochs match, make sure the units for SMA are correct, and make sure Reference Object is correct.
	txtCreateName.value = oName;
	txtSMA.value = a;
	txtEccentricity.value = e;
	txtInclination.value = i;
	txtLongitude.value = node;
	txtPeriapsis.value = peri;
	txtMA.value = M;
	
	while (btnSMAUnit.value != "(AU)") {btnSMAUnit.click()}
 

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10  General / Discussion / Re: Scholz's Star Ref WISE J0720-0846
 on: 04/08/18 at 12:42:22 
Started by grahamjohnson10 | Post by Tony
http://orbitsimulator.com/gravitySimulatorCloud/simulations/1523215795749_WISE_J 0720_0846.html
All I could find is its distance and RA & Dec. The uncertainty in the distance is probably high. Without any information on the speed, this is the best I can do. I've set it to have 0 velocity wrt the Sun.
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