Re: [find_orb] Impact locations - Can't reproduce 2008TC3 example

Detlef.Koschny@esa.int Feb 21, 2012

Yep, that was the missing point - uncheck the 'heliocentric orbit' toggle. Thanks! In the initial solve it only uses 252 observations - but when I press 'auto-solve' it uses all 859.

I found the NEODyS .rwo file, because you did mention it somewhere in your documentation - a bit hidden though, so yes it would be nice to have a more explicit link.

Now I just need to find out how to visualize this in Guide ;-)

Getting there... dvk


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Detlef Koschny
ESA SRE-SM
Keplerlaan 1, NL-2201 AZ Noordwijk ZH
The Netherlands
(31) 71 565 4828, Office Ca110
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-----find_orb@yahoogroups.com wrote: -----
To: find_orb@yahoogroups.com
From: Bill J Gray
Sent by: find_orb@yahoogroups.com
Date: 2012-02-21 19h13
Subject: Re: [find_orb] Impact locations - Can't reproduce 2008TC3 example

Hi Detlef,

Stefan beat me to it: you need to make sure the 'heliocentric only' check-box in
Settings is unchecked. And when you load up 2008 TC3, not all observations are
initially turned on. This happens rather often with longer arcs (2008 TC3 was
observed for less than a day, but the arc on the sky was relatively large).
In such a case, Find_Orb selects a sub-arc and does an initial orbit determination
for it.

Also, I see the documentation on the Web site mentions getting data for 2008 TC3
from MPCOBS, but doesn't mention that one can get it from NEODyS at

http://newton.dm.unipi.it/~neodys2/mpcobs/2008TC3.rwo

I'll fix the docs to mention the NEODyS link and the need to clear the 'heliocentric
only' box.

In re not all observations being turned on: in recent weeks, I've been thinking
about how Find_Orb might do arc extension (figuring out that adjacent observations
could be included, leading to still more observations being fitted). "Auto-Solve"
can sometimes do this, but it's a little bit limited. I've had some ideas for
improvement. It is possible the next update will be able, in about 99% of cases,
to load up data and completely figure out the orbit without human intervention.
(The 'problem cases' being certain artificial satellite orbits and SOHO comets;
these will probably still require some human thought.)

-- Bill

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