Bill Gray Mar 8, 2013
On 03/05/2013 04:48 PM, dkoschny wrote:
> Hello, I am playing with the possibility of using the combination of
> Find_Orb and Guide to visualize the impact ground track of asteroids.
> I am running 2011 AG5 with pre-October observations when it had a
> chance of 1/500 to hit the Earth. As expected, I find only a few
> entries in the 'virtual.txt' file. But only some of them give
> longitude/latitude on the Earth.
True. 'virtual.txt' will give orbital elements for all of the
variant objects (not just the impactors). The impactors will have
a bit of extra text giving the impact time and lat/lon.
> So what are the criteria when an orbit ends up in this file?
Simply that it impacts the earth.
> And what are the columns? Some I could figure out but not all.
> Is this documented somewhere?
It's not. And you're right, it should be... I'll write something
up and post here when it's ready. (And will fix something I just
noticed: if the eccentricity is greater than 1000 -- which can
happen for fast planetary flybys -- the extra digits aren't
handled properly. This occurs with C/2013 A1's possible impact
on Mars. I've not seen it elsewhere. Some format revision will
be needed to fix this. But the lat/lon/impact data should be
unaffected.)
-- Bill
>
> Thanks for pointing me to the right place!
>
> Detlef.