P. Clay Sherrod Nov 7, 2011
----- Original Message -----
From: "Bill J Gray" <pluto@...>
To: <guide-user@yahoogroups.com>
Sent: Monday, November 07, 2011 7:45 PM
Subject: Re: [guide-user] 2005YU55 path error
> Hello all,
>
> There's a very definite problem here, and John Farrell has
> diagnosed it correctly: the elements must be for an epoch close
> to that of the actual event, and MPC's default epoch will be for
> a few months away from the flyby. (*)
>
> To get around that, save this e-mail as a text file, and then
> use Extras... Asteroid/Comets Options, and then on Add MPC
> Comets/Asteroids. At the bottom, you'll see an "Add MPC Comets/Asteroids"
> option. Click on this, and then select the text file you've saved.
>
> To confirm that you got it, and that Guide isn't still using some
> other elements for 2005 YU55, right-click on the asteroid and then
> on "More Info". The epoch should be 2011 Nov 9. (Note that the object
> is currently so close to the sun as to be very, very faint. You
> may have to just turn asteroids On to get it to show up. Or set Guide's
> date/time ahead to 2011 Nov 9, when it'll be bright.)
>
> This should result in zero error for 2011 Nov 9, increasing to
> a few arcminutes by the next day... by which point I'll post fresh
> elements.
>
> (*) This is _not_ MPC's fault, though. The "correct" solution
> would be for Guide to numerically integrate the motion of the asteroid.
> If it did so, it would be accurate no matter what epoch MPC chose...
> though things might get pretty slow at times.
>
> -- Bill
>
> Orbital elements:
> 2005 YU55
> Perihelion 2011 Sep 10.258959 TT = 6:12:54 (JD 2455814.758959)
> Epoch 2011 Nov 9.0 TT = JDT 2455874.5 Earth MOID: 0.0010 Ve: 0.0003
> M 47.53070 (2000.0) Ma: 0.0367
> n 0.79561227 Peri. 270.87649 0.62715112 0.77888427
> a 1.15345785 Node 37.96499 -0.71164640 0.57537001
> e 0.4325850 Incl. 0.42437 -0.31660837 0.24957692
> P 1.24/452.47d H 22.1 G 0.15
> From 766 observations 2005 Dec. 24-2010 Apr. 20; mean residual 0".437.
>
>
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