I know that there was a substantial error in some periodic comets that inadvertently been
assigned incorrect epochs on the last three or so daily updates. I suspect it might also
have occurred on many well observed numbered asteroids as well.

I contact Gareth at MPC last night and he has fixed the problem on the comets (i.e., 29P
was off by 2.5 days), so you might try comparing the positions on today's updates with
those issued from MPC yesterday. If the position is still in error, contact them and ask
if they are having an epoch designation issue with those asteroids as they did with some
periodic comets.

Hope this helps.

Dr. Clay
_____
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West
http://www.arksky.org/

----- Original Message -----
From: "astronomer2002" <astronomer2002@...>
To: <guide-user@yahoogroups.com>
Sent: Thursday, March 24, 2011 9:06 AM
Subject: [guide-user] Problem with asteroid positions


>I have used Guide 8 since it first came out and have rarely found any major discrepancies
>in the position of low numbered asteroids.
>
> However I plotted 210, isabella, and tried to find it last night. No asteroid down to lm
> 17 with ccd. Eventually I got an ephemeris from the minor planet centre which placed it
> about a degree away. I printed a chart of this area from Guide and lo - there it was! As
> it is currently mag 13.9 it is a fairly easy target visually as well as for ccd work.
>
> I am using MPCORB database, which I also downloaded and reloaded in Guide last night, so
> I am not sure as to what is causing the discrepancy. The dates are correct in Guide and
> the epoch is 2000. I checked Ceres, just to see if there were any discrepancies of
> position between the ephemeris and Guide, but that one was fine.
>
> Any ideas? Am I missing an update that might cause this behaviour?
>
> I am using XP as I could never overcome the display issues and crashes on my Windows 7
> PC when zooming in further than level 7.
>
> Many thanks for any help
>
> Ian B
>
>
>
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