OK experiment, try this:
1) download the two files, NEA and NEAm00 from MPC and rename them both mpcorb.dat, (of course keep them separeted in two different directories)
2) put one of them in Guide,
3) choose one asteroid, let us say 2010 FL48, but enyone else is fine, if it is fast is better,
4) show the asteroid on Guide,
5) keep note of the time and AR and Dec,
6) substitute the first mpcorb.dat file with the second,
7) set the same time as recorded at point 5 and check the coordinates for the same asteroid you choosen at point 3,
8) compare the two mesures as point 5 and point 7 of AR and Dec, are they the same?
Best regards, Stefano

--- In guide-user@yahoogroups.com, "P. Clay Sherrod" <drclay@...> wrote:
>
> I use the database every night and other than small residuals which should be expected,
> the targets are very much where they "should be". I am not sure why you would be seeing
> any offset unless the TIME on your computer or telescope is set incorrectly....I have
> noted that Guide is once again "losing an hour" compared to true GMT because of the DST
> time change. I had to change one observatory computer TIMEOFFSET = 1 and then reboot to
> have the correct GMT...that very likely could be the source of the offset.
>
> 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: "Stefano TREVISAN" <trvsfn@...>
> To: <guide-user@yahoogroups.com>
> Sent: Tuesday, March 30, 2010 11:44 AM
> Subject: [guide-user] Re: NEAs or NEAs today?
>
>
> > OK, sorry, please read NEAm00 instaed of NEAtod in all my previous messages, I keep
> > using the old name but I mean NEAm00.
> >
> > Stefano
> >
> > --- In guide-user@yahoogroups.com, "P. Clay Sherrod" <drclay@> wrote:
> >>
> >> Where are you getting NEAtod datasets? MPC is no longer putting out that file. It is
> >> now
> >> only NEAm00. If you are picking up NEAtod.dat files from a mirror site, that is very
> >> likely outdated. (probably from Feb. 12 when MPC computers were hacked).
> >>
> >> 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: "Stefano TREVISAN" <trvsfn@>
> >> To: <guide-user@yahoogroups.com>
> >> Sent: Tuesday, March 30, 2010 7:02 AM
> >> Subject: [guide-user] Re: NEAs or NEAs today?
> >>
> >>
> >> > Hi Dr. Clay,
> >> > that is what I knew and what I do.
> >> > Nevertheless I still don't fully understand why I get different results using the NEA
> >> > and the NEAtod datasets.
> >> > Many thanks for your replay.
> >> > Stefano
> >> >
> >> > --- In guide-user@yahoogroups.com, "P. Clay Sherrod" <drclay@> wrote:
> >> >>
> >> >> Hello Stefano....
> >> >> You will want to load "NEA Today" (NEAm00):
> >> >> http://www.minorplanetcenter.org/iau/MPCORB/NEAm00.txt
> >> >> and then change the file name AND extension (.dat) to the
> >> >> mpcorb.dat and neatod.dat names.
> >> >>
> >> >> Having both datasets (identical except for different names) in Guide will allow the
> >> >> same
> >> >> dataset to match in both Guide and Charon.
> >> >>
> >> >> 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: "Stefano TREVISAN" <trvsfn@>
> >> >> To: <guide-user@yahoogroups.com>
> >> >> Sent: Tuesday, March 30, 2010 5:28 AM
> >> >> Subject: [guide-user] NEAs or NEAs today?
> >> >>
> >> >>
> >> >> > Hi all,
> >> >> > I downloaded the two files from the MPC mirror, saved both as mpcorb.dat and I
> >> >> > used
> >> >> > them
> >> >> > on Guide.
> >> >> > Same asteroid, same time, same...all but the positions shown on Guide are slightly
> >> >> > different.
> >> >> > I know I have to use NEAtod.dat but I do not understand the difference between the
> >> >> > two
> >> >> > datasets, or better, I don't understand why two different results.
> >> >> > Probably this issue was already discussed in this forum in the past but I didn't
> >> >> > find
> >> >> > it, sorry.
> >> >> > Any help is really appreciated.
> >> >> > Best regards
> >> >> > Stefano TREVISAN
> >> >> > B38
> >> >> >
> >> >> >
> >> >> >
> >> >> > ------------------------------------
> >> >> >
> >> >> > To unsubscribe from this group, send an empty email to:
> >> >> > guide-user-unsubscribe@! Groups Links
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >>
> >> >
> >> >
> >> >
> >> >
> >> > ------------------------------------
> >> >
> >> > To unsubscribe from this group, send an empty email to:
> >> > guide-user-unsubscribe@! Groups Links
> >> >
> >> >
> >> >
> >> >
> >> >
> >>
> >
> >
> >
> >
> > ------------------------------------
> >
> > To unsubscribe from this group, send an empty email to:
> > guide-user-unsubscribe@...! Groups Links
> >
> >
> >
> >
>