P. Clay Sherrod Jun 29, 2008
----- Original Message -----
From: "P. Clay Sherrod" <drclay@...>
To: <guide-user@yahoogroups.com>
Sent: Sunday, June 29, 2008 11:46 AM
Subject: Re: [guide-user] Re: Asteroids and Comets
> Bill....
> The problem is in the inherent Guide8 library of asteroids. If you are using Guide8
> to
> find a target, say 7889, with mpcorb.dat loaded, it is pulling the location data from
> the oldest files in the directory file and not from the latest mpcorb files. NOW, if
> you image that field and attempt to determine the astrometric location via CHARON,
> that
> is pulling from the neatod.dat files and the two might be totally different. The only
> solution is to manually EDIT out the older data and use MPC Ephemeris to Add
> Asteroids/Comets on the Extra tool in Guide8.
>
> In other words, Guide8 and Charon and putting the target in two different
> locations....Charon is always right because it is using the latest neatod.dat files,
> but
> Guide8 will always attempt to locate an asteroid by the internal library first. Only
> by
> editing out the old orbital parameters (delete the asteroid manually under EDIT), will
> Guide8 go to the latest mpcorb position. Many times these fields will be off several
> degrees.
>
> I think my question would be: is there a way to completely eliminate the internal
> library of asteroids in Guide8 so that it searches out minor planets using ONLY
> mpcorb.dat files?
> If the directed file is empty, then I would think that Guide would go to the MPC files
> as it does when we manually edit out an object.
>
> This is a pretty big problem in older numbered as well as some year-designation NEOs
> as
> well, even as recent at 2003 or 2004 objects.
>
> Please advise.
>
> Clay
> -------------
> Dr. P. Clay Sherrod
> Arkansas Sky Observatories
> Harvard MPC/ H43 (Conway)
> Harvard MPC/ H41 (Petit Jean Mountain)
> Harvard MPC/ H45 (Petit Jean Mtn. South)
> http://www.arksky.org/
>
>
> ----- Original Message -----
> From: "Bill J Gray" <pluto@...>
> To: <guide-user@yahoogroups.com>
> Sent: Sunday, June 29, 2008 8:04 AM
> Subject: Re: [guide-user] Re: Asteroids and Comets
>
>
>> Hi Dave,
>>
>> Simplest solution to this is to download this file:
>>
>> http://www.projectpluto.com/comets.dat
>>
>> (42473 bytes) and use it to replace the existing
>> 'comets.dat' in your Guide folder.
>>
>> Most people won't run into this issue. But if you've
>> used the 'Add MPC Comets/Asteroids' option to add asteroids,
>> then the headache in question will most definitely arise.
>> You may have downloaded an object known as, say, 2003 XY123,
>> long ago; since then, it's become numbered object (123456)
>> Randomname, listed under that name in the latest 'mpcorb.dat'.
>> Guide has no way to realize that these objects are really one
>> and the same, so it plots them both.
>>
>> The above 'comets.dat' contains only comets, with no
>> asteroids at all, so no chance of doppelgangers.
>>
>> Even more people will run into a related issue: comets are
>> often found under one designation, then given a permanent
>> periodic designation. For example, P/1997 V1 (Larsen) just
>> got the designation Larsen (200P). Unless you go in by hand
>> to remove the first one (or download the above file, in which
>> all such cases are corrected), Guide will show them both.
>>
>> It occurs to me that there's a solution to the asteroid
>> problem: if 'mpcorb.dat' is in use, then MPC comets from
>> 'comets.dat' should be suppressed. (Guide can tell which
>> objects came from MPC and which didn't.) The comet problem
>> is a much hairier one. Ideally, MPC (or someone) would
>> provide a comprehensive comet file, much as it does for
>> asteroids. But it doesn't look as if that's in the works.
>>
>> -- Bill
>>
>> ------------------------------------
>>
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>>
>>
>>
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