Re: [guide-user] Crashes when adding asteroids

Denis Jul 6, 2012

Bill,

Can I make a suggestion. At present, I use the alt-j to point
MPCORB_PATH= to the file I wish to use. Why not make a selector for a
MPC file the same way a "TLE" file is selected for display. People would
download from the MPC site the needed files and select the one to
display when needed. This would avoid changing the name in alt-j mode or
renaming the file to "mpcorb.dat"

Denis

On 06/07/2012 11:02 AM, Bill J Gray wrote:
> Hello all,
>
> OK, I've got it figured out... I should have puzzled it out right away;
> in hindsight, the problem is quite obvious to me.
>
> Short version: don't use the links to download critical, unusual, or
> distant objects. Update 'mpcorb.dat' instead. (I'll remove those three
> links in the next update.)
>
> Long version follows:
>
> Once upon a time, all of the "add-on" element lists were small, with at
> most a few hundred objects. But the "distant" list now contains 1717 objects;
> the "unusuals" list contains 9701 objects; and the "critical list" contains
> 1691 objects.
>
> This raises a dilemma. I _could_ just revise Guide to handle this sort
> of thing. But it would be wrong to just bump up the limit. It puts
> thousands of objects into the "added comets/asteroids" file; if you go
> to Extras... Asteroid/Comet Options... Edit Comet/Asteroid Data, you
> get an immense list of objects. And Guide's efforts to merge in these
> MPC update files with existing asteroid data have never been completely
> successful.
>
> To quote from the dialog wherein one can download asteroid data:
>
> "...Use of the following links [to update distant, critical-list,
> and unusual objects] is not really recommended. The objects in question
> already have well-determined orbits, and the latest MPC data will
> represent only a small improvement. By far the best way to update
> asteroids is to use MPCORB. This allows you to update Guide's asteroid
> data completely. The only downside is that MPCORB is about 30 MBytes
> in compressed form, a bit large for those with dial-up modems."
>
> That last issue is getting to be less of a problem; for most of us,
> a 30 MByte download is peanuts. The next update will remove the ability
> to use those three links; we'll go from "updating" asteroids to just
> replacing the entire asteroid dataset with a new MPCORB.DAT.
>
> (Ideally, I'd do the same thing with comets. Sadly, there is no
> way to get a complete comet database; MPC just supplies "currently
> observable comets", which have to be merged with older comets in order
> to have a complete list of comets.)
>
> -- Bill
>
>
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