hmmmmmmm

....i just used the Extras > Asteroid/Comet options > Add MPC Comets/Asteroids > "Click to download updated comet data and addit to Guide" way and printed the comet list.

 

Closed Guide.

 

Then I saved the comet.dat file as stated below, started Guide, and ran a list of comets again, and got a completely different result.

 

So I guess I'll be pulling the most up-to-date comets off the comet.dat file.

 

Thanks again!

-Scott

----- Original Message -----




From: "Bill J Gray" <pluto@...>
To: guide-user@yahoogroups.com
Sent: Monday, November 7, 2011 12:53:46 PM
Subject: Re: [guide-user] up-to-date comet elements

 




Hi Scott,

stripe1966 wrote:
> How do you all get updated comet element? I tried the link found in the
> Extras > Asteroid/Comet options > Add MPC Comets/Asteroids, but the file
> looks exactly the same as it did 2 months ago.

Hmmm... it certainly doesn't change very much, but I do see that today's
version has (P/2011 V1) Boattini, from MPEC 2011-V13, issued on 2 November.

One thing you might do is to just download this file:

http://www.projectpluto.com/comets.dat

...which will bring you completely up to date. (At least, for "right now.")

> And how do you know how recent the file is? Is there a way, in the elements,
> to see the date of the orbital calculation (ie. an epoch date)?

Those wouldn't usually be the same. MPC uses epoch dates at 200-day
intervals, such as JD 2455800.5 = 27 Aug 2011 or JD 2456000.5 = 14 Mar 2012.
But the day on which they compute an orbit can be any day. And the MPC
data won't tell you which.

I do have thoughts for getting around this. As a matter of fact, I had
some insight yesterday as to how to make use of a different source of
comet data (from the IMCCE, roughly the French equivalent of the US Naval
Observatory) to get around the limitations of the MPC data.

-- Bill




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