Re: Comet 39P/Oterma

aje160744 Jun 24, 2013

Mere babe!! - I'm 69 next month and just completed a BSc in Astronomy.


--- In find_orb@yahoogroups.com, Charles Bell <charbell@...> wrote:
>
> Oh, now I got my feeble old eyeballs to see the Xs in both places
>
> I turn 60 this week. There's no holding me back now. 
>
> Thanks again. 
>
>
>
> ________________________________
> From: aje160744 <tony.evans@...>
> To: find_orb@yahoogroups.com
> Sent: Monday, June 24, 2013 11:16 AM
> Subject: [find_orb] Re: Comet 39P/Oterma
>
>
>
>  
> Charles,
>
> I just got the obs for 39P from the MPC and fed them to Find_Orb. It comes up quickly for a solution for the 1958-9 period with the rest of the obs filtered out. Gradually toggle some additional obs "on" and do a full step. Repeat until all the obs are included. Make sure all perturbers are on when doing this. I got to a residual of 0.741" with the worst dozen observations toggled off. That's not bad seeing as many of those old obs are probably a bit shaky. Monte Carlo ran with that solution giving residuals of around 1".
>
> Initially Find_Orb set the epoch at 1959 Mar 29. Orbit a= 3.96, e=0.145. I Changed the epoch to 2013 Jun 24 (+remove worst dozen obs) and the new solution had a residual of 0.743", a=7.37, e=0.235.
>
> Yes, some dramatic changes of orbit!
>
> Tony
>
> --- In find_orb@yahoogroups.com, "cbellh47" <charbell@> wrote:
> >
> > I wanted to investigate the orbit of 39P/Oterma by generating some test particle clones. However, I can't get an orbit solution from the observations in MPCOBS. I know that the object encountered Jupiter in 1963 and shifted its orbit semi major axis from less than a_Jupiter to grater than a_Jupiter. So I tried to get an orbit to calculate using observations from before the encounter and again with observations from after the encounter. I also tried to constrain to known MPC orbit values and orbit epoch values. There are MPC orbits for 7 epochs.
> >
> > I must be missing something.
> >
> > I have no troubles with other objects so far.
> >
> > I give in and ask for help or ideas.
> >
> > Charles
> >
>
>
>
>
> [Non-text portions of this message have been removed]
>