Hi.
List members interested in computing planetary positions way back into the past or far into the future should have a look at the new ephemeris software package VSOP2013 recently published by G. Francou & J.-L. Simon from the Institut de Mécanique céleste et de calcul des éphémérides (IMCCE). The necessary data files and FORTRAN codes can be downloaded from the IMCCE ftp site ftp://ftp.imcce.fr/pub/ephem/planets/vsop2013/ The ephemerides are made available in two formats: 1) as Chebyshev polynomials valid between -4500 and +4500 ('ephemerides') 2) as an analytical solution based on a time-series development of the classical elliptical elements ('solutions') rvg |
Irv replies:
Their VSOP2013 and TOP2013 paper is forthcoming to be published in Astronomy and Astrophysics: http://www.aanda.org/index.php?option=com_article&access=doi&doi=10.1051/0004-6361/201321843 I'm mainly interested in Earth and Moon, for some reason... Their "solutions" yield the Earth-Moon barycenter, which I suppose is OK for the purposes of calendrical calculations. What is the TOP2013 theory? -- Irv Bromberg, University of Toronto, Canada From: East Carolina University Calendar discussion List [[hidden email]] on behalf of Gent, R.H. van (Rob) [[hidden email]] Sent: Wednesday, July 17, 2013 10:17 List members interested in computing planetary positions way back into the past or far into the future should have a look at the new ephemeris software package VSOP2013 recently published by G. Francou & J.-L. Simon from the Institut de Mécanique céleste et de calcul des éphémérides (IMCCE). The necessary data files and FORTRAN codes can be downloaded from the IMCCE ftp site ftp://ftp.imcce.fr/pub/ephem/planets/vsop2013/ The ephemerides are made available in two formats: 1) as Chebyshev polynomials valid between -4500 and +4500 ('ephemerides') 2) as an analytical solution based on a time-series development of the classical elliptical elements ('solutions') |
In reply to this post by Gent, R.H. van (Rob)
Thanks for posting that. BTW, speaking of planetary positions, did anyone notice that they just discovered a new moon of Neptune by reanalyzing old Hubble imagery?
Victor
On Wed, Jul 17, 2013 at 9:17 AM, Gent, R.H. van (Rob) <[hidden email]> wrote: Hi. |
In reply to this post by Irv Bromberg
Hu Irv, TOP2013, online at
ftp://ftp.imcce.fr/pub/ephem/planets/top2013/ is a similar analytical solution for the outer planets (Jupiter to Neptune) and the dwarf planet Pluto. rvg From: East Carolina University Calendar discussion List [mailto:[hidden email]]
On Behalf Of Irv Bromberg Irv replies: From: East Carolina University Calendar discussion List [[hidden email]] on behalf of Gent, R.H. van (Rob) [[hidden email]] |
Jupiter thru Pluto are included in VSOP2013 -- is the TOP2013 solution more accurate for those planets?
-- Irv From: East Carolina University Calendar discussion List [[hidden email]] on behalf of Gent, R.H. van (Rob) [[hidden email]]
Sent: Wednesday, July 17, 2013 11:50 TOP2013, online at
ftp://ftp.imcce.fr/pub/ephem/planets/top2013/
is a similar analytical solution for the outer planets (Jupiter to Neptune) and the dwarf planet Pluto.
rvg
From: East Carolina University Calendar discussion
List [mailto:[hidden email]] On Behalf Of Irv Bromberg
Irv replies: From: East Carolina University Calendar discussion List [[hidden email]] on behalf of Gent, R.H. van (Rob) [[hidden email]] |
Hi Irv, I do not know – I have not studied the README files close enough.
The forthcoming A&A article – which alerted me to the existence of the VSOP2013 software – will probably give all details. Rob From: East Carolina University Calendar discussion List [mailto:[hidden email]]
On Behalf Of Irv Bromberg Jupiter thru Pluto are included in VSOP2013 -- is the TOP2013 solution more accurate for those planets? From: East Carolina University Calendar discussion List [[hidden email]]
on behalf of Gent, R.H. van (Rob) [[hidden email]] TOP2013, online at
ftp://ftp.imcce.fr/pub/ephem/planets/top2013/ is a similar analytical solution for the outer planets (Jupiter to Neptune) and the dwarf planet Pluto. rvg From: East Carolina University Calendar discussion
List [[hidden email]]
On Behalf Of Irv Bromberg Irv replies: From: East Carolina University Calendar discussion List [[hidden email]] on behalf of Gent, R.H. van (Rob) [[hidden email]] |
In reply to this post by Irv Bromberg
Op 17 jul 2013, om 19:22 heeft Irv Bromberg het volgende geschreven:
> Jupiter thru Pluto are included in VSOP2013 -- is the TOP2013 solution more accurate for those planets? Apparently this is a modernization of the theories VSOP-82 (Bretagnon) and TOP-82 (Simon) from the 1980's. TOP-82 derived expressions only for the giant planets; this appears to be the first to provide analytical expressions for Pluto. VSOP-82 developed the planetary orbits for the variables a,l,k,h,q,p, where the latter four are a complex mix of the usual angular variables e,pi,i,and Omega; the results were later developed into a more traditional Fourier series for the longitude and radius vector. TOP-82 developed the planetary orbits in the usual angular variables. I suppose the same holds for VSOP-2013 and TOP-2013. I never understood the relevance of TOP-82 but apparently it is still worthwhile to re-iterate that path. -- Tom Peters |
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In reply to this post by Gent, R.H. van (Rob)
Hello, I need to calculate the mean longitude (rd) for 2016, 606BC, and 536BC. However, the analytical solution based on a time-series, while it outputs this information nicely, it is only valid for 1890-2000.
I realize the Chebyshev polynomials will do the job as far as the dates are concerned, but it does not output the mean longitude (rd). So does anyone have a simple way of converting the output of Chebyshev polynomials to mean longitude (rd)? Or does anyone have a modified Chebyshev polynomials Fortran code that *will* output the mean longitude (rd)? Thank you, Scott |
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I am aware of the files at http://calndr-l.10958.n7.nabble.com/VSOP2013-New-planetary-ephemerides-valid-from-4500-to-4500-td14002.html
Those are the files I used to discover that I could not get the mean longitude (rd) prior to 1890. If you read my post then you'll see what I am talking about. Thank you, Scott |
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