Hi Jerome and all, you have linked the same pdf twice. I think you meant the following two links: for the Chebyshev files: ftp://ftp.imcce.fr/pub/ephem/planets/vsop2013/ephemerides/README.pdf and for the elliptic elements: ftp://ftp.imcce.fr/pub/ephem/planets/vsop2013/solution/README.pdf
As Jerome said the elliptic elements are much more interesting because of the possibility to reduce them by truncating the higher order terms. Greetings, Theodor Am 03.10.2015 um 01:46 schrieb JBerthier: > Hi, > > VSOP2013 is the last release of the analytic planetary theory VSOP87. It is > easy to use. You can choose to use theseries of the > elliptic elements > (ftp://ftp.imcce.fr/pub/ephem/planets/vsop2013/ephemerides/README.pdf) or the > Chebyshev files > (ftp://ftp.imcce.fr/pub/ephem/planets/vsop2013/ephemerides/README.pdf). The > solution (terms of series) covers the time span -4000 > +8000, while the Chebyshev ephemerides covers the time span -4500 +4500. The > interest of the solution is that it can be reduced with > the elimination of terms depending on the required accuracy. All the > planetary theories VSOP, INPOP, DExxx are very similar in terms > of planetary ephemerides. > > jerome > > > > On 10/03/2015 12:11 AM, Georg Zotti wrote: >> Dear Theodor, >> >> thank you for the link, I will have a look in the next weeks. >> >> You are right, we are planning to have DE43x as option for advanced users, >> also with the possibility to use the file stored outside Stellarium >> folders (in case you are using it already in other software - no need to >> copy 3GB again ;-). >> >> I haven't read much more than the existence of VSOP2013 or INPOP. Is it as >> easy to use and as complete as VSOP87A and does it cover at least its date >> range, i.e., is it a straightforward exchange? It might be worth thinking >> about using several ephemeris versions... >> >> Kind regards, >> Georg >> >> On Fr, 2.10.2015, 15:20, erazortt wrote: >>> Dear Georg, >>> >>> great to hear that the newest JPL data will be usable! (I assume it will >>> be optional) >>> >>> If you want to cross-check your results using classical computation >>> versus the new IAU computation path I'd be happy if my program would >>> help: http://thaec.rascanu.de/ >>> Installation instructions are included. With a Linux environment it >>> should take less than 5min. >>> >>> As a side: Since the JPL DExxx data sets are not exactly small, I assume >>> most of the stellarium users will probably not use the possibility to >>> load these files, and will thus stick with the VSOP87 calculation you >>> are using. >>> >>> Perhaps it would make sense to update to the VSOP2013 series, which like >>> VSOP87 is very small compared to the numerical JPL data and could be >>> used as default. Thus also enhancing the calculation for the bulk of the >>> users. >>> >>> Greetings, >>> Theodor >>> >>> >>> Am 28.09.2015 um 07:07 schrieb Georg Zotti: >>>> Dear Theodor, >>>> >>>> thank you for your offer, but the DE43[01] challenge has been taken, >>>> there >>>> is a branch "socis2015-de430" on launchpad. Stellarium does not use SOFA >>>> and goes the "classical" path without ERA, so maybe your program would >>>> still interest me as it could be a way to check our results. >>>> >>>> So, is your program available somewhere? (plus, please, instructions how >>>> to build, libraries to fetch etc.) >>>> >>>> Kind regards, >>>> Georg >>>> >>>> On So, 27.09.2015, 22:55, erazortt wrote: >>>>> Hi all, >>>>> >>>>> I have seen that there is a SOC2015 project for using new ephemeris >>>>> files. >>>>> Searching though the mailing list it appeared that there is still >>>>> nobody >>>>> doing this job. >>>>> If however there somebody is already someone doing it, do not bother >>>>> reading the rest. >>>>> >>>>> Although I do not have time to contribute myself directly, perhaps I >>>>> could still help out. >>>>> Some time ago I have written a small C++ program of around 1000 lines >>>>> code which uses the CALCEPH library to either read JPL DE43x or >>>>> INPOP13c >>>>> files. >>>>> It uses the IAU sofa library to calculate the needed time scales in a >>>>> cascade: local time->UTC->TAI->TT->TDB and TCB. >>>>> It downloads the current polar motion and calculates the pole and >>>>> origin >>>>> of GCRS and ITRS together with the ERA (earth rotation angle). >>>>> >>>>> It finally extracts the ephemeris using calceph and calculates the >>>>> positions in all reference frames with sofa, taking into account light >>>>> travel and atmospheric conditions. >>>>> >>>>> The code does also download newest values for UT1-UTC, polar motion and >>>>> corrections to the precession and nutation model from IERS and >>>>> corrections to TT from BIPM. >>>>> It uses exclusively the IAU2000/06 calculation path (opposing to using >>>>> sidereal time, equinox and ecliptic). >>>>> >>>>> If you are interested I can provide the source code. As I said, it is >>>>> very short! >>>>> If needed I could also answer questions related to the sofa and calceph >>>>> libraries or more general questions concerning the time scales or the >>>>> IAU calculation path. >>>>> >>>>> Greetings, >>>>> Theodor >>>>> >>>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> _______________________________________________ >>>> Stellarium-pubdevel mailing list >>>> Stellarium-pubdevel@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/stellarium-pubdevel >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Stellarium-pubdevel mailing list >> Stellarium-pubdevel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/stellarium-pubdevel ------------------------------------------------------------------------------ _______________________________________________ Stellarium-pubdevel mailing list Stellarium-pubdevel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/stellarium-pubdevel
