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
