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EOP in Python (Precession Nutation) #6680
Description
Hi,
I am looking for a way to query the IERS bulletin and obtain the Earth Orientation Parameters in Python. The analogue of the IDL hprstatn.pro procedure.
Just checking if this is implemented in some form in Astropy. I know that I can query the IERS bulletin and obtain the table, but is the final product already done?
My end goal is to obtain the x,y,z,vx,vy,vz of an observatory wrt the barycenter taking into consideration these movements.
Activity
StuartLittlefair commentedon Oct 9, 2017
Hi @shbhuk
EarthLocation.get_gcrs_posveldoes do (almost) what you require. The only thing not in there is IERS corrections to precession/nutation (dX_2000A,dY_2000Ain the IERS tables). Comparison to PINT reveals that these make a difference at the 2m and 1/100th of a cm/s level, which shouldn't be an issue for most people.HOWEVER, I've found a bug in that routine (#6697) which limits the accuracy to the m/s level. I'll issue a PR for that bug soon.
shbhuk commentedon Oct 9, 2017
On comparison of the PINT routine and
EarthLocation.get_gcrs_posvelwe are observing a difference of about 0.5-0.6 m/s . We would ideally like of the order of mm/s. I shall try the fix that you have applied once it is included.