Closed bwgref closed 7 years ago
As per #33 and https://github.com/bwgref/nustar_pysolar/blob/master/notebooks/Sunpy_vs_Skyfield.ipynb, there's a residual 20 arc second offset due to the fact that Astropy's get_sun gives you the apparent coordinates (corrected for aberration) while the NuSTAR coordinates are in astrometric (J2000) coordinates.
Also, the orbital motion of NuSTAR introduces an addition 10-20 arcsecond shift throughout an orbit (as opposed to using a geocentric observer's location, which is what Skyfield does by default).
As per #33 and https://github.com/bwgref/nustar_pysolar/blob/master/notebooks/Sunpy_vs_Skyfield.ipynb, there's a residual 20 arc second offset due to the fact that Astropy's get_sun gives you the apparent coordinates (corrected for aberration) while the NuSTAR coordinates are in astrometric (J2000) coordinates.
Also, the orbital motion of NuSTAR introduces an addition 10-20 arcsecond shift throughout an orbit (as opposed to using a geocentric observer's location, which is what Skyfield does by default).