Merge pull request #7526 from Deus1704/solar_rotate_fix

fixes the `solar_rotate_coordinate()`

changelog/7526.bugfix.rst

@@ -0,0 +1,2 @@
+Added a check in `sunpy.physics.differential_rotation.solar_rotate_coordinate` to ensure the input frame has an "observer" attribute before replicating frame
+attributes, preventing potential issues with frames lacking this attribute.

sunpy/physics/differential_rotation.py

@@ -255,8 +255,12 @@ def solar_rotate_coordinate(coordinate, observer=None, time=None, **diff_rot_kwa
     # Calculate where the rotated coordinate appears as seen by new observer
     # for the coordinate system of the input coordinate.  The translational
     # motion of the Sun will be ignored for the transformation.
-    frame_newobs = coordinate.frame.replicate_without_data(observer=new_observer,
+
+    if "observer" in coordinate.frame.frame_attributes.keys():
+        frame_newobs = coordinate.frame.replicate_without_data(observer=new_observer,
                                                            obstime=new_observer.obstime)
+    else:
+        frame_newobs = coordinate.frame.replicate_without_data(obstime=new_observer.obstime)
     with transform_with_sun_center():
         return heliographic_rotated.transform_to(frame_newobs)
 

sunpy/physics/tests/test_differential_rotation.py

@@ -5,7 +5,7 @@
 import astropy.units as u
 from astropy.coordinates import SkyCoord
 from astropy.tests.helper import assert_quantity_allclose
-from astropy.time import TimeDelta
+from astropy.time import Time, TimeDelta
 
 import sunpy.map
 from sunpy.coordinates import frames, transform_with_sun_center
@@ -132,6 +132,16 @@ def test_solar_rotate_coordinate():
         # Test that the SkyCoordinate is Helioprojective
         assert isinstance(d.frame, frames.Helioprojective)
 
+    # Test that the function works correctly with a HGS coordinate.
+    earth_coord = get_earth(Time("2022-03-30"))
+    coord_hpc = SkyCoord(100*u.arcsec, 100*u.arcsec, frame=frames.Helioprojective(observer=earth_coord))
+
+    coord_hgs = coord_hpc.transform_to(frames.HeliographicStonyhurst)
+    with pytest.warns(UserWarning, match="Using 'time' assumes an Earth-based observer"):
+        rotated_coord_hgs = solar_rotate_coordinate(coord_hgs, time=Time("2022-03-31"))
+
+    assert isinstance(rotated_coord_hgs.frame, frames.HeliographicStonyhurst)
+
 
 def test_consistency_with_rotatedsunframe():
     old_observer = frames.HeliographicStonyhurst(10*u.deg, 20*u.deg, 1*u.AU, obstime='2001-01-01')