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# Source code for astropy.coordinates.builtin_frames.cirs

    # Licensed under a 3-clause BSD style license - see LICENSE.rst

    from astropy.coordinates.attributes import EarthLocationAttribute, TimeAttribute
    from astropy.coordinates.baseframe import base_doc
    from astropy.utils.decorators import format_doc

    from .baseradec import BaseRADecFrame, doc_components
    from .utils import DEFAULT_OBSTIME, EARTH_CENTER

    __all__ = ["CIRS"]

    doc_footer = """
        Other parameters
        ----------------
        obstime : `~astropy.time.Time`
            The time at which the observation is taken.  Used for determining the
            position of the Earth and its precession.
        location : `~astropy.coordinates.EarthLocation`
            The location on the Earth.  This can be specified either as an
            `~astropy.coordinates.EarthLocation` object or as anything that can be
            transformed to an `~astropy.coordinates.ITRS` frame. The default is the
            centre of the Earth.
    """

    @format_doc(base_doc, components=doc_components, footer=doc_footer)
    class CIRS(BaseRADecFrame):
        """
        A coordinate or frame in the Celestial Intermediate Reference System (CIRS).

        The frame attributes are listed under **Other Parameters**.
        """

        obstime = TimeAttribute(
            default=DEFAULT_OBSTIME, doc="The reference time (e.g., time of observation"
        )
        location = EarthLocationAttribute(
            default=EARTH_CENTER, doc="The location on Earth of the observer"
        )

    # The "self-transform" is defined in icrs_cirs_transformations.py, because in
    # the current implementation it goes through ICRS (like GCRS)