punchbowl.data.wcs#
Attributes#
Classes#
A WCS that accepts and returns GCRS SkyCoords. |
Functions#
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Extract CROTA from a WCS. |
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Calculate the helio WCS from a celestial WCS. |
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Get the position of the Sun in right ascension and declination. |
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Calculate a PC matrix given CROTA and CDELT. |
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Get the P angle. |
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Convert helioprojective to GCRS. |
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Calculate the celestial WCS from a helio WCS. |
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Project vec1 onto the plane perpendicular to vec2. |
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Compute the angle between vec1 and vec2. |
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Compute the necessary rotation angle to align a celestial WCS to a helioprojective one. |
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Load Level 2 trefoil world coordinate system and shape. |
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Load Level quickPUNCH mosaic world coordinate system and shape. |
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Load Level quickPUNCH NFI world coordinate system and shape. |
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Compute the angle of celestial north direction at each pixel using the WCS. |
Module Contents#
- punchbowl.data.wcs._ROOT = b'.'#
- punchbowl.data.wcs.PUNCH_STOKES_MAPPING#
- punchbowl.data.wcs.extract_crota_from_wcs(wcs: astropy.wcs.WCS) astropy.units.deg[source]#
Extract CROTA from a WCS.
- punchbowl.data.wcs.calculate_helio_wcs_from_celestial(wcs_celestial: astropy.wcs.WCS, date_obs: astropy.time.Time | str | None = None, data_shape: tuple[int, int] | None = None) astropy.wcs.WCS[source]#
Calculate the helio WCS from a celestial WCS.
- punchbowl.data.wcs.get_sun_ra_dec(dt: datetime.datetime) tuple[float, float][source]#
Get the position of the Sun in right ascension and declination.
- punchbowl.data.wcs.calculate_pc_matrix(crota: float, cdelt: tuple[float, float]) numpy.ndarray[source]#
Calculate a PC matrix given CROTA and CDELT.
- Parameters:
crota (float) – rotation angle from the WCS
cdelt (float) – pixel size from the WCS
- Returns:
PC matrix
- Return type:
np.ndarray
- punchbowl.data.wcs._times_are_equal(time_1: astropy.time.Time, time_2: astropy.time.Time) bool[source]#
- punchbowl.data.wcs.get_p_angle(time: str = 'now') astropy.units.deg[source]#
Get the P angle.
Return the position (P) angle for the Sun at a specified time, which is the angle between geocentric north and solar north as seen from Earth, measured eastward from geocentric north. The range of P is +/-26.3 degrees.
- Parameters:
time ({parse_time_types}) – Time to use in a parse_time-compatible format
- Returns:
out – The position angle
- Return type:
~astropy.coordinates.Angle
- punchbowl.data.wcs.calculate_celestial_wcs_from_helio(wcs_helio: astropy.wcs.WCS, date_obs: astropy.time.Time | str | None = None, data_shape: tuple[int, int] | None = None) astropy.wcs.WCS[source]#
Calculate the celestial WCS from a helio WCS.
- punchbowl.data.wcs.project_vec_onto_plane(vec1: numpy.ndarray, vec2: numpy.ndarray) numpy.ndarray[source]#
Project vec1 onto the plane perpendicular to vec2.
- punchbowl.data.wcs.angle_between_vectors(vec1: numpy.ndarray, vec2: numpy.ndarray, plane_normal: numpy.ndarray) numpy.ndarray[source]#
Compute the angle between vec1 and vec2.
The angle is computed in the plane normal to plane_normal. This normal vector also sets the handedness and the sign of the angle.
- punchbowl.data.wcs.compute_hp_to_eq_rotation_angle(wcs_helio: astropy.wcs.WCS, date_obs: str | astropy.time.Time | None = None) astropy.units.Quantity[source]#
Compute the necessary rotation angle to align a celestial WCS to a helioprojective one.
The computed angle includes the effect of the P angle but not the rotation of the helioprojective WCS
- Parameters:
wcs_helio (WCS) – A helioprojective WCS for which we’re producing a corresponding celestial WCS. Only CRVAL is used from this WCS
date_obs (str | Time | None) – The observation date. If not provided, it will be pulled from wcs_helio. If not provided in wcs_helio, it must be specified here.
- Returns:
rotation_angle – The rotation angle that should be added to that in wcs_celestial’s PC matrix
- Return type:
Quantity
- punchbowl.data.wcs.load_trefoil_wcs() tuple[astropy.wcs.WCS, tuple[int, int]][source]#
Load Level 2 trefoil world coordinate system and shape.
- punchbowl.data.wcs.load_quickpunch_mosaic_wcs() tuple[astropy.wcs.WCS, tuple[int, int]][source]#
Load Level quickPUNCH mosaic world coordinate system and shape.
- punchbowl.data.wcs.load_quickpunch_nfi_wcs() tuple[astropy.wcs.WCS, tuple[int, int]][source]#
Load Level quickPUNCH NFI world coordinate system and shape.
- punchbowl.data.wcs.celestial_north_from_wcs(input_wcs: astropy.wcs.WCS, shape: tuple, eps: astropy.units.Quantity = 1.0 * u.arcsec) numpy.ndarray[source]#
Compute the angle of celestial north direction at each pixel using the WCS.
- Parameters:
input_wcs (astropy.wcs.WCS) – 2D celestial WCS (e.g., RA/Dec TAN) or a WCS where the celestial axes are the first two. If WCS has extra axes (e.g., STOKES), pass a dropped/sliced 2D WCS (e.g., wcs.dropaxis(2)).
shape (tuple) – Shape of the image as (nrows, ncols).
eps (astropy.units.Quantity) – Small sky offset applied toward celestial north (positive Dec direction) to estimate the local north direction.
- Returns:
angle_cel_north – Angle in degrees from +Y image axis to celestial north at each pixel (measured counterclockwise in the pixel coordinate system):
angle = atan2(dx, dy)
- Return type:
2D numpy.ndarray
- class punchbowl.data.wcs.GCRSWCS(*args: tuple, meta: punchbowl.data.NormalizedMetadata, **kwargs: dict)[source]#
Bases:
astropy.wcs.WCSA WCS that accepts and returns GCRS SkyCoords.
This is necessary because there doesn’t seem to be a native way to tell a WCS it is GCRS. I think we could register a definition with Astropy that if the FITS RADESYS key is set to ‘gcrs’ it should use GCRS SkyCoords, but the velocity information in the header doesn’t appear to be read into the WCS object, and at the point where we’re registering this with Astropy, we only have access to the WCS object, not the original header.
- _meta#
- _gcrs_frame#
- _get_components_and_classes() tuple[source]#
Determine the coordinate frame for a SkyCoord.
When creating a SkyCoord, this is the method WCS objects use to select a coordinate frame. Rather than registering something within the default implementation, we override and replace the coordinate frame with our GCRS frame.