Source code for aiapy.calibrate.meta

Functions for updating/fixing header keywords.
import copy
import warnings

import astropy.time
import astropy.units as u
import numpy as np
from astropy.coordinates import CartesianRepresentation, HeliocentricMeanEcliptic, SkyCoord
from import contains_full_disk

from aiapy.calibrate.util import get_pointing_table
from aiapy.util.exceptions import AiapyUserWarning

__all__ = ["fix_observer_location", "update_pointing"]

[docs] def fix_observer_location(smap): """ Fix inaccurate ``HGS_LON`` and ``HGS_LAT`` FITS keywords. The heliographic Stonyhurst latitude and longitude locations in the AIA FITS headers are incorrect. This function fixes the values of these keywords using the heliocentric aries ecliptic keywords, ``HAEX_OBS, HAEY_OBS, HAEZ_OBS``. .. note:: `` already accounts for the inaccurate HGS keywords by using the HAE keywords to construct the derived observer location. Parameters ---------- smap : `` """ # Create observer coordinate from HAE coordinates coord = SkyCoord( x=smap.meta["haex_obs"] * u.m, y=smap.meta["haey_obs"] * u.m, z=smap.meta["haez_obs"] * u.m, representation_type=CartesianRepresentation, frame=HeliocentricMeanEcliptic,, ).heliographic_stonyhurst # Update header new_meta = copy.deepcopy(smap.meta) new_meta["hgln_obs"] = new_meta["hglt_obs"] = new_meta["dsun_obs"] = return smap._new_instance(, new_meta, plot_settings=smap.plot_settings, mask=smap.mask)
[docs] def update_pointing(smap, *, pointing_table=None): """ Update pointing information in the `smap` header. This function updates the pointing information in `smap` by updating the ``CRPIX1, CRPIX2, CDELT1, CDELT2, CROTA2`` keywords in the header using the information provided in `pointing_table`. If `pointing_table` is not specified, the 3-hour pointing information is queried from the `JSOC <>`_. .. note:: The method removes any ``PCi_j`` matrix keys in the header and updates the ``CROTA2`` keyword. .. note:: If correcting pointing information for a large number of images, it is strongly recommended to query the table once for the appropriate interval and then pass this table in rather than executing repeated queries. Parameters ---------- smap : `` pointing_table : `~astropy.table.QTable`, optional Table of pointing information. If not specified, the table will be retrieved from JSOC. Returns ------- `` See Also -------- aiapy.calibrate.util.get_pointing_table """ # This function can only be applied to full-resolution, full-frame images if not contains_full_disk(smap): raise ValueError("Input must be a full disk image.") shape_full_frame = (4096, 4096) if not all(d == (s * u.pixel) for d, s in zip(smap.dimensions, shape_full_frame)): raise ValueError(f"Input must be at the full resolution of {shape_full_frame}") if pointing_table is None: # Make range wide enough to get closest 3-hour pointing pointing_table = get_pointing_table( - 12 * u.h, + 12 * u.h) # Find row in which T_START <= T_OBS < T_STOP # The following notes are from a private communication with J. Serafin (LMSAL) # and are preserved here to explain the reasoning for selecting the particular # entry from the master pointing table (MPT). # NOTE: The 3 hour MPT entries are computed from limb fits of images with T_OBS # between T_START and T_START + 3hr, so any image with T_OBS equal to # T_START + 3hr - epsilon should still use the 3hr MPT entry for that T_START. # NOTE: For SDO data, T_OBS is preferred to DATE-OBS in the case of the # MPT, using DATE-OBS from near the slot boundary might result in selecting # an incorrect MPT record. t_obs = smap.meta.get("T_OBS") if t_obs is None: warnings.warn( "T_OBS key is missing from metadata. Falling back to " "This may result in selecting in incorrect record from the " "master pointing table.", AiapyUserWarning, stacklevel=3, ) t_obs = t_obs = astropy.time.Time(t_obs) t_obs_in_interval = np.logical_and(t_obs >= pointing_table["T_START"], t_obs < pointing_table["T_STOP"]) if not t_obs_in_interval.any(): raise IndexError( f"No valid entries for {t_obs} in pointing table " f'with first T_START date of {pointing_table[0]["T_START"]} ' f'and a last T_STOP date of {pointing_table[-1]["T_STOP"]}.', ) i_nearest = np.where(t_obs_in_interval)[0][0] w_str = f"{}" new_meta = copy.deepcopy(smap.meta) # Extract new pointing parameters # The x0 and y0 keywords denote the location of the center # of the Sun in CCD pixel coordinates (0-based), but FITS WCS indexing is # 1-based. See Section 2.2 of # x0_mp = pointing_table[f"A_{w_str}_X0"][i_nearest].to("pix").value y0_mp = pointing_table[f"A_{w_str}_Y0"][i_nearest].to("pix").value crpix1 = x0_mp + 1 crpix2 = y0_mp + 1 cdelt = pointing_table[f"A_{w_str}_IMSCALE"][i_nearest].to("arcsecond / pixel").value # CROTA2 is the sum of INSTROT and SAT_ROT. # See # NOTE: Is the value of SAT_ROT in the header accurate? crota2 = pointing_table[f"A_{w_str}_INSTROT"][i_nearest] + smap.meta["SAT_ROT"] * crota2 ="deg").value # Update headers for key, value in [ ("crpix1", crpix1), ("crpix2", crpix2), ("x0_mp", x0_mp), # x0_mp and y0_mp are not standard FITS keywords but they are ("y0_mp", y0_mp), # used when respiking submaps so we update them here. ("cdelt1", cdelt), ("cdelt2", cdelt), ("crota2", crota2), ]: if np.isnan(value): # There are some entries in the pointing table returned from the JSOC that are marked as # MISSING. These get converted to NaNs when we cast it to an astropy quantity table. In # these cases, we just want to skip updating the pointing information. warnings.warn( f"Missing value in pointing table for {key}. This key will not be updated.", AiapyUserWarning, stacklevel=3, ) else: new_meta[key] = value # sunpy map converts crota to a PCi_j matrix, so we remove it to force the # re-conversion. new_meta.pop("PC1_1") new_meta.pop("PC1_2") new_meta.pop("PC2_1") new_meta.pop("PC2_2") return smap._new_instance(, new_meta, plot_settings=smap.plot_settings, mask=smap.mask)