Move find_apass_stars to core

stellarphot/core.py

@@ -5,6 +5,7 @@
 from astropy.table import Column, QTable, Table
 from astropy.time import Time
 from astropy.units import Quantity
+from astropy.wcs import WCS
 
 from astroquery.vizier import Vizier
 
@@ -386,7 +387,7 @@ def clean(self, remove_rows_with_mask=False, **other_restrictions):
             comparison_func = comparisons[results.group(1)]
             comparison_value = results.group(2)
             new_keepers = comparison_func(self[column],
-                                        float(comparison_value))
+                                         float(comparison_value))
             keepers = keepers & new_keepers
 
         return self[keepers]
@@ -867,7 +868,7 @@ def _tidy_vizier_catalog(data, mag_column_regex, color_column_regex):
                            passband in zip(mag_err_cols, passbands)}
 
         # All columns except those we have renamed should be preserved, so make
-        # a list of them for us in wide_to_long.
+        # a list of them for use in wide_to_long.
         id_columns = set(data.colnames) - set(orig_cols) - set(mag_err_cols)
 
         # Make the input data into a Pandas DataFrame
@@ -976,7 +977,7 @@ def from_vizier(cls,
         else:
             # Find the center of the frame
             shape = (header_or_center['NAXIS2'], header_or_center['NAXIS1'])
-            center = header_or_center.wcs.pixel_to_world(shape[1] / 2,
+            center = WCS(header_or_center).pixel_to_world(shape[1] / 2,
                                                          shape[0] / 2)
 
         # Get catalog via cone search
@@ -1012,7 +1013,7 @@ def from_vizier(cls,
         # desired.
         if clip_by_frame:
             cat_coords = SkyCoord(ra=cat['ra'], dec=cat['dec'])
-            x, y = header_or_center.wcs.all_world2pix(cat_coords.ra, cat_coords.dec, 0)
+            x, y = WCS(header_or_center).all_world2pix(cat_coords.ra, cat_coords.dec, 0)
             in_x = (x >= padding) & (x <= header_or_center.wcs.pixel_shape[0] - padding)
             in_y = (y >= padding) & (y <= header_or_center.wcs.pixel_shape[1] - padding)
             in_fov = in_x & in_y
@@ -1021,6 +1022,47 @@ def from_vizier(cls,
         return cat
 
 
+def apass_dr9(header_or_center,
+              radius=1 * u.degree,
+              clip_by_frame=False,
+              padding=100):
+    """
+    Return the items from APASS DR9 that are within the search radius and
+    (optionally) within the field of view of a frame.
+
+    Parameters
+    ----------
+    header_or_center : FITS header or `astropy.coordinates.SkyCoord`
+        Either a FITS header with WCS information or a `SkyCoord` object.
+        The center of the frame or the input coordinate is the center
+        of the cone search.
+
+    radius : `astropy.units.Quantity`, optional
+        Radius around which to search.
+
+    clip_by_frame : bool, optional
+        If ``True``, only return items that are within the field of view
+        of the frame. Default is ``True``.
+
+    padding : int, optional
+        Coordinates need to be at least this many pixels in from the edge
+        of the frame to be considered in the field of view. Default value
+        is 100.
+
+    """
+    apass_colnames = {
+        'recno': 'id', # There is no APASS ID, this is the one generated by Vizier
+        'RAJ2000': 'ra',
+        'DEJ2000': 'dec',
+    }
+    return CatalogData.from_vizier(header_or_center,
+                                   'II/336/apass9',
+                                   radius=radius,
+                                   clip_by_frame=clip_by_frame,
+                                   padding=padding,
+                                   colname_map=apass_colnames)
+
+
 class SourceListData(BaseEnhancedTable):
     """
     A class to hold information on the source lists to pass to

stellarphot/tests/test_core.py

@@ -3,13 +3,15 @@
 from astropy import units as u
 from astropy.table import Table, Column
 from astropy.time import Time
-from astropy.io import ascii
+from astropy.io import ascii, fits
 from astropy.coordinates import EarthLocation, SkyCoord
+from astropy.nddata import CCDData
 from astropy.utils.data import get_pkg_data_filename
+from astropy.wcs import WCS
 from pydantic import ValidationError
 
 from stellarphot.core import (Camera, BaseEnhancedTable, PhotometryData,
-                              CatalogData, SourceListData)
+                              CatalogData, SourceListData, apass_dr9)
 
 
 def test_camera_attributes():
@@ -567,6 +569,32 @@ def prepare_cat(cat):
     assert my_cat['Type'][0] == 'SRB'
 
 
+def test_find_apass():
+    CCD_SHAPE = [2048, 3073]
+    # This is really checking from APASS DR9 on Vizier, or at least that
+    # is where the "expected" data is drawn from.
+    expected_all = Table.read(get_pkg_data_filename('data/all_apass_ey_uma_sorted_ra_first_20.fits'))
+
+    wcs_file = get_pkg_data_filename('data/sample_wcs_ey_uma.fits')
+    wcs = WCS(fits.open(wcs_file)[0].header)
+    wcs.pixel_shape = list(reversed(CCD_SHAPE))
+    ccd = CCDData(data=np.zeros(CCD_SHAPE), wcs=wcs, unit='adu')
+
+    # Turn this into an HDU to get the standard FITS image keywords
+    ccd_im = ccd.to_hdu()
+    all_apass = apass_dr9(ccd_im[0].header, radius=1 * u.deg)
+
+    # Reference data was sorted by RA, first 20 entries kept
+    # There are 6 magnitude or color columns, so 6 * 20 = 120 rows
+    # in the resulting table.
+    all_apass.sort('ra')
+    all_apass = all_apass[:120]
+
+    # It is hard to imagine the RAs matching and other entries not matching,
+    # so just check the RAs.
+    assert set(ra.value for ra in all_apass['ra']) == set(expected_all['RAJ2000'])
+
+
 # Load test apertures
 test_sl_data = ascii.read(get_pkg_data_filename('data/test_sourcelist.ecsv'),
                              format='ecsv',

stellarphot/utils/tests/test_catalog_search.py

@@ -109,25 +109,3 @@ def test_catalog_search_with_coord_and_frame_clip_fails():
         _ = catalog_search(cen_coord, [4096, 4096], 'B/vsx/vsx',
                            clip_by_frame=True)
     assert 'To clip entries by frame' in str(e.value)
-
-
-def test_find_apass():
-    # This is really checking from APASS DR9 on Vizier, or at least that
-    # is where the "expected" data is drawn from.
-    expected_all = Table.read(get_pkg_data_filename('data/all_apass_ey_uma_sorted_ra_first_20.fits'))
-    expected_low_error = Table.read(get_pkg_data_filename('data/low_error_apass_ey_uma_sorted_ra_first_20.fits'))
-    wcs_file = get_pkg_data_filename('data/sample_wcs_ey_uma.fits')
-    wcs = WCS(fits.open(wcs_file)[0].header)
-    wcs.pixel_shape = list(reversed(CCD_SHAPE))
-    ccd = CCDData(data=np.zeros(CCD_SHAPE), wcs=wcs, unit='adu')
-    all_apass, apass_low_error = find_apass_stars(ccd)
-    # print(all_apass)
-    # REference data was sorted by RA, first 20 entries kept
-    all_apass.sort('RAJ2000')
-    all_apass = all_apass[:20]
-    apass_low_error.sort('RAJ2000')
-    apass_low_error = apass_low_error[:20]
-    # It is hard to imagine the RAs matching and other entries not matching,
-    # so just check the RAs.
-    assert all(all_apass['RAJ2000'] == expected_all['RAJ2000'])
-    assert all(apass_low_error['RAJ2000'] == expected_low_error['RAJ2000'])