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Modify fetch_field to allow search around a center with a radius as well #5

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Modify fetch_field to allow search around a center with a radius as well #5

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52 changes: 44 additions & 8 deletions calviacat/panstarrs1.py
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,8 @@
import requests
import numpy as np
from astropy.io import votable
from astropy.coordinates import SkyCoord
import astropy.units as u
from .catalog import Catalog, TableDefinition

# column names and SQLite type
Expand Down Expand Up @@ -90,28 +92,62 @@ def __init__(self, dbfile, phot_type='meanpsfmag', **kwargs):
'ramean', 'decmean', filter2col)
super().__init__(dbfile, ps1, **kwargs)

def fetch_field(self, sources, scale=1.25):
def fetch_field(self, sources, scale=1.25, radius=0.5):
"""Fetch catalog sources for this field and save to database.

Search radius and center are derived from the source list.
Search radius and center are derived from the source list if
len(sources) > 1 or from the first entry and radius if there is only
a single source.

Parameters
----------
sources : SkyCoord
Sources to be matched.
sources : SkyCoord or tuple of (RA center, Dec center) as angle Quantities
or in degrees.
Sources to be matched or center to search around.

scale : float, optional
Search radius scale factor.

radius: float or Quantity, optional, default=0.5
Search radius in degrees or a Quantity that can be transformed
to degrees (`scale` is not applied)
"""
sr = max((sources.separation(c).max() for c in sources)) * scale / 2

if type(sources) == SkyCoord:
try:
sr = max((sources.separation(c).max() for c in sources)) * scale / 2
sr = sr.to(u.deg).value
ra_center = sources.ra.mean().deg
dec_center = sources.dec.mean().deg
except TypeError:
# single center position given
ra_center = sources.ra.deg
dec_center = sources.dec.deg
try:
sr = radius.to(u.deg).value
except AttributeError:
sr = radius
elif type(sources) == tuple:
ra_center = sources[0]
dec_center = sources[1]
try:
ra_center = ra_center.to(u.deg).value
dec_center = dec_center.to(u.deg).value
except AttributeError:
self.logger.debug("Assuming coordinates are in degrees already")
pass
except u.UnitConversionError:
self.logger.error(("Could not convert {} to center coordinates".format(sources)))
try:
sr = radius.to(u.deg).value
except AttributeError:
sr = radius
self.logger.debug(
('Fetching PS1 catalog from STScI over {:.2g} field-of-view.')
('Fetching PS1 catalog from STScI over {:.2g} deg field-of-view.')
.format(sr))

params = dict(RA=sources.ra.mean().deg, DEC=sources.dec.mean().deg,
SR=sr.deg, max_records=self.max_records,
params = dict(RA=ra_center, DEC=dec_center, SR=sr,
max_records=self.max_records,
ordercolumn1='ndetections',
descending1='on',
selectedColumnsCsv=','.join(self.table.columns))
Expand Down