cdshealpix.nested.cone_search

cdshealpix.nested.cone_search(lon, lat, radius, depth, depth_delta=2, flat=False)

Get the HEALPix cells contained in a cone at a given depth.

This method is wrapped around the cone method from the cdshealpix Rust crate.

Parameters:

lonastropy.coordinates.Longitude

Longitude of the center of the cone.

latastropy.coordinates.Latitude

Latitude of the center of the cone.

radiusastropy.units.Quantity

Radius of the cone.

depthint

Maximum depth of the HEALPix cells that will be returned.

depth_deltaint, optional

To control the approximation, you can choose to perform the computations at a deeper depth using the depth_delta parameter. The depth at which the computations will be made will therefore be equal to depth + depth_delta.

flatboolean, optional

False by default (i.e. returns a consistent MOC). If True, the HEALPix cells returned will all be at depth indicated by depth.

Returns:

ipix, depth, fully_covered(numpy.ndarray, numpy.ndarray, numpy.ndarray)

A tuple containing 3 numpy arrays of identical size:

• ipix stores HEALPix cell indices.

• depth stores HEALPix cell depths.

• fully_covered stores flags on whether the HEALPix cells are fully covered by the cone.

Raises:

ValueError

When one of lat, lon and radius contains more that one value.

Examples

>>> from cdshealpix import cone_search
>>> from astropy.coordinates import Longitude, Latitude
>>> import astropy.units as u
>>> ipix, depth, fully_covered = cone_search(lon=Longitude(0 * u.deg), lat=Latitude(0 * u.deg), radius=10 * u.deg, depth=10)