class RectangleSkySlit(_RectangleSlitBase):
"""
Slit constructed using WCS and coords information.
Utilizes `regions` package.
Parameters
----------
wcs : `astropy.wcs.WCS`
ra, dec : float
Center (ra, dec) of slit in deg.
width, length : float
Angular width and length of slit in arcsec.
"""
def __init__(self, wcs, ra, dec, width, length, *args, **kwargs):
self.wcs = wcs
skycoord = SkyCoord(ra,
dec,
unit=(u.Unit(u.deg), u.Unit(u.deg)),
frame='fk5')
length = Angle(length, u.arcsec)
width = Angle(width, u.arcsec)
self._sky_region = RectangleSkyRegion(center=skycoord,
width=width,
height=length)
# N.B: The following step will not be needed when
# regions.RectangleSkyRegion.as_artist is implemented
self._pix_region = self._sky_region.to_pixel(wcs)
self._patch = self._pix_region.as_artist(edgecolor='red',
facecolor='none')
self._is_active = False
class RectangleSkySlit(_RectangleSlitBase):
"""
Slit constructed using WCS and coords information.
Utilizes `regions` package.
Parameters
----------
wcs : `astropy.wcs.WCS`
ra, dec : float
Center (ra, dec) of slit in deg.
width, length : float
Angular width and length of slit in arcsec.
"""
def __init__(self, wcs, ra, dec, width, length, *args, **kwargs):
self.wcs = wcs
skycoord = SkyCoord(ra, dec,
unit=(u.Unit(u.deg),
u.Unit(u.deg)),
frame='fk5')
length = Angle(length, u.arcsec)
width = Angle(width, u.arcsec)
self._sky_region = RectangleSkyRegion(center=skycoord, width=width, height=length)
# N.B: The following step will not be needed when
# regions.RectangleSkyRegion.as_artist is implemented
self._pix_region = self._sky_region.to_pixel(wcs)
self._patch = self._pix_region.as_artist(edgecolor='red', facecolor='none')
self._is_active = False
on_ellipse_annulus = EllipseAnnulusSkyRegion(
center=position,
inner_width=1.5 * u.deg,
outer_width=2.5 * u.deg,
inner_height=3 * u.deg,
outer_height=4 * u.deg,
angle=130 * u.deg,
)
another_position = SkyCoord(80.3, 22.0, unit="deg")
on_rectangle = RectangleSkyRegion(center=another_position,
width=2.0 * u.deg,
height=4.0 * u.deg,
angle=50 * u.deg)
# Now we plot those regions. We first create an empty map
empty_map = WcsNDMap.create(skydir=position,
width=10 * u.deg,
binsz=0.1 * u.deg,
proj="TAN")
empty_map.data += 1.0
empty_map.plot(cmap="gray", vmin=0, vmax=1)
# To plot the regions, we convert them to PixelRegion with the map wcs
on_circle.to_pixel(empty_map.geom.wcs).plot()
on_rectangle.to_pixel(empty_map.geom.wcs).plot()
on_ellipse_annulus.to_pixel(empty_map.geom.wcs).plot()
plt.show()
# The ON region center is defined in the icrs frame. The angle is defined w.r.t. to its axis.
rectangle = RectangleSkyRegion(center=crab_position,
width=0.5 * u.deg,
height=0.4 * u.deg,
angle=0 * u.deg)
bkg_maker = ReflectedRegionsBackgroundMaker(min_distance=0.1 * u.rad)
dataset_maker = SpectrumDatasetMaker(selection=["counts"])
e_reco = MapAxis.from_energy_bounds(0.1, 100, 30, unit="TeV")
dataset_empty = SpectrumDataset.create(e_reco=e_reco, region=rectangle)
datasets = []
for obs in observations:
dataset = dataset_maker.run(dataset_empty.copy(name=f"obs-{obs.obs_id}"),
obs)
dataset_on_off = bkg_maker.run(observation=obs, dataset=dataset)
datasets.append(dataset_on_off)
m = Map.create(skydir=crab_position, width=(8, 8), proj="TAN")
_, ax, _ = m.plot(vmin=-1, vmax=0)
rectangle.to_pixel(ax.wcs).plot(ax=ax, color="black")
plot_spectrum_datasets_off_regions(datasets=datasets, ax=ax)
plt.show()