Create a MOC from a filtered astropy Table¶

[1]:

import astropy.units as u
from astropy.visualization.wcsaxes.frame import EllipticalFrame
from astroquery.vizier import Vizier
from mocpy import MOC
import matplotlib.pyplot as plt
from astropy.wcs import WCS

[2]:

viz = Vizier(columns=["*", "_RAJ2000", "_DEJ2000"])
viz.ROW_LIMIT = -1
table = viz.get_catalogs("I/293/npm2cros")[0]

[3]:

galex = MOC.from_fits("../resources/P-GALEXGR6-AIS-FUV.fits")

[4]:

def plot(moc, title=""):
    """Create a plot of a MOC."""
    fig = plt.figure(figsize=(15, 10))

    wcs = WCS(naxis=2)
    wcs.wcs.ctype = ["GLON-AIT", "GLAT-AIT"]
    wcs.wcs.crval = [110.0, 0.0]
    wcs.wcs.cdelt = [-0.675, 0.675]
    wcs.wcs.crpix = [240.5, 120.5]

    ax = fig.add_subplot(1, 1, 1, projection=wcs, frame_class=EllipticalFrame)

    moc.fill(
        ax=ax,
        wcs=wcs,
        edgecolor="r",
        facecolor="r",
        linewidth=1.0,
        fill=True,
        alpha=0.5,
    )
    moc.border(ax=ax, wcs=wcs, color="black", alpha=0.5)

    ax.set_aspect(1.0)

    plt.xlabel("ra")
    plt.ylabel("dec")
    if title:
        plt.title(title)
    plt.grid(color="black", linestyle="dotted")

[9]:

plot(moc=galex, title="P-GALEXGR6-AIS-FUV")

../../_images/_collections_notebooks_filtering_astropy_table_5_0.png

[6]:

table

[7]:

indexes = galex.contains_lonlat(
    table["_RAJ2000"].T * u.deg,
    table["_DEJ2000"].T * u.deg,
)
filtered_table = table[indexes]
filtered_table

[7]:

Table length=10714

_RAJ2000	_DEJ2000	NPM2	KLA	RAJ2000	DEJ2000	ID	IQ	IN	r_Star	mag	tyc
deg	deg									mag
float64	float64	str8	str3	str10	str9	uint8	uint8	uint8	int16	float32	str1
339.638333	83.166667	+83.0016	HPM	22 38 33.2	+83 10 00	1	0	0	811	14.20
339.638333	83.166667	+83.0016	HPM	22 38 33.2	+83 10 00	1	0	0	813	14.20
349.530833	83.010556	+83.0022	VAR	23 18 07.4	+83 00 38	0	0	0	843	--	T
...	...	...	...	...	...	...	...	...	...	...	...
295.010833	-22.548333	-22.2133	HPM	19 40 02.6	-22 32 54	1	0	0	811	14.10
297.006250	-22.252500	-22.2166	CMC	19 48 01.5	-22 15 09	1	0	0	817	10.95	T
297.245417	-22.472778	-22.2169	HPM	19 48 58.9	-22 28 22	1	2	0	811	15.60

[8]:

m1 = MOC.from_lonlat(
    table["_RAJ2000"].T * u.deg,
    table["_DEJ2000"].T * u.deg,
    max_norder=6,
)
m2 = MOC.from_lonlat(
    filtered_table["_RAJ2000"].T * u.deg,
    filtered_table["_DEJ2000"].T * u.deg,
    max_norder=6,
)
plot(moc=m1, title="MOC from table")
plot(moc=m2, title="MOC from filtered table")

../../_images/_collections_notebooks_filtering_astropy_table_8_0.png

../../_images/_collections_notebooks_filtering_astropy_table_8_1.png

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Create a MOC from a filtered astropy Table¶