Python in Astronomy¶

Pandas¶

何勃亮 中国科学院国家天文台国家天文科学数据中心

%matplotlib inline

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

data = pd.read_csv('data/dr1.sample', delimiter='|')

data.head()

data[['ra','dec']]

from astropy import units as u

from astropy.coordinates import Angle

fig = plt.figure()

axes = fig.add_axes([0.1, 0.1, 0.8, 0.8]) # left, bottom, width, height (range 0 to 1)

axes.scatter(data['ra'], data['dec'], s = data['mag2'])

xticks = axes.get_xticks()
yticks = axes.get_yticks()

xt = ["$%.1f^{\circ}$"%n for n in xticks.tolist()]
yt = ["$%.1f^{\circ}$"%n for n in yticks.tolist()]

xt,yt
axes.set_xticklabels(xt)
axes.set_yticklabels(yt)

[<matplotlib.text.Text at 0x10d447198>,
 <matplotlib.text.Text at 0x10d44bc50>,
 <matplotlib.text.Text at 0x10d472a20>,
 <matplotlib.text.Text at 0x10d455048>,
 <matplotlib.text.Text at 0x10d4474a8>,
 <matplotlib.text.Text at 0x10d43dcc0>,
 <matplotlib.text.Text at 0x10d4ac748>,
 <matplotlib.text.Text at 0x10d4b20f0>,
 <matplotlib.text.Text at 0x10d4b2b00>]

	obsid	designation	obsdate	lmjd	planid	spid	fiberid	ra	dec	snru	...	mag5	mag6	mag7	tsource	fibertype	tfrom	t_info	rv	z	z_err
0	101001	J220848.54-020324.3	2011-10-24	55859	F5902	1	1	332.202274	-2.056767	2.23	...	15.97	99.0	99.0	JF_LEGAS_S	Obj	SDSS_S	NaN	-23.069030	NaN	0.000003
1	101002	J220953.17-020506.0	2011-10-24	55859	F5902	1	2	332.471576	-2.085015	2.00	...	15.67	99.0	99.0	JF_LEGAS_S	Obj	SDSS_S	NaN	27.100000	NaN	0.000178
2	101008	J220928.49-015720.7	2011-10-24	55859	F5902	1	8	332.368745	-1.955771	1.84	...	15.64	99.0	99.0	JF_LEGAS_S	Obj	SDSS_S	NaN	25.038666	NaN	0.000003
3	101009	J220849.59-015207.1	2011-10-24	55859	F5902	1	9	332.206665	-1.868653	1.86	...	16.25	99.0	99.0	JF_LEGAS_S	Obj	SDSS_S	NaN	-22.169652	NaN	0.000005
4	101016	J220923.69-020809.9	2011-10-24	55859	F5902	1	16	332.348725	-2.136096	2.17	...	14.62	99.0	99.0	JF_LEGAS_S	Obj	SDSS_S	NaN	-6.631409	NaN	0.000001

	ra	dec
0	332.202274	-2.056767
1	332.471576	-2.085015
2	332.368745	-1.955771
3	332.206665	-1.868653
4	332.348725	-2.136096
...	...	...
994	332.904375	0.369077
995	332.857210	0.272130
996	332.891050	0.215370
997	333.020110	0.150630
998	333.113113	0.108325