“Astropy”的版本间差异
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| （未显示同一用户的26个中间版本） | |||
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*很好的教程网站 [https://learn.astropy.org/] |
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:比如星际红化的 [https://learn.astropy.org/tutorials/color-excess.html] |
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==io== |
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>>> hdulist = fits.open('input.fits') |
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>>> hdulist.info() |
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* ascii文件：Table格式，支持ecsv文件直接读入table |
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==astrometry== |
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*each element of an HDUList is an HDU object with .header and .data attributes, which can be used to access the header and data portions of the HDU. |
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*match 两个星表 |
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>>> hdulist[0].header['targname'] |
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>>> from astropy.coordinates import SkyCoord |
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>>> from astropy import units as u |
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>>> c = SkyCoord(ra=ra1*u.degree, dec=dec1*u.degree) |
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>>> catalog = SkyCoord(ra=ra2*u.degree, dec=dec2*u.degree) |
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>>> idx, d2d, d3d = c.match_to_catalog_sky(catalog) #d3d是假设距离为1的地方的3维距离，因此是以弧度为单位 |
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>>> sel=np.where(d2d.degree < 0.00002) |
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>>> Nsel=len(sel[0]) |
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>>> print(ra1[sel][0],ra2[idx[sel][0]) |
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*算出任意两点之间距离向量的PA角，还有中点坐标[https://docs.astropy.org/en/stable/coordinates/matchsep.html] |
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==宇宙学== |
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*To see the entire header as it appears in the FITS file (with the END card and padding stripped), simply enter the header object by itself, or print(repr(header)): |
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http://docs.astropy.org/en/stable/cosmology/ |
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*It’s also possible to view a slice of the header: |
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*从红移到年龄 |
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>>> header[:2] |
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>>>from astropy.cosmology import FlatLambdaCDM |
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*Another way to either update an existing card or append a new one is to use the Header.set() method: |
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>>>cosmo = FlatLambdaCDM(H0=70, Om0=0.3) |
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>>> prihdr.set('observer', 'Edwin Hubble') |
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>>> lum_dis=cosmo.luminosity_distance(redshift) #计算光度距离 |
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*从年龄到红移 |
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>>> import astropy.units as u |
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>>> from astropy.cosmology import z_at_value |
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>>> z_at_value(cosmos.age, 2 * u.Gyr) |
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==单位转换== |
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dL=lum_dis.to(u.cm) |
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==bug== |
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*在anaconda3.8.3升级 astropy 和liberfc之后，astropy.fits出错，解决方法是降级 |
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*安装pytorch之后，自动降级到4.3，但是还是又小问题 |
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*进一步[[conda]]指定降级到4.2才行 |
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*可以看出[[conda]]的版本管理并不好, |
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2024年7月12日 (五) 14:24的最新版本
- 很好的教程网站 [1]
- 比如星际红化的 [2]
io
- astropy.io.fits
- ascii文件：Table格式，支持ecsv文件直接读入table
astrometry
- match 两个星表
>>> from astropy.coordinates import SkyCoord >>> from astropy import units as u >>> c = SkyCoord(ra=ra1*u.degree, dec=dec1*u.degree) >>> catalog = SkyCoord(ra=ra2*u.degree, dec=dec2*u.degree) >>> idx, d2d, d3d = c.match_to_catalog_sky(catalog) #d3d是假设距离为1的地方的3维距离，因此是以弧度为单位 >>> sel=np.where(d2d.degree < 0.00002) >>> Nsel=len(sel[0]) >>> print(ra1[sel][0],ra2[idx[sel][0])
- 算出任意两点之间距离向量的PA角，还有中点坐标[3]
宇宙学
http://docs.astropy.org/en/stable/cosmology/
- 从红移到年龄
>>>from astropy.cosmology import FlatLambdaCDM >>>cosmo = FlatLambdaCDM(H0=70, Om0=0.3)
>>> lum_dis=cosmo.luminosity_distance(redshift) #计算光度距离
- 从年龄到红移
>>> import astropy.units as u >>> from astropy.cosmology import z_at_value >>> z_at_value(cosmos.age, 2 * u.Gyr)
单位转换
dL=lum_dis.to(u.cm)