具有多个 headers 的 astropy FITS

Question

我正在尝试在 Python 中创建一个 FITS 文件，但在同时编译 headers 和 PrimaryHDU 时我似乎遇到了问题。

我做了一个简单的例子，它给出了我得到的错误：

import numpy as np
from astropy.io import fits

a = np.ones([5,5])
hdu = fits.PrimaryHDU(a)
hdr = fits.Header()
hdr['NPIX1'] = 60
hdr['NPIX2'] = 60
hdr['CRPIX1'] = 0
hdr['CRPIX2'] = 0
primary_hdu = fits.PrimaryHDU(header=hdr)
hdul = fits.HDUList([primary_hdu, hdu])
hdul.writeto('table4.fits')

当运行这段代码时，我得到以下错误：

VerifyError: Verification reported errors: HDUList's element 1 is not an extension HDU. Note: astropy.io.fits uses zero-based indexing.

我看到一些帖子声称这可能与导出时 PrimaryHDU 需要成为 HDUList 中的第一个有关，但查看我的代码，我相信我已经这样做了。

如有任何帮助，将不胜感激，谢谢。

Answer 1

注意错误信息：

VerifyError: Verification reported errors: HDUList's element 1 is not an extension HDU. Note: astropy.io.fits uses zero-based indexing.

HDUList中的第二项是also a PrimaryHDU，这不是有效的扩展HDU（Primary这里的意思是首创且独一无二）。

让那个 HDU 成为 ImageHDU，事情就会成功：

import numpy as np
from astropy.io import fits

a = np.ones([5,5])
hdu = fits.ImageHDU(a)     # Don't use a `PrimaryHDU` here
hdr = fits.Header()
hdr['NPIX1'] = 60
hdr['NPIX2'] = 60
hdr['CRPIX1'] = 0
hdr['CRPIX2'] = 0
primary_hdu = fits.PrimaryHDU(header=hdr)
hdul = fits.HDUList([primary_hdu, hdu])
hdul.writeto('table4.fits')

具有多个 headers 的 astropy FITS

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