我正在按照Astropy文档中的2D Cutout示例进行操作。
我的FITS文件的标题：
SIMPLE = T / file does conform to FITS standard
BITPIX = -32 / number of bits per data pixel
NAXIS = 3 / number of data axes
NAXIS1 = 512 / length of data axis 1
NAXIS2 = 512 / length of data axis 2
NAXIS3 = 3 / length of data axis 3
EXTEND = T / FITS dataset may contain extensions
COMMENT FITS (Flexible Image Transport System) format is defined in 'Astronomy
COMMENT and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H
SURVEY = 'DECaLS '
VERSION = 'DR8-south'
IMAGETYP= 'image '
BANDS = 'grz '
BAND0 = 'g '
BAND1 = 'r '
BAND2 = 'z '
CTYPE1 = 'RA---TAN' / TANgent plane
CTYPE2 = 'DEC--TAN' / TANgent plane
CRVAL1 = 186.11382 / Reference RA
CRVAL2 = 0.15285422 / Reference Dec
CRPIX1 = 256.5 / Reference x
CRPIX2 = 256.5 / Reference y
CD1_1 = -7.27777777777778E-05 / CD matrix
CD1_2 = 0. / CD matrix
CD2_1 = 0. / CD matrix
CD2_2 = 7.27777777777778E-05 / CD matrix
IMAGEW = 512. / Image width
IMAGEH = 512. / Image height
到目前为止，我已经尝试过：
from astropy.coordinates import SkyCoord
from astropy.wcs import WCS
position = SkyCoord(hdu[0].header['CRVAL1']*u.deg,hdu[0].header['CRVAL2']*u.deg)
size = 200*u.pixel
wcs1 = WCS(hdu[0].header)
cutout = Cutout2D(hdu[0].data[0], position ,size, wcs = wcs1 )
我在最后一行遇到错误。错误：
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-142-7cc21a13e941> in <module>
----> 1 cutout = Cutout2D(hdu[0].data[0], position ,size, wcs = wcs1 )
/Applications/anaconda3/lib/python3.7/site-packages/astropy/nddata/utils.py in __init__(self, data, position, size, wcs, mode, fill_value, copy)
714 if wcs is not None:
715 self.wcs = deepcopy(wcs)
--> 716 self.wcs.wcs.crpix -= self._origin_original_true
717 self.wcs.array_shape = self.data.shape
718 if wcs.sip is not None:
ValueError: operands could not be broadcast together with shapes (3,) (2,) (3,)
我的猜测是因为文件中的naxis = 3，文档假定naxis =2。尽管我不确定这是否是这里的实际问题。任何人都可以帮助解决此错误吗？
由于您的WCS是3d，但您将获得2d切口，因此需要删除第3维。尝试cutout = Cutout2D(hdu[0].data[0], position ,size, wcs = wcs1.celestial )，其中.celestial是在WCS中删除三维尺寸的便捷工具。