图像数据

支持在统一I/O接口中读写CCD图像数据 CCDData class 使用FITS文件格式：

>>> # Read CCD image
>>> from astropy.nddata import CCDData
>>> ccd = CCDData.read('image.fits')

>>> # Write back CCD image
>>> ccd.write('new_image.fits')

请注意，该单元存储在 BUNIT 关键字，如果存在，则从标头中读取。

有关阅读和写作可用关键字参数的详细帮助，可通过 help() 方法如下：：

>>> from astropy.nddata import CCDData
>>> CCDData.read.help('fits')  # Get help on the CCDData FITS reader
=========================================
CCDData.read(format='fits') documentation
=========================================
...
>>> CCDData.write.help('fits')  # Get help on the CCDData FITS writer
==========================================
CCDData.write(format='fits') documentation
==========================================
...