> from astropy.io import fits
> hdulist = fits.open('N20190326G0041i.fits')
文件上的信息。请注意，所有内容都在主HDU中。
> hdulist.info()
Filename: N20190326G0041i.fits
No. Name Ver Type Cards Dimensions Format
0 PRIMARY 1 PrimaryHDU 183 (190685, 28) float32
我可以访问完整的标头，但是它非常长。我在这篇文章的末尾包含了它。
> hdu = hdulist[0]
> hdu.header
但是，我只使用hdu.data获得了一部分数据
> hdu.data
array([[ 4.0630740e+02, 4.0631021e+02, 4.0631290e+02, ...,
1.0478779e+03, 1.0478831e+03, 1.0478882e+03],
[ 2.7955999e+01, 3.1493999e+01, 1.2378000e+01, ...,
-4.3614998e+00, -1.8785000e+00, -8.8672000e-01],
[ 2.8534999e+00, 2.8862000e+00, 2.9282999e+00, ...,
-6.1020999e+00, -5.2989998e+00, -5.1680999e+00],
...,
[ 1.7951000e+04, 2.9099000e+04, 3.5257000e+03, ...,
1.0594000e+03, 7.9347998e+02, 1.6349001e+02],
[ 3.1568999e+03, 3.1631001e+03, 3.2426001e+03, ...,
3.2828000e+02, 3.2062000e+02, 3.2189001e+02],
[ 3.3338000e+03, 3.3806001e+03, 3.4557000e+03, ...,
2.1803000e+02, 2.2574001e+02, 2.3003999e+02]], dtype=float32)
我通常将适合的文件打印为文本文件的操作是...
> table = hdulist[0].data
> print(table, file = open('test.txt','a'))
此“有效”，并输出与hdu.data在屏幕上打印的数据相同的摘录。
> [[ 4.0630740e+02 4.0631021e+02 4.0631290e+02 ... 1.0478779e+03
1.0478831e+03 1.0478882e+03]
[ 2.7955999e+01 3.1493999e+01 1.2378000e+01 ... -4.3614998e+00
-1.8785000e+00 -8.8672000e-01]
[ 2.8534999e+00 2.8862000e+00 2.9282999e+00 ... -6.1020999e+00
-5.2989998e+00 -5.1680999e+00]
...
[ 1.7951000e+04 2.9099000e+04 3.5257000e+03 ... 1.0594000e+03
7.9347998e+02 1.6349001e+02]
[ 3.1568999e+03 3.1631001e+03 3.2426001e+03 ... 3.2828000e+02
3.2062000e+02 3.2189001e+02]
[ 3.3338000e+03 3.3806001e+03 3.4557000e+03 ... 2.1803000e+02
2.2574001e+02 2.3003999e+02]]
此外，我使用memmap = True重复了上述所有操作，但得到的结果相同。
> from astropy.io import fits
> hdulist = fits.open('N20190326G0041i.fits', memmap = True)
我还尝试了便捷功能，但是产生的摘录与hdu.data完全相同。
> tbdata = fits.getdata('N20190326G0041i.fits')
> print(tbdata,file=open('test.txt','a'))
我还尝试了astropy.table包，但也无法使其正常工作。
> from astropy.table import Table
> t = Table.read(hdulist[0], format = 'fits')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/anaconda3/lib/python3.7/site-packages/astropy/table/connect.py", line 52, in __call__
out = registry.read(cls, *args, **kwargs)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/registry.py", line 523, in read
data = reader(*args, **kwargs)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/connect.py", line 195, in read_table_fits
memmap=memmap)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/hdu/hdulist.py", line 151, in fitsopen
lazy_load_hdus, **kwargs)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/hdu/hdulist.py", line 390, in fromfile
lazy_load_hdus=lazy_load_hdus, **kwargs)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/hdu/hdulist.py", line 1039, in _readfrom
fileobj = _File(fileobj, mode=mode, memmap=memmap, cache=cache)
File "/anaconda3/lib/python3.7/site-packages/astropy/utils/decorators.py", line 521, in wrapper
return function(*args, **kwargs)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/file.py", line 180, in __init__
self._open_filelike(fileobj, mode, overwrite)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/file.py", line 533, in _open_filelike
"method, required for mode '{}'.".format(self.mode))
OSError: File-like object does not have a 'write' method, required for mode 'ostream'.
但是，如果我使用
> t=Table.read(hdu.data, format='fits')
然后我得到另一个错误
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/anaconda3/lib/python3.7/site-packages/astropy/table/connect.py", line 52, in __call__
out = registry.read(cls, *args, **kwargs)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/registry.py", line 523, in read
data = reader(*args, **kwargs)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/connect.py", line 195, in read_table_fits
memmap=memmap)
File "/anaconda3/lib/python3.7/site-packages/astropy/io/fits/hdu/hdulist.py", line 147, in fitsopen
if not name:
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
我也曾在PyRAF中尝试过tprint和tdump，它仅给出错误“警告：”，没有其他有用的信息。我也尝试使用PyRaf中的wspectext函数将fits文件写入文本，但是无法这样做。
但是，我希望能够仅使用astropy的fits包将数据输出到文本文件。我已经使用来自各种望远镜管道的其他拟合文件完成了无数次操作，但是这次不起作用。任何帮助深表感谢。
文件的标题在下面。我想知道既然标头是用IDL编写的，那么我唯一能够访问信息的方法是通过IDL吗？在我看来，这不太可能。如果可能的话，我真的想避免使用IDL。我们在大学拥有站点许可证，但是在大流行期间我们不允许进入校园，并且我们的VPN功能不足。
> hdu.header
SIMPLE = T / Written by IDL:
BITPIX = -32 / Real*4 (complex, stored as float)
NAXIS = 2 / Number of axes
NAXIS1 = 190685 / Number of pixel columns
NAXIS2 = 28 / Number of pixel rows
INHERIT = F / No need to inherit global keywords
BZERO = 0. / Data is Unsigned Integer
BSCALE = 1. / Scale factor
IMAGESWV= 'CFHT DetCom v3.60.18 (Apr 20 2017)' / Image creation software version
OBSTYPE = 'OBJECT ' / Observation / Exposure type
EXPTYPE = 'OBJECT ' / See OBSTYPE
EXPTIME = 2561.0 / Integration time (seconds)
DARKTIME= 2561.0 / Dark current time (seconds)
DETECTOR= 'OLAPA ' / Science Detector
CCD = 'Unknown ' / Science Detector (use DETECTOR)
IMAGEID = 0 / CCD chip number
CHIPID = 0 / Use IMAGEID instead
DETSIZE = '[1:2048,1:4608]' / Total data pixels in full mosaic
RASTER = 'FULL ' / Active raster description
CCDSUM = '1 1 ' / Binning factors
CCDBIN1 = 1 / Binning factor along first axis
CCDBIN2 = 1 / Binning factor along second axis
PIXSIZE = 13.5 / Pixel size for both axes (microns)
AMPLIST = 'a,b ' / List of amplifiers for this image
CCDSIZE = '[1:2048,1:4608]' / Detector imaging area size
CCDSEC = '[21:2068,1:4608]' / Read out area of the detector (unbinned)
TRIMSEC = '[21:2068,4:4605]' / Useful imaging area of the detector
BSECA = '[1:20,1:4608]' / Overscan/prescan (bias) area from Amp A
BSECB = '[2069:2088,1:4608]' / Overscan/prescan (bias) area from Amp B
CSECA = '[21:1044,1:4608]' / Section in full CCD for DSECA
CSECB = '[1045:2068,1:4608]' / Section in full CCD for DSECB
DSECA = '[21:1044,1:4608]' / Imaging area from Amp A
DSECB = '[1045:2068,1:4608]' / Imaging area from Amp B
TSECA = '[21:1044,4:4605]' / Trim section for Amp A
TSECB = '[1045:2068,4:4605]' / Trim section for Amp B
MAXLIN = 65535 / Maximum linearity value (ADU)
SATURATE= 65535 / Saturation value (ADU)
GAINA = 1.10 / Amp A gain (electrons/ADU)
GAINB = 1.20 / Amp B gain (electrons/ADU)
RDNOISEA= 2.90 / Amp A read noise (electrons)
RDNOISEB= 2.90 / Amp B read noise (electrons)
DARKCUR = 0 / Dark current (e-/pixel/hour)
RDTIME = 30.00 / Read out time (sec)
CONSWV = 'olD=137,DCU=49' / Controller software DSPID and SERNO versions
DETSTAT = 'ok ' / Detector temp range (-105..-90)
DETTEM = -100.2 / Detector temp deg C = 745.502 + -0.278 * 3042
INSTRUME= 'GRACES ' / Instrument Name
ECAMFOC = -3.61 / ESPaDOnS camera focus position (mm)
EHARTPOS= 'OUT ' / ESPaDOnS hartmann position FULL/DOWN/UP/OUT
EEMSHUT = 'CLOSE ' / ESPaDOnS exposure meter shutter OPEN/CLOSED
EEMSTATE= 'OFF ' / ESPaDOnS exposure meter state ON/OFF
EEMCNTS = -9999 / ESPaDOnS exposure meter count average
ETSP1BEG= 17.38 / ESPaDOnS down mirror temp at start (deg C)
ETSP2BEG= 17.61 / ESPaDOnS camera temp at start (deg C)
ETSP3BEG= 17.55 / ESPaDOnS up mirror temp at start (deg C)
ETSP4BEG= 17.31 / ESPaDOnS hygrometer temp at start (deg C)
EPRSPBEG= -3.35 / ESPaDOnS relative pressure at start (mb)
ERHSPBEG= 21.11 / ESPaDOnS relative humidity at start (%)
ETSP1END= 17.38 / ESPaDOnS down mirror temp at end (deg C)
ETSP2END= 17.59 / ESPaDOnS camera temp at end (deg C)
ETSP3END= 17.55 / ESPaDOnS up mirror temp at end (deg C)
ETSP4END= 17.31 / ESPaDOnS hygrometer temp at end (deg C)
EPRSPEND= -3.29 / ESPaDOnS relative pressure at end (mb)
EREADSPD= 'Slow: 2.90e noise, 1.15e/ADU, 30s' / ESPaDOnS det read out xslow/slow
GSLIPOS = 'TWOSLICE' / GRACES slicer bench position (# and mm)
GSLICER = 'TWOSLICE' / GRACES slicer position (# and deg)
GDEKKER = 'TWOSLICE' / GRACES dekker position (# and mm)
GPMIRROR= 'GEMINI ' / GRACES pickoff mirror position (# and mm)
GFIBMODE= 'GRACES ' / GRACES fiber position (ESPADONS or GRACES)
O_BSCALE= 1.00000 / Original BSCALE Value
RAWIQ = '85-percentile' /Raw Image Quality
RAWCC = '50-percentile' /Raw Cloud Cover
RAWWV = '20-percentile' /Raw Water Vapour/Transparency
RAWBG = '50-percentile' /Raw Background
TELESCOP= 'Gemini-North' /Gemini-North
EPOCH = 2000.00 /Epoch for Target coordinates
CRPA = 80.7411581783 /Current Cass Rotator Position Angle
AIRMASS = '1.271 ' /Mean airmass for the observation
AMSTART = '1.365 ' /Airmass at start of exposure
AMEND = '1.191 ' /Airmass at end of exposure
HA = '-03:02:41.87' /Hour Angle Sexagesimal
HAD = '-3.0449640' /Hour Angle Decimal
OBSCLASS= 'science ' /Observe class
INSTMODE= 'Spectroscopy, star+sky' /Observing mode
RAWPIREQ= 'YES ' /PI Requirements Met
RAWGEMQA= 'USABLE ' /Gemini Quality Assessment
COMMENT ----------------------------------------------------
COMMENT | Processed by the CFHT OPERA Open Source Pipeline |
COMMENT ----------------------------------------------------
COMMENT opera-1.0.1228 build date Fri May 19 18:53:30 HST 2017
COMMENT Processing Date
COMMENT ---------------
COMMENT Mon May 4 14:50:27 HST 2020
COMMENT ------------------------------------------------------------------------
COMMENT 20
SNR22 = '0.50798 / 0.61051' / snr per spectral / ccd bin
SNR23 = '0.84309 / 1.0133' / snr per spectral / ccd bin
SNR24 = '1.2171 / 1.4627' / snr per spectral / ccd bin
SNR25 = '1.9608 / 2.3567' / snr per spectral / ccd bin
SNR26 = '2.1154 / 2.5425' / snr per spectral / ccd bin
SNR27 = '2.1107 / 2.5368' / snr per spectral / ccd bin
SNR28 = '2.2236 / 2.6725' / snr per spectral / ccd bin
SNR29 = '2.1241 / 2.5528' / snr per spectral / ccd bin
SNR30 = '2.2457 / 2.6991' / snr per spectral / ccd bin
SNR31 = '1.9948 / 2.3975' / snr per spectral / ccd bin
SNR32 = '1.6974 / 2.04' / snr per spectral / ccd bin
SNR33 = '1.4978 / 1.8001' / snr per spectral / ccd bin
SNR34 = '1.2949 / 1.5562' / snr per spectral / ccd bin
SNR35 = '1.3562 / 1.63' / snr per spectral / ccd bin
SNR36 = '1.0198 / 1.2257' / snr per spectral / ccd bin
SNR37 = '1.5021 / 1.8053' / snr per spectral / ccd bin
SNR38 = '1.01 / 1.2139' / snr per spectral / ccd bin
SNR39 = '0.71061 / 0.85405' / snr per spectral / ccd bin
SNR40 = '0.59577 / 0.71603' / snr per spectral / ccd bin
SNR41 = '0.62022 / 0.74541' / snr per spectral / ccd bin
SNR42 = '0.57458 / 0.69056' / snr per spectral / ccd bin
SNR43 = '0.52749 / 0.63397' / snr per spectral / ccd bin
SNR44 = '0.49149 / 0.5907' / snr per spectral / ccd bin
SNR45 = '0.48021 / 0.57714' / snr per spectral / ccd bin
SNR46 = '0.50494 / 0.60687' / snr per spectral / ccd bin
SNR47 = '0.52551 / 0.63159' / snr per spectral / ccd bin
SNR48 = '0.5106 / 0.61367' / snr per spectral / ccd bin
SNR49 = '0.42632 / 0.51237' / snr per spectral / ccd bin
SNR50 = '0.42451 / 0.5102' / snr per spectral / ccd bin
SNR51 = '0.42025 / 0.50508' / snr per spectral / ccd bin
SNR52 = '0.41137 / 0.49441' / snr per spectral / ccd bin
SNR53 = '0.41708 / 0.50127' / snr per spectral / ccd bin
SNR54 = '0.41904 / 0.50362' / snr per spectral / ccd bin
SNR55 = '0.4284 / 0.51487' / snr per spectral / ccd bin
HRV = -8.9311 / Heliocentric RV correction (km/s)
HRVLUNAR= 0.0125599 / lunar component of HRV correction (km/s)
HRVORBIT= -9.19911 / orbital component of HRV correction (km/s)
HRVDIURN= 0.255451 / diurnal component of HRV correction (km/s)
HJDUTC = 2458568.79603 / Heliocentric Julian date (UTC) mid-exposure
HJDTT = 2458568.796831 / Heliocentric Julian date (TT) mid-exposure
TELLRV = 0. / telluric RV correction (km/s)
TELLERR = 0. / telluric RV correction error (km/s)
REDUCTIO= 'Intensity' / Type of reduction
NORMAL = '2 ' / Normalized and Un-normalized Data
COMMENT File contains automatic wavelength correction and uncorrected data.
COL1 = 'Wavelength' / Normalized
COL2 = 'Star ' / Normalized
COL3 = 'Sky ' / Normalized
COL4 = 'Star+sky' / Normalized
COL5 = 'ErrorBarStar' / Normalized
COL6 = 'ErrorBarSky' / Normalized
COL7 = 'ErrorBarStar+Sky' / Normalized
COL8 = 'Wavelength' / UnNormalized
COL9 = 'Star ' / UnNormalized
COL10 = 'Sky ' / UnNormalized
COL11 = 'Star+sky' / UnNormalized
COL12 = 'ErrorBarStar' / UnNormalized
COL13 = 'ErrorBarSky' / UnNormalized
COL14 = 'ErrorBarStar+Sky' / UnNormalized
COL15 = 'Wavelength' / Normalized, no autowave correction
COL16 = 'Star ' / Normalized, no autowave correction
COL17 = 'Sky ' / Normalized, no autowave correction
COL18 = 'Star+sky' / Normalized, no autowave correction
COL19 = 'ErrorBarStar' / Normalized, no autowave correction
COL20 = 'ErrorBarSky' / Normalized, no autowave correction
COL21 = 'ErrorBarStar+Sky' / Normalized, no autowave correction
COL22 = 'Wavelength' / UnNormalized, no autowave correction
COL23 = 'Star ' / UnNormalized, no autowave correction
COL24 = 'Sky ' / UnNormalized, no autowave correction
COL25 = 'Star+sky' / UnNormalized, no autowave correction
COL26 = 'ErrorBarStar' / UnNormalized, no autowave correction
COL27 = 'ErrorBarSky' / UnNormalized, no autowave correction
COL28 = 'ErrorBarStar+Sky' / UnNormalized, no autowave correction
我有一个很大的文件（21.4 MB）。我想将其内容打印到一个文本文件中，但是只能访问它的一部分。我正在寻找将整个文件转换为文本格式的帮助。 > ...