使用正确的wcs变换使用aplpy绘制fits图像

Question

我想用aplpy绘制一个fits文件，但得到了以下错误：

INFO: The WCS transformation has more axes (3) than the image it is associated with (2) [astropy.wcs.wcs]
ERROR: IndexError: list index out of range [aplpy.wcs_util]

如果我删除标题关键字CTYPE3，CD3_3，WAT3_001，那么我不会再得到错误，但是当绘制fits文件时，我看到WCS转换没有正确地完成，RA和DEC坐标到处都是。

这是标题：

HCG89_halpha_plot.fits[2929,2881][real]: HCG89-SII
No bad pixels, min=0., max=0. (old)
Line storage mode, physdim [2929,2881], length of user area 5144 s.u.
Created Tue 15:40:54 28-Jan-2014, Last modified Thu 22:20:03 30-Jan-2014
Pixel file "HCG89_halpha_plot.fits" [ok]
ORIGIN  = 'NOAO-IRAF FITS Image Kernel July 2003' / FITS file originator
IRAF-TLM= '2014-01-30T19:20:03' / Time of last modification
OBJECT  = 'HCG89-SII'          / Name of the object observed
DATE-OBS= '2013-10-11T00:14:11.700' / Date of observation
DATE    = '2014-01-28T12:40:54' / Date Format is YYYY-MM-DD
TIME    = '00:14:11.07 to 00:19:11.40' / ~ Start & Stop of Exposure
N_PARAM =                   80 / Number of Parameters
TELESCOP= 'SOAR 4.1m'
INSTRUME= 'Goodman Spectrograph'
NOTES   = '        '
RA      = '21:20:09.042'       / right ascension [hh:mm:ss.sss]
DEC     = '-3:55:23.160'       / declination [dd:mm:ss.sss]
AIRMASS =                 1.13 / airmass at approx. start of exposure
UT      = '00:14:10.9'         / time at approx. start of exposure [UTC]
FOCUS   =              -1021.0 / SOAR telescope focus
MOUNT_AZ=              17.1482 / SOAR mount azimuth
MOUNT_EL=              62.2622 / SOAR mount elevation
ROTATOR =              228.003 / Nasymth cage rotator angle [deg]
POSANGLE=                360.0 / position angle [deg. E of N]
SEEING  =                 -1.0 / DIMM seeing [arcsec]
LST     = '20:50:17.4'         / Local Sidereal Time  [hh:mm:ss.sss]
OBSRA   = '21:20:09.946'       / target right ascension [hh:mm:ss.sss]
OBSDEC  = '-3:55:32.480'       / target declination  [hh:mm:ss.sss]
CAM_ANG =             0.014461 / camera angle [deg]
GRT_ANG =                0.661 / grating angle [deg]
CAM_TARG=                  0.0 / camera target [deg]
GRT_TARG=                0.661 / grating target [deg]
CAM_FOC =                  660 / camera focus
COLL_FOC=                 1002 / collimator focus
FILTER  = 'SII     '           / primary filter wheel
FILTER2 = '<NO FILTER>'        / secondary filter wheel
GRATING = '<NO GRATING>'       / VPH grating [1/mm]
SLIT    = '<NO MASK>'          / slit [arcsec]
COL_TEMP=            10.421875 / coll ext temp (deg C)
CAM_TEMP=            14.234375 / cam ext temp (deg C)
EXPTIME =                300.0 / integration time
RDNOISE =                 4.74 / CCD readnoise [e-]
GAIN    =                  1.4 / CCD gain [e-/ADU]
OBSTYPE = 'OBJECT  '           / observation type
OBSERVER= '        '
PROPOSAL= '        '
EQUINOX =               2000.0 / equinox of coordinates
CRPIX1  =     1477.39599990845 / Reference pixel on axis 1
CRPIX2  =     1488.23082170899 / Reference pixel on axis 2
CRVAL1  =        320.041401353 / Value at ref. pixel on axis 1
CRVAL2  =       -3.91652009277 / Value at ref. pixel on axis 2
CTYPE1  = 'RA---TAN'           / Type of co-ordinate on axis 1
CTYPE2  = 'DEC--TAN'           / Type of co-ordinate on axis 2
PC1_1   =    0.999884048946387 / Transformation matrix element
PC1_2   =   0.0152278909432213 / Transformation matrix element
PC2_1   =  -0.0140395410920601 / Transformation matrix element
PC2_2   =                  1.0 / Transformation matrix element
MJD-OBS =     56576.0098576389 / Modified Julian Date of observation
RADESYS = 'FK5     '           / Reference frame for RA/DEC values
DISPAXIS=                    1
DETSIZE = '[1:4096,1:4096]'
TRIMSEC = '[1:3096,1:3096]'
CCDSIZE = '[1:4096,1:4096]'
CCDSUM  = '1 1     '
OPENTIME= '00:14:11.611'       / GPS-Synched Time for Shutter Open (UT)
INSTRUME= 'Goodman Spectrograph'
COMMENT  Triggered Acquisition, Exp Time= 05:00
WCSDIM  =                    3
LTM1_1  =                  1.0
LTM2_2  =                  1.0
LTM3_3  =                  1.0
WAXMAP01= '1 0 2 0 0 0 '
WAT0_001= 'system=physical'
WAT1_001= 'wtype=linear axtype=ra'
WAT2_001= 'wtype=linear axtype=dec'
WAT3_001= 'wtype=linear'
LTV1    =    -159.604000091553
LTV2    =    -134.766998291016
IMCMB001= '0073.HCG89-SII_scaled.fits'
IMCMB002= '0074.HCG89-SII_scaled.fits'
IMCMB003= '0079.HCG89-SII_scaled.fits'
IMCMB004= '0080.HCG89-SII_scaled.fits'
IMCMB005= '0083.HCG89-SII_scaled.fits'
IMCMB006= '0084.HCG89-SII_scaled.fits'
NCOMBINE=                    6
CTYPE3  = 'LINEAR  '
CD1_1   =  4.03250815042544E-5
CD2_2   =  4.04084336509694E-5
CD3_3   =                   1.

Answer 1

我不确定，因为我无法访问您的图像，但是您有多扩展名的FITS文件吗？如果这样做，您可能会遇到与我相同的错误(Find physical coordinates of a pixel in a fits file with python)。

检查以确保您使用的是连接到科学数据的HDU和标头。