12. Crosswalk

Comparing functionality in NEMO with like-wise programs in other packages can be helpful for onboarding. Here are a few examples:

Comparing NEMO programs with those in other packages

NEMO

python

CASA

MIRIAD

tabtrend

numpy.diff()

N/A

N/A

tabplot

plt.plot()

N/A

N/A

fitsccd

hdu=astropy.io.fits.open()

importfits()

fits op=xyin

ccdfits

hdu=astropy.io.fits.open()

exportfits()

fits op=xyout

ccdprint

print(hdu[0].data)

???

imlist

ccdmom

np.sum()

immoments()

moment

ccdmath

numpy

immath()

maths

ccdstat

hdu[0].data.std()

imstat()

imstat

The CASA users guide has a more expanded table of this, just comparing CASA with MIRIAD and CLICK. There it is called a CASA-MIRIAD and CASA-CLIC dictionary.

12.1. Example

An expanded example how to read a FITS (image) into the respective systems is as follows, plus some sample commands one can in the respective package:

# NEMO
$ fitsccd ngc0001.fits ngc0001.ccd
$ ccdhead ngc0001.ccd
$ ccdplot ngc0001.ccd yapp=/xs

# PYTHON
In [1]: hdu = astropy.io.fits.open('ngc0001.fits')
In [2]: print(hdu[0].header)
In [2]: plt.imshow(hdu[0].data)

# CASA
CASA <1>: importfits('ngc0001.fits', 'ngc0001.im')
CASA <2>: imhead('ngc0001.im')
CASA <2>: imview('ngc0001.im')

# MIRIAD
$ fits in=ngc0001.fits out=ngc0001.mir op=xyin
$ imhead in=ngc0001.mir
$ implot in=ngc0001.mir device=/xs