MacPorts offers a reliable way to install a Python distribution on MacOSX with most of the needed libraries for iSpec. However, it is important to know that sometimes the installation can take time because, depending on your operating system version, it might compile all the packages/libraries from source code. On the other hand, MacPorts is completely open source without limiting licenses and it can be used to install other free software apart from python.
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
source $HOME/.bash\_profile
sudo port selfupdate
sudo port upgrade outdated
sudo port -N install python38
sudo port select --set python python38
sudo port -N install py38-gnureadline
sudo port -N install py38-tkinter
sudo port -N install py38-numpy
sudo port -N install py38-scipy
sudo port -N install py38-matplotlib
sudo port -N install py38-astropy
sudo port -N install py38-pandas
sudo port -N install py38-cython
sudo port select --set cython cython38
sudo port -N install py38-statsmodels
sudo port -N install py38-lockfile
sudo port -N install py38-dill
sudo port -N install py38-pip
sudo port select --set pip pip38
sudo port -N install py38-ipython
sudo port select --set ipython py38-ipython
sudo port -N install py38-pudb
make clean
make spectrum
PATH=/usr/bin:$PATH make turbospectrum
PATH=/usr/bin:$PATH make moog