Note
Go to the end to download the full example code.
Read and plot spectra with SpectraContainer#
Note
This tutorial is not final. It will be finished once all the core
functionalities of SpectraContainer are implemented.
Introduction to using madcubapy to read and plot MADCUBA spectra.
We start by importing the necessary libraries for this tutorial.
from madcubapy.io import SpectraContainer
import matplotlib.pyplot as plt
Reading the spectra file#
Spectra are exported from MADCUBA in a single FITS file containing a bintable
with each one of the spectra inside. This FITS file is then packaged
alongside the history file inside a .spec archive. With
the SpectraContainer class we can open MADCUBA’s .spec
files alongside their history tables.
We can read the .spec file with the
SpectraContainer.read() method, and
the corresponding history file will be loaded as well if
present.
spectra_container = SpectraContainer.read(
"../examples/data/IRAS16293_position_8_TM2_spectra.spec")
Note
Due to how MADCUBA saves some FITS header cards, several astropy
warnings can pop up when reading spectra. Usually these warnings are
incorrectly written units, or units using non-standard conventions.
The spectra are stored in the bintable attribute, which is an Astropy
table contaning the data and header information for every spectra.
# Show the first two spectra inside as an example
spectra_container.bintable[0:2]
The spectrum data is contained in the DATA and XAXIS columns
alongside their units if correctly parsed from the header.
We can quickly plot a spectrum by accesing these values
index = 6
fig, ax = plt.subplots(1, 1, figsize=(7,5))
x = spectra_container.bintable[index]['XAXIS']
x_unit = spectra_container.bintable[index].table['XAXIS'].unit
y = spectra_container.bintable[index]['DATA']
y_unit = spectra_container.bintable[index].table['DATA'].unit
ax.plot(x, y, drawstyle='steps-mid')
ax.set_xlabel(f"Freq [{x_unit}]")
ax.set_ylabel(f"S [{y_unit}]")
plt.show()
Total running time of the script: (0 minutes 0.111 seconds)