Contents

Astronomy — Interactive Viewers

Several interactive widgets are available that allow interactive exploration of various astronomical image collections.

Warning

Many interactive ipywidgets will only work in the context of a live notebook.

ipyaladin

import ipyaladin as ipyal

aladin= ipyal.Aladin(target='messier 51', fov=1)

# When using this in an interactive notebook,
# we can use https://github.com/innovationOUtside/nb_cell_dialog extension
# to pop the cell or cell output out into a floating widget 
# rather than have it anchored in a fixed place in the linear flow of a notebook
aladin

Note

If the nb_cell_dialog extension is installed, the widget can be popped out of the code cell output area and into its own floating widget. This allows the widget to remain in view as commands are issued throughout the notebook to change the WWT view rendered by it.

Set a new target object by name:

aladin.target='M82'

Set the zoom level:

aladin.fov=0.3

Enable the layers control in the widget:

aladin.show_layers_control=True

Set a layer explicitly:

aladin.survey = 'P/2MASS/color'

Look up objects in a particular area:

from astroquery.simbad import Simbad

table = Simbad.query_region("M82", radius="4 arcmin")

And overlay objects on the image in the widget viewer:

aladin.add_table(table)

pywwt

The pywwt package provides an interactive widget for making observations using the AAS World Wide Telescope, a suite of tools that provide access to a wide variety of astronomical visualisations.

Start by loading the default widget:

from pywwt.jupyter import WWTJupyterWidget

wwt = WWTJupyterWidget()

# When using this in an interactive notebook,
# we can use https://github.com/innovationOUtside/nb_cell_dialog extension
# to pop the cell or cell ouput out into a floating widget 
# rather than have it anchored in a fixed place in the linear flow of a notebook
wwt

A series of code cell commands then configure the view displayed by the widget.

Note

If the nb_cell_dialog extension is installed, the widget can be popped out of the code cell output area and into its own floating widget. This allows the widget to remain in view as commands are issued throughout the notebook to change the WWT view rendered by it.

Enable constellation boundaries:

wwt.constellation_boundaries = True

Enable constellation figures:

wwt.constellation_figures = True

View telescope layers that are available:

wwt.available_layers[:5]

['2MASS: Catalog (Synthetic, Near Infrared)',
 '2MASS: Two Micron All Sky Survey (Synthetic, Near Infrared)',
 '2Mass: Imagery (Infrared)',
 'Big Picture (Optical)',
 'Black Sky Background']

Bring a particular object into view at a specified magnification:

from astropy import units as u
from astropy.coordinates import SkyCoord

coord = SkyCoord.from_name('Alpha Centauri')
wwt.center_on_coordinates(coord, fov=10 * u.deg)

Enable foreground and background layers:

wwt.background = wwt.imagery.gamma.fermi
wwt.foreground = wwt.imagery.other.planck
wwt.foreground_opacity = .75

Foreground and background layer views, and the relative opoacity, can also be controlled via interactive widgets:

wwt.layer_controls

Change of View

Onservations can be rendered for particular views:

wwt.available_views

['callisto',
 'earth',
 'europa',
 'ganymede',
 'io',
 'jupiter',
 'mars',
 'mercury',
 'milky way',
 'moon',
 'neptune',
 'panorama',
 'pluto',
 'saturn',
 'sky',
 'solar system',
 'sun',
 'universe',
 'uranus',
 'venus']

For example, we can view Saturn:

wwt.set_view('jupiter')

Or the whole Milky Way:

wwt.set_view('milky way')

We can also draw constellations:

from astropy import units as u
from astropy.coordinates import concatenate, SkyCoord

bd = concatenate((SkyCoord.from_name('Alkaid'),  # stars in Big Dipper
                  SkyCoord.from_name('Mizar'),
                  SkyCoord.from_name('Alioth'),
                  SkyCoord.from_name('Megrez'),
                  SkyCoord.from_name('Phecda'),
                  SkyCoord.from_name('Merak'),
                  SkyCoord.from_name('Dubhe')))

wwt.center_on_coordinates(SkyCoord.from_name('Megrez'))
line = wwt.add_line(bd, width=3 * u.pixel)

A particular view can be save as an HTML bundle with the command: wwt.save_as_html_bundle()