A coronograph is a telescope with a circular disc that covers the Sun, allowing the viewer to study its gaseous outer halo, called the corona.
They had already passed through the nebula's outer halo of star-spawning hydrogen and it was possible to make out stars above and below them.
In particular, the outer halo is expected to be dominated by late-time accretion events.
Larger telescopes can distinguish the outer halo as well.
The data suggests that all the present outer halo globulars may have originally formed in dwarf spheroidals.
That outer halo, invisible in ordinary light, can be seen in ultraviolet light as a blue, football-shape envelope around the entire galaxy.
They have inner and outer halos, with roughly circular depressions.
The hydrogen then fell toward the center of the protogalaxy while the dark matter remained as an outer halo surrounding it.
It has been suggested that Leo I is a tidal debris stream in the outer halo of the Milky Way.
This is a round, diffuse cluster located in the outer halo of the Milky Way galaxy.