Observe M13’s ‘propeller’
Difficulty level: Beginner to Intermediate
The globular cluster M13 in the constellation of Hercules is easily the finest example of its kind in the night skies of the northern hemisphere. In a modest telescope of around six to eight inches it appears as a ball-shaped, huddled mass of countless tiny points of light.
For our final project in this article we’re going to look for a particular feature in this beautiful cluster. In M13’s southeastern corner the arrangement of stars along our line of sight is such that there is what looks like the (slightly transparent) silhouette of a three-bladed ‘propeller’ overlaid on the granular texture of the cluster.
If you struggle to see this feature try using averted vision, or observing from a site away from light pollution. Or, if it’s a larger instrument you need, why not visit your local astronomical society on an observing evening when they may have larger scopes on hand to help you catch sight of this intriguing cosmic curiosity.
The ghostly image of a three-armed propeller emerges from M13