Hercules Globular Cluster (M13)
One of the brightest globular clusters in the northern sky, visible with binoculars as a fuzzy patch; telescopes begin to resolve its stars.
Globular cluster in Hercules. Magnitude 5.8.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 60° above the northern horizon at its highest; from Lethem (3.4° N), to 57° above the northern horizon. It is highest at midnight on the night of 30 May, in the middle of its season. The page works out tonight's rise, highest point and set for both towns in Guyana time (UTC-4), and where the Moon is.
What you'll see
- Your eyes: Visible to the eye only from a dark site, as a fuzzy star; lost in city skies.
- 10x50 binoculars: A round glow, brighter towards the middle.
- A small telescope (80 to 100 mm): A bright ball; at 100x its edge turns grainy and starts to resolve under dark skies.
- A camera: Spans about 40% of an APS-C frame at 2,000 mm (field 0.7° × 0.4°); needs a tracking mount.
How big, how bright, how far
- Size on the sky: 17′, 55% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 5.8. Fainter than Georgetown's faintest stars (4.3) but brighter than Lethem's (6.0).
- Distance: 22,200 light-years. The light reaching your eye left it about 22,000 years ago.
What it is made of
- Type
- Globular Cluster
- Distance
- Approx. 22,200 Lightyears
- True size
- Approx. 145 Lightyears diameter
- Old Stars (Hundreds of Thousands): Population II, metal-poor, gravitationally bound
- Minimal Gas and Dust: Most material consumed in early star formation
More deep-sky objects: M92 (Globular Cluster) · Globular Cluster M3 · Globular Cluster M5 · Wild Duck Cluster (M11) · Eagle Nebula (M16) · Coma Star Cluster (Melotte 111)