M25 (Open Cluster IC 4725)
A large and bright open cluster in Sagittarius, a fine binocular object containing the Cepheid variable star U Sagittarii.
Open cluster in Sagittarius. Magnitude 4.6.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 64° above the southern horizon at its highest; from Lethem (3.4° N), to 67° above the southern horizon. It is highest at midnight on the night of 27 Jun, 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 hazy knot of stars; lost in city skies.
- 10x50 binoculars: Resolves into dozens of stars.
- A small telescope (80 to 100 mm): Dozens to hundreds of stars at low power.
- A camera: Spans about 40% of an APS-C frame at 1,000 mm (field 1.3° × 0.9°); needs a tracking mount.
How big, how bright, how far
- Size on the sky: 32′, 1.0 Moons across (the Moon is about 31′ wide).
- Brightness: magnitude 4.6. Fainter than Georgetown's faintest stars (4.3) but brighter than Lethem's (6.0).
- Distance: 2,100 light-years. The light reaching your eye left it about 2,100 years ago.
What it is made of
- Type
- Open cluster
- Distance
- Approx. 2,100 Lightyears
- True size
- Approx. 20 Lightyears across
- Age
- about 96 million years (range 56 million years to 130 million years)
- Notable
- Bright and loose: about 96 million years old at 2,100 light-years.
More deep-sky objects: Globular Cluster M22 · Eagle Nebula (M16) · Wild Duck Cluster (M11) · Butterfly Cluster (M6) · Ptolemy Cluster (M7) · M55 (Globular Cluster)