M52 (Open Cluster)
A rich open cluster in Cassiopeia, about 5,100 light-years away. The Bubble Nebula is 0.6° away, and the bright red star near its centre is not a member.
Open cluster in Cassiopeia. Magnitude 6.9.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 35° above the northern horizon at its highest; from Lethem (3.4° N), to 32° above the northern horizon. It is highest at midnight on the night of 9 Sep, 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: Not visible to the eye. It lies 6.0° north-west of Caph.
- 10x50 binoculars: A small hazy knot with a few stars resolved. The Bubble Nebula (NGC 7635) is 0.6° away.
- A small telescope (80 to 100 mm): A rich glow of faint stars with one bright orange star; the Bubble Nebula is 0.6° to the south-west.
- A camera: Tiny on camera: it needs 2,000 mm or more of focal length on a tracking mount. The Bubble Nebula is in the same frame.
How big, how bright, how far
- Size on the sky: 9.9′, 32% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 6.9. Fainter than the faintest stars in Georgetown (4.3) and Lethem (6.0): binoculars or a telescope.
- Distance: 5,100 light-years. The light reaching your eye left it about 5,100 years ago.
- True size: 15 light-years across its catalogued outline; light crosses it in 15 years.
Apparent size from OpenNGC (Mattia Verga), CC-BY-SA-4.0.
What it is made of
- Type
- Open cluster
- Mass
- About 5,600 times the Sun's mass, in its stars
- Age
- About 84 million years (range 53 million years to 130 million years)
- Notable
- The conspicuous red star near its centre is a foreground star, not a member of the cluster.
What is in it, not measured:
- Stars born together: from one cloud of gas, at one time
How we know: Distance from Gaia parallaxes of its stars: Hunt & Reffert 2024, A&A 686, A42 (Gaia DR3 cluster catalogue, VizieR J/A+A/686/A42), retrieved 2026-10-21: NGC 7654 1,571 pc; statistical 5,118-5,129 ly (16th-84th percentile); Gaia DR3 parallax zero-point systematics (about 0.02 mas) add about 3%. True size: the apparent size times the distance (apparent size: OpenNGC (Mattia Verga, CC BY-SA 4.0), commit 4e2398a2). Mass: Hunt & Reffert 2024, A&A 686, A42 (Gaia DR3 cluster catalogue, VizieR J/A+A/686/A42), retrieved 2026-10-21, NGC 7654: total 5,581 ± 310 Suns.
More deep-sky objects: Wizard Nebula (NGC 7380) · NGC 7789 (Caroline's Rose / White Rose Cluster) · IC 1396 (Elephant's Trunk Nebula) · NGC 457 (ET Cluster / Owl Cluster) · M103 (Open Cluster) · M39 (Open Cluster)