Messier 3
Globular star cluster • Canes Venatici • 34,000 light-years from Earth
🔭
Askar 130PHQ
📷
ZWO ASI 2600MC Pro
🌃
Bortle 8
⏱️
5 hours
🗓️
March 2026
Overview
Messier 3 (usually abbreviated to M3) is a dense globular cluster located around 34,000 light years from Earth in the constellation Canes Venatici. It contains roughly 500,000 stars packed into a tightly bound spherical swarm. Formed around 11.4 billion years ago, M3 is more than twice as old as the Earth, making it a striking example of the ancient stellar populations that orbit the Milky Way, and an excellent target for urban astrophotographers.
Background
The cloud seems unending right now, so I need to take advantage of any gaps. This means that brighter targets are on the menu; anything I can nab in just a few hours. M3 fits the bill, and I was able to use my Askar 130PHQ telescope and ZWO ASI 2600MC Pro camera to collect five hours of data, which is far below what I normally aim for, but it’s ok for globulars.
The Moon was almost full and nearby too, which made things a bit harder, but don’t let anyone say you can’t photograph broadband targets when the Moon’s up!
I also somehow messed up my Flats, but luckily the resulting aberration was toward the edge of the frame, so I simply cropped the problem away…
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Explore the field
Objects in this field 1 object
1 object
No matching objects.
- M3M 3
- Globular clusterAlso catalogued as NGC 5272
About the labels and credits
Positions and outlines are calculated from a plate solution of this photograph. Outlines are catalogue guides and may not follow every visible filament. Additional catalogue objects may be faint or indistinct in this exposure.
Plate solving and annotation data: SkySolver, by Dominik Sito. Stars: Gaia DR3 and Hipparcos (ESA). Deep-sky data: OpenNGC © Mattia Verga (CC BY-SA 4.0), SIMBAD and VizieR (CDS). Names: Wikipedia (CC BY-SA 4.0) and IAU WGSN. Catalogue overlay adaptations, including styling and selected display names, are shared under CC BY-SA 4.0. Photograph © Lee Pullen.
Close-up
Science
M3 is an ancient stellar orb. Its stars formed when the Milky Way was still young, making the cluster a relic from the early history of our galaxy.
Over immense stretches of time, gravitational encounters between its stars have gradually smoothed out any original irregularities. Each close pass allows stars to exchange tiny amounts of energy, and after billions of these interactions the cluster has settled into a stable, nearly spherical structure.
There’s no sharp edge marking the end of M3. The density of stars decreases steadily from the brilliant central core toward the cluster’s faint outer regions, known as the tidal boundary. Here the gravitational pull of the Milky Way begins to compete with the cluster’s own gravity, gently tugging at its outermost stars. Over vast timescales some of these stars may escape entirely, drifting away to become part of the Galaxy’s halo.
Imaging details
- Total exposure
- 5 hours
- Dates captured
- 4 & 5 March 2026 (one night)
- Location and sky
- Bristol, UK (Bortle 8)
Equipment and software
- Telescope
- Askar 130PHQ Flatfield Astrograph
- Camera
- ZWO ASI 2600MC Pro
- Mount
- StellarDrive X 6R PRO
- Guiding
- Askar M54 OAG and ZWO ASI 220MM Mini
- Control
- ASIAIR Plus
- Software
- PixInsight, Lightroom
- Image by
- Lee Pullen
Exposure by filter
Optolong L-Quad Enhance
- Channels
- RGB
- Subframes
- 150 × 2 minutes
- Integration
- 5 hours
View subframe and stack
Single subframe and integrated stack, both with a simple stretch applied.
Kit list
This is the equipment I used to capture the image.
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Telescope: Askar 130PHQ
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Camera: ZWO ASI 2600MC Pro
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Mount: StellarDrive X 6R PRO
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Rebuilt into a StellarDrive X 6R PRO by DarkFrame Optics.
Askar M54 Off-Axis Guider
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ZWO ASI 220MM Mini
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Buy from Astroshop.eu
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Control: ASIAIR Plus
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Buy from High Point Scientific
Filter: Optolong L-Quad Enhance
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Buy from Astroshop.eu
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Seestar S50 image
Seestar S50 telescope photo of M3, also taken from my Bortle 8 city centre location.
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