Facts about and images of the beautiful spiral Triangulum Galaxy

Images of and facts about the iconic Triangulum Galaxy, M33.

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Published: March 11, 2024 at 11:38 am

The iconic Triangulum Galaxy, M33, is located 3 million lightyears from Earth in the Triangulum constellation, and is a fellow member of our Local Group of galaxies.

Measuring just 60,000 lightyears across the Triangulum Galaxy is the Local Group’s third largest galaxy.

That's compared to the 200,000 lightyear and 100,000 lightyear diameters of the Andromeda Galaxy and the Milky Way, respectively.

An image of the Triangulum Galaxy captured by the Hubble Space Telescope. Credit: NASA, ESA, and M. Durbin, J. Dalcanton, and B. F. Williams (University of Washington)
An image of the Triangulum Galaxy captured by the Hubble Space Telescope. Credit:NASA, ESA, and M. Durbin, J. Dalcanton, and B. F. Williams (University of Washington)

The Triangulum Galaxy's distinct spiral structure suggests it has existed largely unperturbed by gravitational interactions with other galaxies.

But astronomers believe that its proximity to our home galaxy means it could well be on a collision course, and may end up becoming a third party in the predicted Andromeda-Milky Way collision over 4 billion years from now.

For now, it is a stunning galactic specimen and one of the most famous galaxies in the Messier Catalogue.

It is also on our list of the best galaxies to observe in the night sky.

The Triangulum Galaxy, as seen by the Very Large Telescope. Credit: ESO
The Triangulum Galaxy, as seen by the Very Large Telescope. Credit: ESO

The Triangulum Galaxy's bright blue arms indicate the presence of scorching hot new young stars and that this is a galaxy undergoing rapid star formation: potentially a mass equivalent to that of our Sun being produced every two years.

Below are images of the Triangulum Galaxy captured by BBC Sky at Night Magazine readers and astrophotographers from around the world.

How to locate and observe the Triangulum Galaxy.

A chart showing the location of the Triangulum constellation and the Triangulum Galaxy in the night sky.
Use the Great Square of Pegasus or the Andromeda Galaxy to help you find the Triangulum constellation and the Triangulum Galaxy.

If you want to find and observe the Triangulum Galaxy through your telescope, you'll need to find the Triangulum constellation first.

You can use the chart above to help you.

The Triangulum Galaxy is listed at mag. 5.7, but it can be a tricky target to see as its surface brightness is quite low.

To find the Triangulum Galaxy, extend a line from M31, the Andromeda Galaxy, through star Mirach for the same distance again.

A small telescope under dark skies will show the galaxy's core as a misty smudge.

A 250mm scope shows a mottled patchwork of dim light surrounding the core.

For more information about photographing galaxies, read our guides to deep-sky astrophotography and deep-sky image processing.

And don’t forget to send us your images or share them with us via Facebook, Twitter and Instagram.

Gallery: Images of the Triangulum Galaxy

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