Astronomy Picture of the Day - Messier 33: The Triangulum Galaxy

NASA ^ | 18 Sep, 2026 | Image Credit & Copyright: George Chatzifrantzis

[MtnClimber]

Explanation: The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, Messier 33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from the Milky Way, this sharp telescopic image shows off M33's blue star clusters and pinkish star forming regions along the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 5 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.

---

TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; nasa

[MtnClimber]

To be added or removed from the Astronomy Picture of the Day ping list please send me a request via "Private Reply" (Mail).

For more detail go to the link and click on the image for a high definition image. You can then move the magnifying glass cursor then click to zoom in and click again to zoom out. When zoomed in you can scan by moving the side bars on the bottom and right side of the image.

[MtnClimber]

[MtnClimber]

Pinging the APOD list

🪐 🌟 🌌 🍔

[ComputerGuy]

There is much awesomeness out there.

[Army Air Corps]

I can see Uncle Zlort’s house!

[No name given]

Wow.

[No name given]

That’s the truth.

[AZJeep]

This is the closest large galaxy to us. Closer then the Andromeda galaxy.
It could be seen by naked eye under very good observing conditions, but it is actually quite hard to locate even with scope.
Since it is close and face on, it covers very large area of the sky, so scopes often just look through it without noticing it.

[NavyShoe]

The scale is beyond comprehension.

[SkyDancer]

Cool stuff. Thanks.

[econjack]

At one time, I was so fascinated by the universe that I wanted to be an astronomer. Then, someone discovered that the universe was continually expanding and when I asked: “Expanding into what?”, no one had an answer. That’s when I switched to economics.

[MortMan]

I don’t see the triangulum! (LOL)

[No name given]

I second that.

[telescope115]

My fellow amateur astronomers and I used to frequent a forest preserve north of town. I could see M33 easier with binoculars than with a scope. It was faint, but it was there. We didn’t have telescopes big enough to make out H2 regions, but the people doing astrophotography (with film) had no problem.

We were forced to move to a quarry a little further away, the locals thought we were devil worshippers, out there in the middle of the night. Amazing….