Messier 33 The Triangulum Galaxy

Image Title: Messier 33 The Triangulum Galaxy

Copyright: S.M.G Astro

Date image was taken: November 28, 2025

Location: Mont-Saint-Michel Bay

Data Acquisition Method: Personal Telescope Setup

Description and Details: M33, or the Triangulum Galaxy, is one of the spiral galaxies closest to the Milky Way and one of the major members of the Local Group, which also includes the Milky Way and the Andromeda Galaxy (M31). Located about 3 million light-years away, it stands out for its relatively open and low-mass spiral structure compared to other large spiral galaxies.

With a diameter of about 60,000 light-years, M33 is smaller than the Milky Way but shows a high level of star formation activity, particularly in the gigantic region NGC 604, one of the largest known clouds of ionized gas. Its diffuse brightness and nearly face-on orientation make it easy to observe its spiral arms rich in nebulae and young star clusters.

Sometimes considered a distant satellite of Andromeda, M33 plays an essential role in the study of spiral galaxy evolution thanks to its proximity and relatively simple structure.

For this photo in HOO-RGB, I used two telescopes. I took 90 images of 8 minutes each in Hα and OIII with a 250 mm f/3 Newtonian, and 100 images of 2 minutes each in RGB with a Celestron RASA 8. The cameras used were ZWO ASI 533 MC Pro, all mounted on a Sky-Watcher EQ6-R Pro mount.

Name: Mathieu Geffroy

Website or Facebook Profile: http://www.youtube.com/@SMGAstro