Image 1: Triangulum Galaxy reprocessed 2024-12 by Calvin Klatt
The Triangulum Galaxy is one of our neighbours, with the Andromeda Galaxy, in the “Local Group”. It is a bit further than Andromeda and a bit smaller. The galaxy is at a good angle to us, not face-on but we can see the spiral arms very clearly. Being large and bright this Galaxy was important in astronomy history, in particular when Hubble realized that these spiral objects were truly island universes, far, far away from us. This galaxy is also close enough to us that we can see and study many individual red nebulae in it, just like the nebulae in the Milky Way galaxy.
This is #33 in Messier's list of objects that are not comets. It is found in the Triangulum constellation, in our Northern skies. Like the Andromeda Galaxy it derives its name from the constellation it is found in.
In the past few years we learned that the Milky Way and Andromeda Galaxies were headed for a collision in a few billion years. Well, it seems that the Triangulum Galaxy will very likely join in the fun, since it is loosely bound to Andromeda. You don’t want to be around for this three-way collision.
The galaxy was discovered by Giovanni Battista Hodierna on Sicily in 1654, long before Messier made his list of objects (1781). Hodierna developed a microscope from lenses and presumably built a crude telescope as well. His work was published but was very little known and he was never credited by the wider world for his discoveries. It is believed that Messier never heard of him and it was only in the late 20th century that the scientific world rediscovered Hodierna.
I have previously had good images of M33 but when I went to make a print recently I saw a bunch of flaws that I thought I could clean up. This image was produced in December 2024 from RGB data (colour camera) and Hydrogen-Alpha narrowband imagery collected in September 2022. The H-Alpha data was used to enhance the red nebulae in the galaxy. I tried to be subtle with the addition of H-Alpha data, unlike some people…
On Wikipedia the entry for M33 had an image that I found very similar to my own. It has better detail of the spiral arms and massive red blotches showing the nebulae/H-Alpha regions. This is shown in image 2. The telescope used was the “VST” with a primary mirror diameter of 2.65 meters located at the European Southern Observatory (ESO) Cerro Paranal Observatory, in Chile. Doing the math, 2.65 meters is 104”. My telescope aperture is 11”. Photons collected goes with the square, so 104*104=10816 versus 11*11=121. Esthetically I prefer my image, scientifically the ESO image is better.
Image 2, ESO image of Triangulum Galaxy.
Image Credit: By ESO - http://www.eso.org/public/images/eso1424a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=34571682
The Triangulum Galaxy is at a declination of plus 30 (positive is North), so it is nicely visible from Canada (Ottawa is at 45 N). It is nearby, as Galaxies go, so it appears quite bright and large (roughly a degree by half a degree). To pick up the smaller features it helps to have plenty of data: This image used 181 minutes of RGB imagery and 42 minutes of narrow-band H-Alpha. Much data has to be thrown away (satellite tracks, vibrations, cloud) so to have four hours of good data implies that at least five hours of imaging was done.
Of Distances:
The “local group” are nearby on the scale of the universe, but…
If you could travel at the speed of light you could go around the Earth 7 times in 1 second. You could travel to the Moon in 1.3 seconds and to the Sun in a little over 8 minutes. It would take you around 1,300 years to travel to the nearby Orion nebula here in the Milky Way galaxy. It would take you 2.7 million years to visit the Triangulum galaxy.
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