The Winter Triangle, also known as the Great Southern Triangle, is a collection of some of the brightest stars in the winter sky and includes Sirius, Betelgeuse, and Procyon.
These three stars make up the vertices of the imaginary equilateral triangle forming the Winter triangle and are also the primary stars in three separate constellations: Canis Minor, Orion, and Canis Major.
Sirius and Procyon also make up part of the Winter Hexagon (or Winter Circle) which includes seven prominent stars (Sirius, Procyon, Castor and Pollux, Capella, Aldebaran, and Rigel), with Betelgeuse at the center.
The Winter Triangle is a pattern or group of stars (i.e. an asterism) that requires the visual observer to mentally connect the lines and is not a formally-named constellation.
Although the distinction between an asterism and constellation remains inconsistent depending on the source, in most cases, an asterism is considered an informal group of stars.
What stars are in the Winter Triangle?
The three stars that form the Winter Triangle are among the brightest in the sky, which makes them easy to find.
Betelgeuse, the left shoulder of Orion, is the bright red star above the easternmost star of the Belt. Sirius can be found by drawing a line through Orion’s Belt and Procyon is to the upper left of Sirius.
The Winter Triangle. Messenger Mountain News
- Constellation: Canis Major
- Magnitude: -1.46
- Distance: 8.6 light-years
- Constellation: Canis Minor
- Magnitude: 0.34
- Distance: 11.5 light-years
- Constellation: Orion
- Magnitude: 0.50
- Distance: 640 light-years
Video: The Winter Triangle
In the following video, the presenter describes how to find the Winter Triangle asterism in the night sky using the star Sirius as a reference.
Sirius is the brightest star visible in the night sky from any part of Earth and is sometimes called the Dog Star due to its location in the constellation Canis Major (i.e. the Greater Dog).
It is an ‘A’ type binary star and appears so bright because it is one of the nearest bright stars to Earth at only 8.6 light-years (second only to the sun).
Due to its brightness, it has been known to ‘flicker’ with many colors, however, these changes in color are a result of the star shining through Earth’s atmosphere.
Procyon is the eighth brightest star in the sky and the brightest star in Canis Minor, known as the Little Dog Star. Like Sirius, this star is close to Earth at 11.5 light-years, making it the 16th nearest star to Earth.
Procyon is considered to be evolving from a normal mature star and will eventually become a red giant star.
The name Procyon is Greek which means ‘before the dog’ signifying the rise of this star shortly before Sirius, which was particularly important in ancient Egypt.
Today, at some latitudes, Sirius now rises before Procyon due to changes in the Earth’s motion.
Betelgeuse is another bright, luminous star (10th brightest) and is visible to everyone (except at latitudes south of 82 degrees) between mid-September to mid-March, with the best observations in mid-December.
Unlike Sirius though, Betelgeuse is nowhere near our solar system at 640 light-years away from Earth.
When can you see the Winter Triangle?
The Winter Triangle is high in the sky at mid-northern latitudes for the majority of the winter season. From the southern hemisphere, it appears upside down and lower in the sky in the summer months.
It is useful for locating the winter portion of the Milky Way, visible to the left of Betelgeuse and Sirius and right of Procyon extending through the larger Winter Hexagon.
The Winter Triangle can also be helpful for finding the following deep-sky objects:
- Heart-Shaped Cluster (Merrier 50)
- The Cone Nebula
- The Christmas Tree Cluster (NGC 2264) in Monoceros
- Messier 41
- Tau Canis Majoris Cluster (NGC 2362)
- Caroline’s Cluster (NGC 2360) in Canis Major
Photographing the Winter Triangle
Photographing the Winter Triangle will require a wide-angle camera lens with a focal length of 24mm or shorter. A full-frame camera sensor will allow you to utilize the native focal length of your camera lens, while a crop-sensor will tighten the field of view by a factor of 1.6X.
A camera lens I recommend for nightscape photography is the Sigma 24mm F/1.4 Art Series. This lens captures sharp images and is great in low-light situations. I’ve used the lens on my Canon DSLR and Mirrorless cameras (Canon EOS Ra), and have found it to be one of the most useful lenses I own.
A star tracker will allow you to capture long exposure images of the Winter Triangle, and potentially pick up some faint deep-sky objects in the area as well. The star tracker will need to be polar aligned with Earth’s celestial pole to accurately track the apparent movement of the night sky over a long period of time.
Use a star tracker with your camera and wide-angle lens to capture a detailed scene.
Sometimes, a thin layer of clouds or fog can make a constellation photo more dramatic. A thin layer of moisture in the air will often make the brightest stars in the field appear bigger in a long exposure image. This is useful when photographing asterisms and constellations in the night sky.
You can always boost the brightness of the stars in the Winter Triangle in Adobe Photoshop to help illustrate the scene. One of the best ways to do this is to carefully select each star you wish to enhance and copy a new layer on top of your original image.
Then, you can add a slight blur to the star layer, and apply this layer on top of the original at 25%-50%. You may want to increase the brightness of this blurred layer as well.
This has a way of introducing a subtle “glow” to the important stars, and better highlights your subject.
Winter constellations are constellations that are best observed during the winter months, particularly from late December to late March here in the northern hemisphere and late June to late September in the southern hemisphere.
The following is a list of northern winter constellations: