M20 – Trifid Nebula
The Trifid Nebula is a colorful combination of nebulae types that unite to create a celestial work of art. Cataloged as Messier 20, the Trifid Nebula is a magnitude +6.3 H II region of interstellar gas in the constellation Sagittarius.
M20 is an exquisite deep sky astrophotography target for amateur photographers, and worthy of extra attention through any telescope. The version below was taken at the 2018 Cherry Springs Star Party using an Explore Scientific ED140 apochromatic refractor telescope, and one-shot-color astronomy camera.
M20 – The Trifid Nebula in Sagittarius.
The Trifid Nebula was discovered by Charles Messier on June 5th, 1764, and number 20 of the 110 Messier objects in his catalog. Its name means “divided into three lobes”, as the dark nebula in this object creates the apparent “gaps” within the emission nebula portion of the Trifid.
Messier 20 includes a unique combination of an open cluster of stars, an emission nebula, a reflection nebula, and a dark nebula. All of these elements combine to create one of the most stunning deep sky objects in our night sky.
Trifid Nebula Details
- Designation: M20, NGC 6514, Sharpless 30
- Constellation: Sagittarius
- Type: Emission Nebula, Reflection Nebula, Dark Nebula, and Open Cluster
- Distance: 5,200 light years from Earth
- Size: 42 light years in diameter
- Apparent Dimensions: 28 arcminutes
- Visual Magnitude: 6.3
This star-forming region is an extremely popular choice for amateur astrophotographers in their backyard. The Trifid Nebula was the subject of the following video on my YouTube channel in August 2016.
I used a DSLR camera and a refractor telescope to photograph this nebula from my backyard. To create the final image, I combine several long exposure images together to create an image with an improved signal-to-noise ratio.
For a behind-the-scenes look at how I photographed the Trifid Nebula from my backyard using a camera and telescope, please watch the video below:
Through photography, we can truly enjoy the intense colors of the Trifid Nebula that are not possible to observe visually. A light pollution filter will help to separate this nebula from a washed out city sky.
The Trifid Nebula and M21 star cluster through a telescope.
How to find the Trifid Nebula
Through a telescope, the Trifid Nebula appears as a bright and peculiar object in a highly observed and photographed area of Sagittarius.
To find it, you will need to point your binoculars or telescope towards the Teapot asterism in the constellation Sagittarius. The shape of the celestial teapot is a recognized star pattern, but not an official constellation. The teapot shape should become obvious to your eyes once you know where to look.
From mid-northern latitudes, the Teapot lies due south, and is highest in the sky around midnight by early July. Because Sagittarius doesn’t rise very high in our northern sky, you may have to deal with trees or other obstructions that are blocking your view of the southern horizon.
The location of the teapot asterism in Sagittarius.
Star-hopping from the Teapot
As seen in the star chart above, you can use the stars on the right-hand side of the Teapot asterism to star-hop over to the Trifid Nebula. It may help if you draw an imaginary line form the bottom star in the spout, through the middle of the two stars above it.
You will likely notice the bright nebula known as the Lagoon Nebula first, but the Trifid is just above it. Needless to say, this portion of the Milky Way is an absolute pleasure to view through binoculars or a small telescope.
Here is a photo I snapped from my backyard in August 2015 that shows just how close the Trifid Nebula is to the Lagoon Nebula.
Find M20 in the Milky Way
The Sagittarius constellation is full of amazing deep sky objects, from globular star clusters to glowing emission nebulae. During the summer months in the northern hemisphere, it is where I spend the most time with my camera and telescope.
Sagittarius is one of the constellations of the zodiac, and lies between Scorpius and Ophiuchus in the night sky. The Trifid Nebula and Lagoon Nebula can often be clearly identified in wide-angle photographs of the Milky Way, as glowing pink patches near our galaxy core.
The location of the Trifid Nebula within the Milky Way.
Long exposure photographs of the Milky Way also highlight a number of other emission nebulae and star clusters near M20. The most noticeable ones include the Omega Nebula at the north end of Sagittarius, and the Eagle Nebula in Serpens.
M20 is certainly one of the most interesting objects in the constellation Sagittarius, but it is not the brightest. In fact there are many deep sky objects brighter than the Trifid Nebula in this star-rich constellation.
The brightest objects in Sagittarius:
- Messier 22 (Mag 4.6 Open Cluster)
- NGC 6530 (Mag 4.6 Open Cluster)
- Messier 22 (Mag 5.2 Globular Cluster)
- Messier 23 (Mag 5.5 Open Cluster)
- Messier 21 (Mag 5.9 Open Cluster)
- Messier 17 (Mag 6.0 Omega Nebula)
- Messier 20 (Mag 6.3 The Trifid Nebula)
- The Trifid Nebula in Infrared (APOD)
- The Constellation Sagittarius (In-the-sky.org)
- Amateur astrophotography image of the Trifid Nebula (Sky and Telescope)