The Orion Nebula
The Orion Nebula is one of the brightest nebulae in the night sky and is visible to the naked eye. This magnitude 4 interstellar cloud of ionized atomic hydrogen contains a young open cluster of four primary stars known as the Trapezium.
The M42 nebula is part of a much larger nebula system known as the Orion Molecular Complex, which extends throughout the Orion constellation including objects such as the Horsehead Nebula, M78, and Barnard’s Loop.
The Orion Nebula itself extends across a 1° region of the night sky. It includes associations of stars, ionized gas, and areas of reflection nebulae. When photographing the Orion Nebula, it is common to include the nearby Running Man Nebula (NGC 1977) in the same frame as shown below.
The Orion Nebula captured with my camera and telescope in the backyard.
The mighty Orion Nebula is arguably the most spectacular deep-sky object in the night sky. I sincerely hope that you have the privilege of observing M42 (Messier 42) through a telescope at some point during your life. You will never forget it.
Unlike many of the dim nebulae regions in the sky, this one is bright and rewarding when observed through the telescope eyepiece or binoculars. The bright core of the nebula is easy to spot, even from a heavily light-polluted location.
In terms of astrophotography, it is one of the most gratifying deep-sky objects you could ever photograph through a telescope (or a camera lens). The rich glowing emission gas and reflected starlight of the Orion Nebula embody the breathtaking beauty of our Universe.
Orion Nebula Overview
The Orion Nebula is a bright diffuse nebula, which includes a range of nebula types including emission nebula, reflection nebulae, and dark nebulae. Its location in the night sky makes it possible to observe from both hemispheres.
- Object Type: Reflection Nebula/Emission Nebula
- Designations: Messier 42, M42 NGC 1976, Sharpless 281
- Common Name: The Orion Nebula, The Great Orion Nebula
- Constellation: Orion
- Distance: 1,344 light-years
- Size: 24 light-years across (1°)
- Apparent Magnitude: +4.0
- Apparent Dimensions: 65 × 60 arcmins
The Orion Nebula is so bright, that it is possible to observe it with the naked eye. With an apparent magnitude of +4, this glowing emission nebula/reflection nebula can even be enjoyed from locations with moderate light pollution.
You’ll find Messier 42 in the “Sword” of the Orion constellation, which are the 3 stars located south of Orion’s Belt. It may look like just another “star” at first, but a closer look (even without the aid of binoculars) will reveal a fuzzy patch.
Related Post: Tips for Viewing the Orion Nebula
This diffuse nebula is estimated to be about 24 light-years across and is the closest region of active star formation to Earth. If you are wondering what the Orion Nebula looks like through a telescope, some have described it as “a star encased in a globe of luminous fog“, and that’s about as good a description as I have ever heard.
In the following video from NASA, you will take a flight through the Orion Nebula in visible and infrared light. By combining the infrared capabilities of the Spitzer space telescope with Hubble’s visible light, we can enjoy a multi-wavelength visualization of the Orion Nebula.
Flight Through the Orion Nebula in Visible and Infrared Light. (NASA Video).
How to Find the Orion Nebula
Orion is one of the easiest constellations to identify in the night sky. “The Hunter” formation of stars is unmistakable, even from the city. Orion’s Belt is the most striking feature of the formation, 3 bright stars in a row that create an imperfect line. The intensely red star at the upper left of Orion should also stand out. Betelgeuse is a red supergiant and one of the largest stars visible to the naked eye.
On the bottom right of this star formation, is yet another extremely bright star, but this one shines blue-white. Rigel is the brightest star in the Orion constellation, and approximately 40,000 times brighter than our sun. The star factory affectionately known as the Orion Nebula can be found North of Rigel, in Orion’s Sword. Have a look at the star charts below for reference.
The seven primary stars that make up the distinctive hourglass-shaped asterism of Orion the Hunter are Rigel, Betelgeuse, Bellatrix, Saiph, Alnitak, Alnilam, and Mintaka. Nearby Canis Major is said to be Orion’s faithful dog. The brightest star in Earth’s night sky, Sirius, represents the nose of the dog.
Because Orion’s Belt is so bright and identifiable, you should be able to spot the Orion Nebula just below them. The star charts above depict the view from the northern hemisphere, if you are in the southern hemisphere the constellation appears upside-down.
When to See The Orion Nebula
The best time to see the Orion Nebula is January when it is visible almost all night long. Orion is a winter constellation (in the northern hemisphere), that many associate with cold, crisp nights.
From the northern hemisphere, Orion is due South and highest in the night sky at about midnight in December. In the southern hemisphere, it appears in the northern sky at this time.
As the winter months pass, Orion will rise about 2 hours earlier each month. January and February are the best time to see and photograph the Orion Nebula. By late March, the constellation Orion fades into the western horizon soon after dark.
The Orion Constellation is easy to identify in the night sky. Look for the Orion Nebula in the ‘sword’ of Orion.
The Orion Nebula was the first deep sky object I ever witnessed in color through photography. I used a point-and-shoot digital camera to image through the eyepiece of my Dobsonian Telescope in 2010.
The result was a blurry smudge of purple light, and that was enough to spark my interest to the level it’s at today. My early experiences photographing the Orion Nebula catalyzed a future lifelong obsession with astrophotography, and the night sky itself.
Through a Telescope or Binoculars
If you’re lucky enough to own a telescope, aim it below the 3 belt stars of Orion towards his sword. Use your telescope’s finder scope to identify the fuzzy patch that sits between the three stars of Orion’s sword, and then hop back on the eyepiece for a wondrous sight.
With enough aperture and good seeing, you should be able to spot the Trapezium cluster near the core of Orion. The Trapezium Cluster is a young open cluster with a diameter of about 1.5 light years. Look for a tightly packed collection of 4 stars using a high magnification eyepiece for the best results.
Unlike many of the faint deep sky nebulae in the night sky, the bright Orion Nebula offers an impressive view for backyard stargazers in the city. I often take a look at M42 using a pair of 15 x 75 binoculars. I highly suggest observing Orion this way if you haven’t before, as it creates a real-time observing experience that gives you a “lost in space” feeling.
Use a Dobsonian Telescope with at least 8 inches of aperture for an impressive view through the telescope eyepiece.
Astrophotography Tips
Over the years, I have photographed Orion using countless cameras, telescopes, and camera lenses. The fact that it is one of the brightest nebulae in the night sky, makes it a fantastic beginner astrophotography target.
You can capture a simple photo of the Orion Nebula using a DSLR camera and tripod (or even your phone), without a tracking mount. However, the nebula will begin to blur in exposures of as little as 5 seconds due to the rotation of the earth.
By using an equatorial tracking mount or star tracker (shown below), you can freeze the nebula in place for a long exposure image. The use of a telescope or a telephoto lens will provide a deeper view of the Orion Nebula like the images shared on this page.
A portable star tracker and camera lens are capable of incredible images of the Orion Nebula.
The amount of overall exposure time and the types of filters that were used can change the type of image you create dramatically. In the world of astrophotography, the more signal (light) you can collect, the better.
With a tracking mount that has been properly polar aligned with the celestial pole, you should be able to capture sharp sub-exposures of 60 seconds or more at almost any focal length. To improve the tracking of your mount for longer exposures, you can add an autoguiding system to your rig.
As you learn better image acquisition techniques and image processing skills, your image of M42 will become more and more beautiful over time. A typical tracked image of the Orion Nebula will include anywhere from 30 minutes to 10 hours of total exposure time.
Amateur photographers will often include the Running Man Nebula (NGC 1977) in their image of the Orion Nebula as it is close by and compliments the final presentation of the image. For reference, a focal length of about 400-600mm will reveal both Messier 42 and NGC 1977 in the same frame.
The Orion Nebula captured with a dedicated astronomy camera and LRGB filters.
The image above was captured from my backyard, suburban sky (Bortle 6) using a monochrome astronomy camera and individual LRGB filters. While this advanced method of image acquisition is beneficial, it is possible to capture a beautiful image of Orion with a simple light pollution filter.
For example, the image below was captured using a Canon RF 70-200mm F/2.8 lens and a DSLR camera. A broadband light pollution filter (Optolong L-Pro) was used to reduce the glow of my city sky while allowing the natural colors of this object and stars to shine through.
The Orion Nebula using a DSLR camera and telephoto lens from the city.
Which Telescope to Use for Astrophotography
The size of the Orion Nebula is well suited for many focal lengths, be it a telephoto lens or astrophotography telescope. The wide field of view offered by a compact refractor telescope will allow you to capture the entire M42 nebula, along with M43, NGC 1977, and many more interesting cataloged objects in this area.
For an example of the types of telescopes I have used to photograph this object from my backyard, have a look at my extensive list of best astrophotography telescopes. Because this object is so bright, almost any telescope is capable of delivering impressive views of Orion.
You can use a software tool like Stellarium, or your favorite stargazing app to help you plan for a night of astrophotography or observing. Because Orion is in the northern hemisphere sky in the winter, I have to plan my imaging sessions well in advance to be ready for a rare clear night.
The best time to photograph Orion through your telescope is during the new moon phase, as this will allow you to capture images without a bright moon interfering. It is also wise to photograph this object (or any deep-sky object) on a night with great seeing conditions, especially when using longer focal lengths.
The images you take are often clearest when the constellation is highest in apparent altitude in the sky because there is less atmospheric disturbance in the air. The apparent altitude in the sky that Orion will reach depends on your geographical location and the time of year.
Dealing with the Bright Core
Orion can also be difficult to capture properly because of the dramatic contrast in brightness between the faint outer regions, and its luminous core. Astrophotographers will usually capture at least 2 sets of exposures at different lengths to reveal the darkest and brightest regions evenly.
In the graphic below, you’ll notice the image on the left is much dimmer overall, but it doesn’t overexpose the bright core of the nebula. The image on the right includes much more of the surrounding details, but now the brightest area of the core is ‘blown out’.
The solution to this problem is to create two different ‘stacks’ (integrations) of sub-exposures. One with short exposures (10-10 seconds or shorter), and one with longer exposures (60 seconds or more).
Capturing an Orion Nebula with a High Dynamic Range requires at least two sets of exposure lengths.
Camera Settings and Advice
A typical imaging session on M42 and the surrounding area will involve photographing several long-exposure images that can later be registered and stacked to produce a final image with a healthy signal-to-noise ratio. I use a free software called DeepSkyStacker to pre-process all of my astrophotography images.
Here are some recommended DSLR camera settings for the Orion Nebula through a telescope on a tracking mount:
- Mode: Manual (Bulb)
- ISO: 800-1600
- Exposure: 2-3 Minutes
- White Balance: Daylight
If you are using a camera lens, set the lens’ f-ratio low (F/4 or below). The sharpness of the stars in your image will vary lens by lens, but in general, you want the lens to gather as much light as possible in a single shot. Fast lenses such as F/1.8 may benefit from stopping down to F/2.8 or F/3.2 for easier focus and a sharper image.
The bright core of the Orion Nebula may clip the highlight data in your image in exposures as short as 15 seconds. To create images of the Orion Nebula with a high dynamic range (HDR), photographers often capture short exposures of 5-10 seconds to capture the fine details near the Trapezium. These details can then be blended into the long exposure shots for a dramatic image.
The Orion Nebula and Horsehead Nebula region photographed in a single frame.
Image Processing
Image processing is a completely different aspect of astrophotography from image acquisition. The Orion Nebula is an excellent test subject to practice your image processing skills on. For a detailed step-by-step image processing tutorial, you can follow along with the steps I take in Adobe Photoshop in the following post:
Deep Sky Image Processing Tutorial – Orion Nebula
I have also created another tutorial that explains how to fix the bright core of Orion in Adobe Photoshop. To accomplish this, you can blend in a photo of the Orion Nebula captured using a shorter exposure length. By blending a shorter exposure image of the bright core, you can create an HDR version of Orion with more detail overall.
Wide Angle Camera Lens
In a post I made about using a camera lens for astrophotography, I collected light on Messier 42 and the surrounding area. This included interesting deep-sky objects like the Horsehead Nebula, Flame Nebula, and Barnard’s Loop.
Even at this focal length (105mm), the Orion Nebula is an incredible sight. The photo below was captured using a Canon Rebel DSLR on an iOptron SkyTracker Pro camera mount, a popular star tracker for amateur astrophotographers.
Several exposures in true-color RGB were stacked together to improve the signal-to-noise ratio of the final image. Narrowband H-Alpha data was also added to bring increase the intense glowing gas from these nebulae even more.
Images of the Orion Nebula using various astrophotography equipment:
Orion Nebula and Running Man Nebula using a Canon EF 300mm F/4L Lens
Helpful Resources:
- Hidden Secrets of Orion’s Clouds (European Southern Observatory)
- A Peak Inside the Orion Nebula (NASA)
- Celestial Cloudscape in the Orion Nebula