The Orion Nebula, also known as M42, is a beautiful deep-sky object in the constellation Orion. While most nebulae (interstellar gas and dust clouds) are difficult or impossible to see with the naked eye, M42 is fairly easy to detect in the night sky for much of the year. With a little orientation, you will be able to see the Orion Nebula with your eyes, binoculars, or telescope.
Steps
Method 1 of 3: Locate the Orion Nebula using other stars
Step 1. Wait for the right time of year
Due to the slow orbit of the Earth around the sun, the nebula is not visible all year round. The nebula is visible from late fall to early spring. The constellation Orion, which contains the Orion Nebula, is highest in the sky around midnight in mid-December.
Step 2. Look for the nebula on the right side of the sky
Due to the spherical nature of the Earth, the direction in which the nebula will appear is relative to your position on our planet. In the northern hemisphere, look to the southwest. In the southern hemisphere, look northwest.
Step 3. Identify the best latitude to view the Orion Nebula
The nebula is best seen from latitudes of 85 and -75 degrees. In other words, if you hang out with polar bears at the North Pole, or with penguins at the South Pole, you won't see the Orion Nebula.
You can identify in which hemisphere you are looking at a map. If the country you are in is south of the equator, you are in the southern hemisphere. If the country you are in is north of the equator, you are in the northern hemisphere
Step 4. Find Orion's belt
Orion's belt is one of the most recognizable asterisms (group of stars in an identifiable cluster). It is composed of three very bright stars (Alnitak, Alnilam and Mintaka) aligned, relatively equidistant from each other. The Orion Belt and Nebula lie within the constellation Orion, so knowing where Orion is located will help you know that you are in the nebula's neighborhood.
Step 5. Find Betelgeuse and Rigel
If you imagine the Orion belt as perfectly parallel to your line of sight, and therefore forming a vertical line, Betelgeuse and Rigel are the two stars that sit on either side of the Orion belt. The path from Betelgeuse through Alnilam (the star in the middle of the belt) and to Rigel forms an almost straight line. Rigel and Betelgeuse are almost equidistant from Alnilam.
- Betelgeuse is a red supergiant and, true to its name, it glows a dull orange-red. It is located above and to the left of the Orion belt, if you are in the northern hemisphere, and below and to the right of the belt, if you are in the southern hemisphere.
- Rigel is a blue and white star located below and to the right of the Orion belt, if you are in the northern hemisphere, and above and to the left, if you are in the southern hemisphere.
Step 6. Identify the Orion Nebula
The Orion Nebula sits just off the line between Rigel and Alnilam, the central star in Orion's belt. The nebula is a faint, fuzzy blue patch on the sword of Orion, an asterisk composed of Iota Orionis (just below the Orion Nebula, when viewed from the Northern Hemisphere), the Orion Nebula, and NGC 1981 (a star cluster open visible just below the Orion Nebula, if viewed from the Northern Hemisphere).
Method 2 of 3: Use a Star Map to Find the Nebula
Step 1. Orient yourself according to the directions on the map
In other words, hold the star chart in such a way that the compass directions are aligned in the same way as your body. For example, if you are facing south (as you should to view the M42), hold the star chart so that the southern edge of the map is at the bottom and the north edge is at the top. Make sure the star map is for the current season.
Step 2. Identify nearby stars and constellations
Unless you have an exquisitely detailed star map, the Orion Nebula will not be explicitly labeled, although it should appear as a dot on the map. However, using the star map to locate nearby objects in the night sky will help you find it.
- The Orion Nebula is located just to one side of the line between Alnilam (the central star of Orion's belt) and Rigel, in the constellation Orion. These and other important features of the night sky will provide a relative guide to where you can locate it.
- There are several important stars and constellations around M42 that can help you locate it. Orion's belt is one of those constellations. Locating it with the star map should be easy.
- The constellation Orion is a major constellation and gives the Orion Nebula its name. Orion is at the intersection of Taurus, Lepus, and Gemini.
Step 3. Raise the star map over your head
The star map will reflect the appearance of the night sky. Think of it as an astronomical map. With the map in an elevated position, you can easily identify the various stellar objects in the sky quadrant. Find the stellar objects you identified as close to M42, then use their relative position to find it.
If the star map has a label for the M42, the job is much easier. Use it to locate the nebula
Method 3 of 3: Use Celestial Coordinates to Locate the Orion Nebula
Step 1. Identify the correct ascension for the nebula
The right ascension of a celestial object is the astronomical equivalent of longitude, and measures the distance eastward, from the celestial equator, towards the vernal equinox (the point at which the celestial equator and the ecliptic intersect during spring in the northern hemisphere). The correct ascension of the Orion Nebula is five hours. In other words, the nebula will cross the celestial meridian (the point directly above you or an observer) five hours after the vernal equinox.
Step 2. Identify the declination of the nebula
Declination is an astronomical equivalent to latitude and provides a guide to a point on the celestial sphere (the visible "sphere" of stars and astronomical objects that surround the Earth). Declination is measured relative to the celestial equator (the line you would get if the equator were projected into space). The declination of the Orion Nebula is five degrees. In other words, it is located along a plane, five degrees above the celestial equator.
Step 3. Prepare the telescope to locate the nebula
First, you will need to adjust the placement of the telescope so that it is "in station", parallel to the axis of the Earth. An in-station telescope would draw a direct line to the equator if the earth were flat.
Use the fit circle to find the nebula. You can designate the correct declination and ascension mechanically or, more recently, digitally. Look through the eyepiece to see the M42
Advice
- Wait about 20 minutes for your eyes to prepare to see in the dark.
- Try using binoculars or a telescope to look at the nebula.
- Viewing the M42 is best accomplished on a dark, clear night from October to March.
- The largest stars on the star map are the most visible and brightest. Use them to guide you.