The Ring Nebula (M57) - Feb / JUNE
In this section you will learn where to find the Ring Nebula.
When to See The Ring Nebula
This Ring Nebula is best seen in the following months at the following times:
- February, between 5am and 7am
- March, between 3am and 5am
- April, between 1am and 3am
- May, between 11pm and 1am
- June, between 9pm and 11pm
M57 - The Ring Nebula
Anyone that's enjoyed astronomy for even a short period of time has encountered a picture of the Ring Nebula. It's such an iconic sight that its picture is used frequently in magazines and books on the subject.
If you're not sure whether you've come across it before or not, then take a look at the Hubble picture below (source), which shows it in all of its colorful glory:
The Ring Nebula
At magnitude 8.8, this is a bright planetary nebula around 2,300 light years away from us. As you'll see shortly, it is also conveniently positioned in the night sky to make it a good target for beginner telescope users.
Planetary nebulae, like this one and the Dumbbell Nebula, M27, are formed when a red giant star explodes off its outer layers. Those outer layers become the colorful ring you can see above.
What's left is a white dwarf star in the center. You can see the one at the heart of the Ring Nebula in the center of the blue circle, above. Unfortunately, that star shines fainter than magnitude 14 and is beyond the reach of our backyard telescopes, unlike the bright shell of nebulosity that it lights up.
The explosion that created M57 is believed to have happened around 4000 years ago and is still being felt - the nebula grows around 1 arcsecond every hundred years. That sounds painfully slow but actually means the gas ring is growing at the rate of 20 to 30 meters every second!
Where to Find The Ring Nebula
This is a summertime hunt which begins with the second brightest star in the northern celestial hemisphere: magnitude zero Vega, in the constellation of Lyra.
Lyra is a small constellation and, in mid June, you can see it almost due east around 35° above the horizon. Note the position of the north celestial pole (NCP) in the pictures below to help you locate it. As always the first image includes the imaginary lines of the constellations whereas the second does not. All stars are magnitude 4 or brighter.
Where to Find Vega, in Lyra, With and Without Constellation Lines
Images Courtesy of SkySafari Pro - www.SkySafariAstronomy.com.
Now you know where to find Lyra and its unmistakable brightness, let's zoom in and locate M57.
Star Hopping to The Ring Nebula from Vega
I have cheated a little in the picture below and increased the magnitude limit on the stars to 4.5 from the usual 4.0, this is so you can see all the stars which make up the stretched diamond box of Lyra.
The faintest two stars (ringed in the picture) both shine at magnitude 4.3 and are easily naked eye visible in most skies. You don't actually need these two to find M57, but I thought it would be helpful to include them to help you be sure you've found the right constellation.
Location of The Ring Nebula in Lyra
In the following picture I've added finderscope rings - blue for a magnifying finderscope and red for Telrad. You can see that the bright stars Sheliak and Sulafat both fit easily within the same view and that M57 is just off an imaginary line joining the two.
This a small and faint constellation which is easier to find in a darker sky. However, when you have it in your sights you can fit both Sheliak and Sulafat inside the same eyepiece view at a low magnification.
Your hunt for the Ring Nebula is easier if you can see the magnitude 5.2 star HR 7162 near Sulafat (highlighted on the picture below), because M57 is midway between Sheliak and HR 7162. However, this is not an easy star to see in a polluted sky and is not essential to finding M57, I have found the Ring Nebula by going straight to a low magnification eyepiece and pointing my scope in the right area between Sheliak and Sulafat.
Finding M57 With HR 7162
Images Courtesy of SkySafari Pro - www.SkySafariAstronomy.com.
If you start with a low magnification eyepiece (one with a longer focal length) you should pick up the planetary nebula fairly quickly, it looks like a hazy disc, but don't be discouraged if you don't see it straight away.
A large field of view with low magnification is a double-edged sword. On the plus side, it means you will definitely have the nebula in your eyepiece if you can see Sulafat and Sheliak in there. The minus side is that the nebula will be very small, so small in fact that it could take some finding if you are not used to seeing nebulae.
For me they are a bit like ghosts. When you look directly at them they seem to disappear but, glance off to the side, and they magically come into view in your peripheral vision.
Don't pressure yourself, take time to examine the field of stars, making sure to keep Sulafat and Sheliak in your view.
You are going to see dozens of tiny pinpricks of light, looking almost identical to each other. Finding the Ring Nebula is a bit like a stellar version of 'Where's Waldo?'. After a while of getting used to the view, eventually something will catch your eye that is not quite right, it is different from all the other points of light coming from stars in your field of view.
It may take you a moment or two to pin it down, but if you have the sensation that the something you just saw is it... then it probably is.
Seeing M57, The Ring Nebula
Now you've found it, does it look smaller than you expected it to? Almost certainly it does, but, even in a small telescope, it is bright enough to be a discernable - if hazy - disc shape.
When you have it centered in your wide field of view, swap in a higher magnifications to tease out variation in brightness between the middle and the outer edge. You'll be surprised at the level of magnification this nebula can take on a decent night.
Push it and use averted vision and you will see that the outer is brighter than the inner. The fact that this is a ring will become unmistakable, even if you suffer the frustration of feeling like you can't quite bring it into focus - which is quite normal. I can spend a long time on this object, tweaking focus and moving back and forth between magnification to tease out more details.
If you own a larger telescope you will have no trouble seeing the ring shape under a medium to high magnification.
It's a small, bright and distinctive nebula that takes some tracking down. However, when you have made that effort and been successful, I have no doubt you will be awestruck when you see it!
If you loved seeing this planetary nebula, then wait to you find next month's bigger and brighter Dumbbell Nebula!