M16

M16

Diffuse Nebula
NGC 6611
Serpens
18H 18.8m -13° 47'

Magnitude: 6.4
Size: 20'
Distance: 7,000 light-years

M16   

Suitable for beginners

Skill Level
M16 is a beautiful nebula easily accessible to beginners with basic equipment.

AugustBest Month
Summer is the ideal time to capture this object. Look for M16 in the southern skies during August.

Refractors
Newtonians
SCTs

Recommended Equipment
Though not as bright as M42, the Eagle Nebula can be captured with modest equipment.

A rich-field Newtonian allows you to capture the extended areas of the nebula while still showing the central detail.

An SCT can concentrate on the famous pillars at the center of the nebula—try to get as much resolution as you can. But use a focal reducer if you can't get enough exposure time.

A small refractor will show the whole nebula. Make sure you get a lot of exposure time.

Image

Image Stats
Meade 8" SN LXD75
Meade DSI Pro III
Meade RGB + IR filters

RGB at 94:54:70 minutes respectively. 2-minute subs.

Good transparency
26-27 June 2009
San Mateo, CA


The science of astronomy is hobbled by the fact we cannot (yet) visit most of the places we want to study. All we can do is study what we can see from afar. In Galileo's time, this meant putting your eye up to a telescope and recording what you saw, but since the invention of photography, astronomers have been studying the sky by taking pictures of it.

Making a virtue out of necessity, astronomers have become very good at taking pictures of the sky and of the amazing objects it contains. I have no doubt this emphasis on visual images—so much more visceral than the dry graphs, equations, and words of other sciences—is responsible for the general popularity of astronomy.

The Hubble Space Telescope picture of the core of M16, known as the "Pillars of Creation," is a perfect example. The massive columns of dust illuminated by brilliant stars look beautiful and awe-inspiring, even if you don't know they are star-forming factories more than a light-year tall. I had seen pictures of M16 before (pictures not unlike my amateur shot above) but it was not until I saw the Hubble photo that I felt like I was looking at a real place. You don't need a PhD in astrophysics to appreciate what you're seeing.

Sure, it would be nice if astronomers had more than pictures to study the universe. But until we discover faster-than-light travel, we'll have to settle for what we've got. Even then it may not help in the case of M16. In 2007, scientists taking pictures of M16 (this time with the Spitzer Space Telescope) raised the possibility that a supernova explosion has obliterated the famous pillars. The pillars appear intact to us on Earth because the light from the destruction has not yet reached us (and may not reach us for another 1,000 years).

If true, then pictures of M16 and its iconic pillars are even more special. They might be all we have left of it.

Imaging Notes

M16 is a large and bright target, suitable for all experience levels and equipment. Because the nebula emits red light from hydrogen you will find the best detail is in the red channel. If you are taking an LRGB image you should consider mixing some of the red channel into the luminance channel to increase the contrast and detail in the nebula. If you are taking an RGB image you could synthesize a luminance channel by combining the three color channels with a heavy emphasis on red. In the image above, I synthesized a luminance channel using a 3:1:1 ratio for red, green, and blue.

Pillars of Creation

Credit: J. Hester, P. Scowen (ASU), HST, NASA