M16 & M17 Narrowband
M16 (The Eagle Nebula) and M17 (The Swan Nebula) are quite often imaged alone. However, we sometimes forget how close these two are optically and they may be part of a larger complex of interstellar matter. Indeed in my image there appears to be a physical connection between these two nebula.

Personally I was a bit surprised by the brightness difference of these two objects - with the Swan being much brighter than the Eagle. (This is not as apparent in the final image due to the processing choices I made.)

Image taken using the facilities of JMSM Observatory.

Click the image above for larger versions of this image. Read the rest of this blog entry for some more details.


This image was acquired using three narrowband filters, capturing photons of light emitted from three different sources, singly-ionized sulfur or [SII] @ 672.4 nm (assigned to red), Hydrogen-alpha or Ha @ 656.3nm (assigned to green), and doubly-ionized oxygen or [OIII] @ 500.7nm (assigned to blue).

There were two issues I had in processing this image.

The first was related to the [SII] data. The nebula were all very dim in this filter. But in order to produce a pleasing image, I had to make the [SII] data much brighter than was originally recorded by the camera (a common processing choice when working with narrowband data). For this image, this produced good looking nebula but also many many red stars throughout the image. I toned these red stars back using the minimum filter in Photoshop to produce a more pleasing view.

The second issue was that I simply did not get enough exposure time for this image. Fortunately I was able to get this data during a break in the summer storms in New Mexico, but I was provided only one night of clear skies. The thunder clouds have moved back into the area and will be there for at least the next few days. So I did my best with the data I had.

This is my first posting after about two months of nothing. I have more data from the past couple months that I need to process, but just haven't had the time to finish up...

Thanks for looking!
-Matt