YM-16 is a planetary nebula in Serpens. It is Mag 14.4, about 6 Ly in diameter  and 2900 Ly distant.
North is up

23 hours total HaRGB, August 2011

Planewave CDK 12.5", STL11K, Astrodon Gen II filters, AP1200 mount
Capture with Maxim and CCDCommander
Processing with CCDStack and Photoshop

Click on image for full size (1 Mb)

Thanks to:

Anthony Ayiomamitis for demonstrating there are interesting targets out there, off the beaten path

Bob Franke for ezSkyView which let me see which of those obscure targets would work with  my filters and framing
Yerkes-McDonald 16
(AKA RCW 181 AKA PK  038.7+01.9)