Collarbone Nebula (NGC 2022) in Orion
The tiny Planetary Nebula in Orion, NGC 2022, is listed as Stephan O’Meara’s Deep Secret
25th object (SD 25).  He calls it the Kissing Crescents Nebula, but since Hubble’s
photographs of it have become available, people have started calling it the Collarbone
Nebula.  The new Interstellarum Deep Sky Atlas (in my view the best field-usable,
hard-bound paper, celestial atlas currently on the market) also calls it the Collarbone Nebula,
so that is the common name I used.  Since it is so small (22 by 17 arcseconds) it will, under
low power appear star-like.  Under magnifications over 150x the disk becomes apparent and
was surprisingly easy to see from my suburban observing site with the 6.1” telescope.  Had I
not read O’Meara’s account of it in his Deep Secret book, before observing NGC 2022, I
would likely have missed that you can detect the nebula as an annulus.  With a little effort, I
could make it out, but it is subtle and thus represented as such in the drawing.  It is always
good to have an observational goal to look for when viewing a deep sky object.