NGC 2440
For telescopes 6" or larger
This image was obtained with the Hubble Space
Telescope. Don't expect it to look anything like this in the telescope!
At the center lies a newly formed, 17.5 magnitude white dwarf star--the
now bare core of the original star after puffing its outer layers away
to create the nebula.
I think the planetary nebula NGC 2440 (NGC 2440, PNG 234.8+02.4,
PK 234+02.1, ARO 47, ESO 560-9) is one of the finest in the sky. Catalogs
list it as a 10.8 magnitude object a mere 16" in diameter. Like many
planetary nebulae, in small telescopes or at low magnification it appears
as a small, elongated blob. Hunting it down and finding it in such instruments
is a reward in itself. In larger instruments some of the detail in the
above image begins to appear, making this a fine visual object.
This image from the DSS shows a 20' x 20'
field around NGC 2440. North is down and east is to the right.
I
observed NGC 2440 in my 18-inch in January 2000. I was a bit surprised
by how bright it appeared. It is brighter than the 10th magnitude listed.
The planetary was obviously non stellar at 100x and appeared as a tiny
smudge. The best view came at 425x, where it appeared distinctly bipolar,
as seen in my sketch on the left. At the heart of the nebula is two bright
knots that nearly touch. The surrounding nebulosity stretches in the directions
perpendicular to a line between the knots, and is brighter and extends
farther to one side. This one's definitely going on my list favorites due
to its interesting structure.
This is the view of the field in a 6-inch at 50x.
Millennium Star Atlas Vol I Chart 319
Sky Atlas 2000 Chart 12
Uranometria 2000 Vol II Chart 319