Object of the Week Mar 11, 2012 - The Boomerang Nebula
ESO 172-7 aka the Boomerang Nebula
J2000 R.A. 12h 44m 46.1s Dec -54°31'10"
Size (from NED): 1.45’ x .73’
Magnitude (from NED): 12.4V
A bipolar protoplanetary nebula in Centaurus, discovered in 1977-78 in the ESO Quick Blue survey. One interesting tidbit about the Boomerang is that it is currently the coldest known region in the universe, with a temperature of only one degree Kelvin. No emission lines are apparent, but there is sufficient dust reflecting light from the central star to allow the nebula to be seen.
I observed the Boomerang with a 20" f/4 dob in 2006 at the Texas Star Party. From my log notes:
The southern-most object I've observed from my usual latitude, 30 degrees north.
My 25" wouldn't point low enough without dismantling the altitude drive, so I enlisted Barbara Wilson's 20". The Boomerang shared the field of view with a tree, which stuck down from the top of the fov. The viewing position consisted of lying stretched out on the ground, head propped up on one arm to reach the eyepiece.
At 120x, seen with averted vision only.
At 182x, seen intermittently with direct vision, held easily with averted vision.
At 290x, dim but held steadily with direct vision.
The nebula was elongated in appearance, but no detail was visible due to the atmospheric effects of viewing with the telescope pointed almost horizontally; it could easily have been mistaken for a galaxy.
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