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View Full Version : Object of the Week, May 11 2014: NGC 6240, the Rumpled Starfish



reiner
May 10th, 2014, 01:03 PM
NGC 6240

Ophiuchus
16 52 58
+02 24 01

2.2'X0.9', mag 13.4

This is an actually small galaxy in Ophiuchus. I stumbled over it when reading an online article by Greg Crinklaw, who also nicknamed it "Rumpled Starfish" due to its peculiar distorted shape

http://observing.skyhound.com/archives/jun/NGC_6240.html

http://www.reinervogel.net/exotic/images/NGC6240.jpg

SDSS image with North up


http://www.reinervogel.net/exotic/images/NGC6240HST.jpg

HST image with North to the left

NGC 6240 is the result of a collision between two galaxies, that finally merged into a single galaxy (http://apod.nasa.gov/apod/ap090618.html). In the infrared spectral range, this galaxy is one of the brightest objects in the sky. As a remainder of this merging process, the galaxy harbors two super massive Black Holes in its center, which are the central Black Holes of its progenitors.

I observed this galaxy the first time in 2009 at my regular observing site at 1200 m in southern Germany. Accidentally, I met Frank Richardsen up on the mountain, who also joined to have a look at this galaxy.

With my 22", this galaxy is not difficult at all, but is is not a really easy object when it comes to seeing the details. It has a brightness of mag 12.8 and a size of about 2'. The galaxy is next to a mag 13 star and appears to wind around this star to some extent. That's what I could see at first glance.

Spending some time on this object, more details became discernible and at least three of the spiral arms could be made out after careful observation. Two of them are oriented towards N and S, respectively (bent around the star), while another arm is on the W side protruding towards SW.

Although these details are plainly visible in the image, they are not easy to see at the eyepiece and require high power and patience.

“GIVE IT A GO AND LET US KNOW”
GOOD LUCK AND GREAT VIEWING!

Uwe Glahn
May 11th, 2014, 09:08 AM
Hi Reiner,

yes, I also remember only subtle, faint and small details within the galaxy. Even with 27" under very dark skies not very easy but interesting enough for another try.

27", 586x, NELM 7m+, Seeing II
http://www.deepsky-visuell.de/Zeichnungen/NGC6240.jpg