ASTRO: NGC 6691

NGC 6691 is a spiral galaxy located in Draco some 260 million
light-years from us. Arp has a category in his atlas for 3 armed
spirals. All three he included are really two armed spirals with a
major spur off one to make the third arm. Thus I include this one as
falling into the same category. It has two main arms coming off the bar
and a large spur overlaying one of those arms that first goes north on
the western side of the galaxy they a second spur comes off it going
northeast. Much smaller spurs are seeing coming off the other arm. The
galaxy to the south is listed in a note at NED as being a companion.
This field is so poorly studied it has no catalog entry in NED. All
other galaxies in the image that NED identifies are from the 2MASS IR
catalog which only picks up galaxies bright in 2 micron IR radiation.
The companion apparently doesn't have enough.

In the cropped and enlarged image I've put NGC 6691 well off center to
catch, in the opposite corner, two or maybe three galaxies. The two
brightest are in the 2MASS catalog as 2MASX J18400484+5545142 and 2MASX
J18400579+5545152. I can't tell for sure if the former is separate from
the disk galaxy behind it or just a very bright core. I tend to think
it is just another elliptical/S0 like the other one to the east and the
disk object is a third galaxy whose core is mostly hidden by the 2MASS
galaxy. NED is of no help here listing no size for either of the two
galaxies.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick
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Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Correction:
14" LX200R @ f/10, L=6x10' RGB=2x10', STL-11000XM, Paramount ME

I used 6 luminance subs not 4.
Rick

On 11/9/2011 2:37 PM, Rick Johnson wrote:


14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick


--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".