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Old 17-07-2018, 04:25 PM
Placidus (Mike and Trish)
Narrowing the band

Placidus is offline
 
Join Date: Mar 2011
Location: Euchareena, NSW
Posts: 3,719
NGC 6872 in Pavo - the largest spiral in the sky, and 100 friends

The big daddy elliptical in the centre is NGC 6876, centre of a cluster of galaxies in south-eastern Pavo.

We were drawn to this rich cluster of galaxies because of the tidal stretching of the edge-on spiral NGC 6872, which is in the top left corner of the thumbnail.

Notice the intense star formation in the very blue spiral arms. The arm heading downward gets fainter and broader, and then hooks around to the right in a very faint blue club-like end. In our image, this club can be seen to be resolved into several small star-forming regions.

The salmon-pink centre shows a distinct bar, with what looks like a very tiny active nucleus.

Wikipedia says that it is interacting with IC4970, a small lenticular. We can indeed see what looks like a bridge of bright blue stars between the two.

Wiki says that tip to tip, 6872 is half a million light years across, or five times the size of the Milky Way. NASA says this colossus is the largest spiral in the sky. Some folk liken it to the shape of a condor, but condors are not radially symmetrical, so we think of it as more like a badly bent paper-clip.

The thumb is a crop on the most interesting part of the busy cluster of galaxies.

Full frame here.

In the full frame, there are at least another 170 clearly visible more or less distant galaxies.

Aspen CG16M on 20 inch PlaneWave. Luminance 17 hrs, RGB 3 hrs each, all in 30 min subs.

North is on the left. Frame is approximately 30 min arc across, 0.55 sec arc/pixel.

Hope you like it too.
Attached Thumbnails
Click for full-size image (NGC 6872 SE Pavo Lum 17hrs RGB 3hrs each Thumb.jpg)
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Last edited by Placidus; 17-07-2018 at 05:12 PM.
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