Object of the Week August 18, 2013 - NGC 247 & Burbidge's Chain

[Paul Alsing]

Object of the Week August 18, 2013
NGC 247 & Burbidge's Chain
Cetus


Position - NGC 247
RA 00 47 08.6
DEC -20 45 38

Mag = 9.7(B); Size 20.0'x5.0'; SB = 14.4 (All magnitudes taken from SkyTools)

Type: Dwarf Spiral Galaxy
NGC 247 is a member of the Sculptor Group, along with NGC 55, NGC 300, NGC 253, and NGC 7793, along with 10 or 12 others. This is the closest galaxy group to our Local Group at about 11 or 12 million LY's away.

In my 25" it is easy enough to see, but its 9.7 magnitude is misleading because it is large, and therefore has a low surface brightness. There is a 9.5 magnitude foreground star at the brighter, skinnier southern end, and the slightly wider northern end is dimmer, and it is not easy to detect the actual edge of the galaxy, it just gradually fades away. I only just read that this guy is sometimes called The Needle's Eye galaxy because of a large dark area centered near the northern end, and sure enough, in deep photos there indeed seems to be a dark patch, making the whole thing reminiscent of a rather plump needle. I don't know if this feature is visible or not, I never knew to look for it and it certainly didn't jump out at me... let us know if you've seen it!

I observed NGC 247 in the first place because it is the jumping-off point for locating the tiny string of faint galaxies otherwise known as Burbidge's Chain, located a scant 16 arcminutes north-northeast of the center of NGC 247. The (4) components of Burbidge's Chain are:

a = MCG-4-3-10, mag 14.6(B)

b = MCG-4-3-13, mag 14.8(B)

c = MCG-4-3-11, mag 16.0(B)

d = MCG-4-3-12, mag 17.5(B)

NGC-247 inv.jpgCETUS - burbidge.jpg



I've observed this little string of tiny galaxies several times over the years, most recently at CalStar a few of years ago, and in 25" there is no trouble seeing 3 of the 4 galaxies, with the "d" component being a certified stinker. I was observing with Greg LaFlamme, an experienced observer with much younger eyes, and Greg said it was just an occasional flicker in the eyepiece for a small percentage of the time. After trying for many minutes, I thought that perhaps I saw it, too... but someone once told me I was gullible, and I believed him... so maybe I did, maybe I didn't. The night was good but not great. I think I'll try it at CalStar again, in October.

“Give it a go and let us know!”