The bright dot just above the center of NGC 3184 is a type II supernova observed in 1999. (This is not the bright dot near the top of the galaxy, which is a nearby star, in our own galaxy.) NGC 3184 is about 50,000 light years across, or about half the size of our galaxy, and 40 million light years distant. NGC 3180 and 3181 are ionized hydrogen clouds in NGC 3184. NGC 3181 is the bright region down and to the right of the nucleus, on the inner spiral arm. NGC 3180 is the two bright regions further out on that arm, to the right of the bright foreground star noted above.

Below, an image of NGC 1384 taken years after the supernova of 1999 (and as it happens, rotated a few degrees counterclockwise, relative to the previous image). The location where the supernova occurred is now a faint, slightly blue and pinkish region, indicative of glowing hydrogen gas heated by hot, bright upper Main Sequence stars. The supernova was undoubtedly one of a number of massive stars in that region. Such stars have short lives, and over a period of a few million years, a number of siblings of the now extinct star will suffer similar fates. (Image Credits: Dan Smith/Adam Block/AURA/NSF/NOAO)

Per Dreyer, NGC 3199 (= John Herschel's GC 2067, 1860 RA 10 11 46, NPD 147 15.7) is "a remarkable object, very bright, very large, falcate, double star involved" (falcate means curved, like a sickle). The second IC adds "No nebula on photos at Arequipa (Harv. Ann. xxvi. 207). h. observed it 4 times. Has it disappeared?" The position precesses to RA 10 16 44.9, Dec -57 57 35, which is centered on the brightest part of the sickle-shaped arc which is all that Dunlop or Herschel could have observed, so the identification is certain. However, NGC 3199 is now often thought of as the more or less round (but mostly far fainter) nebula to the east of the sickle; hence the difference between Herschel's position and the one listed above, which is close to the center of the circular region (and is used as the center of the wide-field image below). As for the fact that Dunlop's observation was ignored (based on Corwin's notes): Dunlop obtained a South Polar Distance a degree too large, putting his #322 a degree north of its correct position; and as a result, Herschel wasn't able to find Dunlop's object. When he did find the nebula he used a North Polar Distance for his calculations, reducing the chance of noticing the similarity to Dunlop's position, so his independent discovery appeared to be the only observation of the nebula at the time Dreyer compiled the NGC (and as noted in the second IC, there were some puzzlingly futile efforts to find it again). The equivalence between Dunlop and Herschel's observations is a relatively recent discovery, and therefore not generally noted even now.
     (Physical Data: About 20 by 15 arcmin apparent size, 12000 light years away, and therefore about 75 light years across. The odd shape appears to be due to an uneven distribution of clouds of gas surrounding the Wolf-Rayet star near the center of the nebula. More to follow in the next iteration of this page)