I really like this picture, but it drove me crazy!
My first thought was, oh, NGC 3532, yes, that's the Wishing Well cluster
. A nice one. But hey, wait a minute - NGC 357
2? What's that? Why have I never heard of that one?
So I checked my software and got totally confused. The first thing I saw when I asked Guide to take me to NGC 3572 was a big, sparsely populated dashed circle described as Collinder 240. I googled Collinder 240 star cluster and got the Coathanger asterism
, Collinder 399. Thanks a million, Google.
My software also showed me dashed circles named Hogg 10 and Hogg 11 without any stars inside. Thanks, Guide. I searched for Hogg 10 and 11 on the net, Google gave me Ima Hogg
(the name for some reason made me think of Miss Piggy)
and, after a non-negligible amount of persuasion, Google eventually gave me this 1974 paper
Then I zoomed into Collinder 240 in my software and found NGC 3572, which looked like a total confusion. Instead of clearly marked clickable dots representing stars I got a blurry, messy gray black and white photo made up of a mixture of non-clickable bleeding pixel light sources and clickable dots overlapping other light sources. Five of the clickable dots were an angry red color, as if they represented stars as red as Betelgeuse. Well, I didn't see any deep red stars in either the APOD or in the ESO picture. Even though the dots were clickable, they contained no information apart from the stars' J-K magnitude.
So I tried to compare the position of the brightest stars I could see with the position of the stars in the ESO picture. Again it drove me crazy, until I realized that the ESO picture wasn't north up. I was still unable to make a mental "shift" of the picture to figure out the positions of the stars in the ESO picture compared with the north up position of NGC 3572 in my software. By the way, I'm not sure that today's APOD is north up, either.
To make the situation impossible, my software, which usually shows me nebulas as gray outlines, showed me no nebulosity whatsoever around NGC 3572.
So I returned to the 1974 paper about southern clusters and their reddening. And lo and behold! There, on page 148
, was a black and white picture of NGC 3572! I could, indeed, match the positions of the stars in the black and white picture in my software with the black and white picture of the NGC 3572 in the 1974 paper. Note the total absence of nebulosity in the 1974 picture.
Okay. I am convinced that my software really shows me NGC 3572. I'm less certain of today's APOD and the ESO picture!
One more thing. Today's APOD looks pretty darn brilliant. It looks better than the ESO picture. Bear in mind that NGC 3572 is not only close to the Carina Nebula (not all that close, though), but it is faint! Really! The brightest star in it, according to my software, is an eight magnitude star of spectral class B2.
So I will say that Josep M. Drudis has shown us a spectacular portrait of a cluster and its nebulosity that has so far flown completely under the radar
in the world of Google.
NGC 3572 (top, in the top left picture) with Hogg 10 and 11.
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